Publications by authors named "Pau-Loke Show"

193 Publications

Anaerobic digestate as a low-cost nutrient source for sustainable microalgae cultivation: A way forward through waste valorization approach.

Sci Total Environ 2021 Sep 3;803:150070. Epub 2021 Sep 3.

School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang, Malaysia.

To suffice the escalating global energy demand, microalgae are deemed as high potential surrogate feedstocks for liquid fuels. The major encumbrance for the commercialization of microalgae cultivation is due to the high costs of nutrients such as carbon, phosphorous, and nitrogen. Meanwhile, the organic-rich anaerobic digestate which is difficult to be purified by conventional techniques is appropriate to be used as a low-cost nutrient source for the economic viability and sustainability of microalgae production. This option is also beneficial in terms of reutilize the organic fraction of solid waste instead of discarded as zero-value waste. Anaerobic digestate is the side product of biogas production during anaerobic digestion process, where optimum nutrients are needed to satisfy the physiological needs to grow microalgae. Besides, the turbidity, competing biological contaminants, ammonia and metal toxicity of the digestate are also potentially contributing to the inhibition of microalgae growth. Thus, this review is aimed to explicate the feasibility of utilizing the anaerobic digestate to cultivate microalgae by evaluating their potential challenges and solutions. The proposed potential solutions (digestate dilution and pre-treatment, microalgae strain selection, extra organics addition, nitrification and desulfurization) corresponding to the state-of-the-art challenges are applicable as future directions of the research.
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http://dx.doi.org/10.1016/j.scitotenv.2021.150070DOI Listing
September 2021

Cultivation of Chlorella vulgaris on dairy waste using vision imaging for biomass growth monitoring.

Bioresour Technol 2021 Sep 8;341:125892. Epub 2021 Sep 8.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Continuous automation of conventional industrial operations with smart technology have drawn significant attention. Firstly, the study investigates on optimizing the proportion of industrial biscuit processing waste powder, (B) substituted into BG-11 as a source of cultivation medium for the growth of C. vulgaris. Various percentages of industrial biscuit processing waste powder, (B) were substituted in the inorganic medium to analyse the algal growth and biochemical composition. The use of 40B combination was found to yield highest biomass concentration (4.11 g/L), lipid (260.44 mg/g), protein (263.93 mg/g), and carbohydrate (418.99 mg/g) content compared with all the other culture ratio combination. Secondly, the exploitation of colour acquisition was performed onto C. vulgaris growth phases, and a novel photo-to-biomass concentration estimation was conducted via image processing for three different colour model pixels. Based on linear regression analysis the red, green, blue (RGB) colour model can interpret its colour variance precisely.
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http://dx.doi.org/10.1016/j.biortech.2021.125892DOI Listing
September 2021

Challenges and recent trends with the development of hydrogel fiber for biomedical applications.

Chemosphere 2021 Aug 23;287(Pt 1):131956. Epub 2021 Aug 23.

Department of Chemical and Environmental Engineering, Faculty Science and Engineering, University of Nottingham, Malaysia, 43500, Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Hydrogel is the most emblematic soft material which possesses significantly tunable and programmable characteristics. Polymer hydrogels possess significant advantages including, biocompatible, simple, reliable and low cost. Therefore, research on the development of hydrogel for biomedical applications has been grown intensely. However, hydrogel development is challenging and required significant effort before the application at an industrial scale. Therefore, the current work focused on evaluating recent trends and issues with hydrogel development for biomedical applications. In addition, the hydrogel's development methodology, physicochemical properties, and biomedical applications are evaluated and benchmarked against the reported literature. Later, biomedical applications of the nano-cellulose-based hydrogel are considered and critically discussed. Based on a detailed review, it has been found that the surface energy, intermolecular interactions, and interactions of hydrogel adhesion forces are major challenges that contribute to the development of hydrogel. In addition, compared to other hydrogels, nanocellulose hydrogels demonstrated higher potential for drug delivery, 3D cell culture, diagnostics, tissue engineering, tissue therapies and gene therapies. Overall, nanocellulose hydrogel has the potential for commercialization for different biomedical applications.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131956DOI Listing
August 2021

Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater.

J Hazard Mater 2021 08 23;416:125912. Epub 2021 Apr 23.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.
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http://dx.doi.org/10.1016/j.jhazmat.2021.125912DOI Listing
August 2021

How does the Internet of Things (IoT) help in microalgae biorefinery?

Biotechnol Adv 2021 Aug 25:107819. Epub 2021 Aug 25.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Microalgae biorefinery is a platform for the conversion of microalgal biomass into a variety of value-added products, such as biofuels, bio-based chemicals, biomaterials, and bioactive substances. Commercialization and industrialization of microalgae biorefinery heavily rely on the capability and efficiency of large-scale cultivation of microalgae. Thus, there is an urgent need for novel technologies that can be used to monitor, automatically control, and precisely predict microalgae production. In light of this, innovative applications of the Internet of things (IoT) technologies in microalgae biorefinery have attracted tremendous research efforts. IoT has potential applications in a microalgae biorefinery for the automatic control of microalgae cultivation, monitoring and manipulation of microalgal cultivation parameters, optimization of microalgae productivity, identification of toxic algae species, screening of target microalgae species, classification of microalgae species, and viability detection of microalgal cells. In this critical review, cutting-edge IoT technologies that could be adopted to microalgae biorefinery in the upstream and downstream processing are described comprehensively. The current advances of the integration of IoT with microalgae biorefinery are presented. What this review discussed includes automation, sensors, lab-on-chip, and machine learning, which are the main constituent elements and advanced technologies of IoT. Specifically, future research directions are discussed with special emphasis on the development of sensors, the application of microfluidic technology, robotized microalgae, high-throughput platforms, deep learning, and other innovative techniques. This review could contribute greatly to the novelty and relevance in the field of IoT-based microalgae biorefinery to develop smarter, safer, cleaner, greener, and economically efficient techniques for exhaustive energy recovery during the biorefinery process.
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http://dx.doi.org/10.1016/j.biotechadv.2021.107819DOI Listing
August 2021

Microalgal-based biochar in wastewater remediation: Its synthesis, characterization and applications.

Environ Res 2021 Aug 25;204(Pt A):111966. Epub 2021 Aug 25.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Microalgae are drawing attentions among researchers for their biorefinery use or value-added products. The high production rate of biomasses produced are attractive for conversion into volatile biochar. Torrefaction, pyrolysis and hydrothermal carbonization are the recommended thermochemical conversion techniques that could produce microalgal-based biochar with desirable physiochemical properties such as high surface area and pore volume, abundant surface functional groups, as well as functionality such as high adsorption capacity. The characterizations of the biochar significantly influence the mechanisms in adsorption of pollutants from wastewaters. Specific adsorption of the organic and inorganic pollutants from the effluent are reviewed to examine the adsorption capacity and efficiency of biochar derived from different microalgae species. Last but not least, future remarks over the challenges and improvements are discussed accordingly. Overall, this review would discuss the synthesis, characterization and application of the microalgal-based biochar in wastewater.
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http://dx.doi.org/10.1016/j.envres.2021.111966DOI Listing
August 2021

Algae as potential feedstock for various bioenergy production.

Chemosphere 2021 Aug 19;287(Pt 1):131944. Epub 2021 Aug 19.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Depletion of non-renewable feedstock and severe wastewater pollution due to human activities have created negative impact to living organisms. The potential solution is to implement wastewater treatment and bioelectricity production through algae-based microbial fuel cell. The algae biomass produced from microbial fuel cell could be further processed to generate biofuels through their unique compositions. The consumption of nutrients in wastewater through algae cultivation and biomass produced to be utilized for energy supply have showed the potential of algae to solve the issues faced nowadays. This review introduces the background of algae and mitigation of wastewater using algae as well as the bioenergy status in Malaysia. The mechanisms of nutrient assimilation such as nitrogen, phosphorus, carbon, and heavy metals are included, followed by the application of algae in microbial fuel cell's chambers. Lastly, the status of algae for bioenergy production are covered.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131944DOI Listing
August 2021

Treatment of Hospital wastewater with submerged aerobic fixed film reactor coupled with tube-settler.

Chemosphere 2021 Aug 10;286(Pt 3):131838. Epub 2021 Aug 10.

Department of Chemical and Environmental Engineering, Faculty Science and Engineering, University of Nottingham, 43500, Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

In this study, Hospital wastewater was treated using a submerged aerobic fixed film (SAFF) reactor coupled with tubesettler in series. SAFF consisted of a column with an up-flow biofilter. The biological oxygen demand (BOD), chemical oxygen demand (COD), nitrate and phosphate were the chosen pollutants for evaluation. The pollutants removal efficiency was determined at varying organic loading rates and hydraulic retention time. The organic loading rate was varied between 0.25 and 1.25 kg COD m d. The removal efficiency of SAFF and tubesettler combined was 75 % COD, 67 % BOD and 67 % phosphate, respectively. However, nitrate saw an increase in concentration by 25 %. SAFF contribution in the removal of COD, BOD and Phosphate was 48 %, 46 % and 29 %, respectively. While for accumulation of nitrate, it was responsible for 56%, respectively. Tubesettler performed better than SAFF with 52 %, 54 % and 69 % reduction of COD, BOD and phosphate, respectively. But in terms of nitrate, tubesettler was responsible for 44 % accumulation. The nutrient reduction decreased with an increase in the organic loading rate. Nitrification was observed in the SAFF and tubesettler, which indicated a well-aerated system. An anaerobic unit is required for completing the denitrification process and removing nitrogen from the effluent. The better performance of tubesettler over SAFF calls for necessitates extended retention time over design criteria. Further studies are beneficial to investigate the impact of pharmaceutical compounds on the efficiency of SAFF.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131838DOI Listing
August 2021

Multi-objective optimization of thermophysical properties of multiwalled carbon nanotubes based nanofluids.

Chemosphere 2021 Jul 27;286(Pt 2):131690. Epub 2021 Jul 27.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Selangor Darul Ehsan, Malaysia. Electronic address:

The experimental determination of thermophysical properties of nanofluid (NF) is time-consuming and costly, leading to the use of soft computing methods such as response surface methodology (RSM) and artificial neural network (ANN) to estimate these properties. The present study involves modelling and optimization of thermal conductivity and viscosity of NF, which comprises multi-walled carbon nanotubes (MWCNTs) and thermal oil. The modelling is performed to predict the thermal conductivity and viscosity of NF by using Response Surface Methodology (RSM) and Artificial Neural Network (ANN). Both models were tested and validated, which showed promising results. In addition, a detailed optimization study was conducted to investigate the optimum thermal conductivity and viscosity by varying temperature and NF weight per cent. Four case studies were explored using different objective functions based on NF application in various industries. The first case study aimed to maximize thermal conductivity (0.15985 W/m C) while minimizing viscosity (0.03501 Pa s) obtained at 57.86 °C and 0.85 NF wt%. The goal of the second case study was to minimize thermal conductivity (0.13949 W/m °C) and viscosity (0.02526 Pa s) obtained at 55.88 °C and 0.15 NF wt%. The third case study targeted maximizing thermal conductivity (0.15797 W/m °C) and viscosity (0.07611 Pa s), and the optimum temperature and NF wt% were 30.64 °C and 0.0.85,' respectively. The last case study explored the minimum thermal conductivity (0.13735) and maximum viscosity (0.05263 Pa s) obtained at 30.64 °C and 0.15 NF wt%.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131690DOI Listing
July 2021

Development of proton-exchange membrane fuel cell with ionic liquid technology.

Sci Total Environ 2021 Nov 24;793:148705. Epub 2021 Jun 24.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Broga Road, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Fuel cells (FCs) are a chemical fuel device which can directly convert chemical energy into electrical energy, also known as electrochemical generator. Proton exchange membrane fuel cells (PEMFCs) are one of the most appealing FC systems that have been broadly developed in recent years. Due to the poor conductivity of electrolyte membrane used in traditional PEMFC, its operation at higher temperature is greatly limited. The incorporation of ionic liquids (ILs) which is widely regarded as a greener alternative compared to traditional solvents in the proton exchange membrane electrolyte shows great potential in high temperature PEMFCs (HT-PEMFCs). This review provides insights in the latest progress of utilizing ILs as an electrochemical electrolyte in PEMFCs. Besides, electrolyte membranes that are constructed by ILs combined with polybenzimidazole (PBI) have many benefits such as better thermal stability, improved mechanical properties, and higher proton conductivity. The current review aims to investigate the newest development and existing issues of ILs research in electrolyte and material selection, system fabrication method, synthesis of ILs, and experimental techniques. The evaluation of life cycle analysis, commercialization, and greenness of ILs are also discussed. Hence, this review provides insights to material scientists and develops interest of wider community, promoting the use of ILs to meet energy challenges.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148705DOI Listing
November 2021

Oxidative torrefaction performance of microalga Nannochloropsis Oceanica towards an upgraded microalgal solid biofuel.

J Biotechnol 2021 Sep 21;338:81-90. Epub 2021 Jul 21.

School of Information, Systems and Modelling, Faculty of Engineering and Information Technology, University of Technology Sydney, NSW, 2007, Australia.

Microalgae are a promising feedstock for carbon-neutral biofuel production due to their superior cellular composition. Alternatively, oxidative torrefaction has been recognized as a potential thermochemical technique for microalgal solid biofuel upgrading. Herein, by using microalga N. oceanica as a feedstock, several characterizations are adopted for evaluating the potential of oxidative torrefaction towards microalgal solid biofuel production. The oxidatively torrefied microalgae can be upgraded as lignite. After in-depth analysis, significant change in the surface microstructure of oxidatively torrefied microalgae is largely changed (via wrinkle and fragmentation) The hydrophobicity, thermal decomposition, thermal stability, and aromatization of oxidatively torrefied microalgae can be largely enhanced as the oxidative torrefaction severity increase. With the increasing torrefaction temperature, the hydrophobicity of oxidative torrefied microalgae gradually improved. The decomposition of C-2/3/5, and -OCH, the CO bonds of CHCO-, and the aromatization occurs via oxidative torrefaction according to the NMR analysis. For XPS analysis, torrefaction operation significantly decreases the carbide carbon and enhances the graphitization. As a result, the thermal stability of oxidatively torrefied microalgae is improved. Conclusively, the information obtained in this study can provide insights into the evaluation of oxidative torrefaction performance and fuel properties of microalgal solid biofuel, which may help accelerate the advancement of oxidative torrefaction industrialization.
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http://dx.doi.org/10.1016/j.jbiotec.2021.07.009DOI Listing
September 2021

Recent Progress in Harvest and Recovery Techniques of Mammalian and Algae Cells for Industries.

Indian J Microbiol 2021 Sep 23;61(3):279-282. Epub 2021 Mar 23.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan Malaysia.

In our modern world, biotechnology products play important roles not only in our health and culture, but also various industries such as food, agriculture, sewage treatment, biofuels, nutraceuticals, and pharmaceuticals. Rapid technological advances in biotechnology over the last few decades have allowed industrial integration of mammalian cells (like the Chinese hamster ovary cells) and algae cells in pharmaceutical and biofuel industries to produce commercial products and valuable biomolecules. However, the cost of cell harvest and recovery can become expensive depending on the harvesting technique, degree of purification, and intended use of the end-products. This has led to numerous research in exploring and developing efficient harvesting techniques. Therefore, in this review, the popular harvesting techniques and their recent applications will be discussed.
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http://dx.doi.org/10.1007/s12088-021-00930-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263815PMC
September 2021

Microalgal-Bacterial Consortia as Future Prospect in Wastewater Bioremediation, Environmental Management and Bioenergy Production.

Indian J Microbiol 2021 Sep 22;61(3):262-269. Epub 2021 Feb 22.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan Malaysia.

In the recent years, microalgae have captured researchers' attention as the alternative feedstock for various bioenergy production such as biodiesel, biohydrogen, and bioethanol. Cultivating microalgae in wastewaters to simultaneously bioremediate the nutrient-rich wastewater and maintain a high biomass yield is a more economical and environmentally friendly approach. The incorporation of algal-bacterial interaction reveals the mutual relationship of microorganisms where algae are primary producers of organic compounds from CO, and heterotrophic bacteria are secondary consumers decomposing the organic compounds produced from algae. This review would provide an insight on the challenges and future development of algal-bacterial consortium and its contribution in promoting a sustainable route to greener industry. It is believed that microalgal-bacterial consortia will be implemented in the near-future for sub-sequential treatment of wastewater bioremediation, bioenergy production and CO fixation, promoting sustainability and making extraordinary advancement in life sciences sectors.
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http://dx.doi.org/10.1007/s12088-021-00924-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263830PMC
September 2021

Self-healing epoxy coating synthesis by embedment of metal 2-methyl imidazole and acetylacetonate complexes with microcapsules.

Chemosphere 2021 Jul 8;285:131492. Epub 2021 Jul 8.

Department of Chemical and Environmental Engineering, Faculty Science and Engineering, University of Nottingham, Malaysia, 43500, Semenyih, Selangor, Darul Ehsan, Malaysia. Electronic address:

The restoration of mechanical properties is desired for creating the self-healing coatings with no corrosion capabilities. The encapsulation of epoxy resins is limited by various factors in urea and melamine formaldehyde microcapsules. An improved method was developed, where epoxy resin was encapsulated by individual wrapping of poly(melamine-formaldehyde) and poly(urea-formaldehyde) shell around emulsified epoxy droplets via oil-in-water emulsion polymerization method. The synthesized materials were characterized analytically. The curing of the epoxy was achieved by adding the [Ni/Co(2-MI)].2NO as a latent hardener and iron acetylacetonate [Fe(acac)] as a latent accelerator. Isothermal and non-isothermal differential scanning calorimetric analysis revealed lower curing temperature (T = 116 °C) and lower activation energies (Ea ≈ 69-75 kJ/mol). The addition of microcapsules and complexes did not adversely alter the flexural strength and flexural modulus of the epoxy coatings. The adhesion strength of neat coating decreased from 6310.8 ± 31 to 4720.9 ± 60 kPa and percent healing increased from 50.83 to 67.45% in the presence of acetylacetonate complex at 10 wt% of microcapsules.
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http://dx.doi.org/10.1016/j.chemosphere.2021.131492DOI Listing
July 2021

Perspective of Spirulina culture with wastewater into a sustainable circular bioeconomy.

Environ Pollut 2021 Sep 2;284:117492. Epub 2021 Jun 2.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Selangor Darul Ehsan, Malaysia. Electronic address:

Spirulina biomass accounts for 30% of the total algae biomass production globally. In conventional process of Spirulina biomass production, cultivation using chemical-based culture medium contributes 35% of the total production cost. Moreover, the environmental impact of cultivation stage is the highest among all the production stages which resulted from the extensive usage of chemicals and nutrients. Thus, various types of culture medium such as chemical-based, modified, and alternative culture medium with highlights on wastewater medium is reviewed on the recent advances of culture media for Spirulina cultivation. Further study is needed in modifying or exploring alternative culture media utilising waste, wastewater, or by-products from industrial processes to ensure the sustainability of environment and nutrients source for cultivation in the long term. Moreover, the current development of utilising wastewater medium only support the growth of Spirulina however it cannot eliminate the negative impacts of wastewater. In fact, the recent developments in coupling with wastewater treatment technology can eradicate the negative impacts of wastewater while supporting the growth of Spirulina. The application of Spirulina cultivation in wastewater able to resolve the global environmental pollution issues, produce value added product and even generate green electricity. This would benefit the society, business, and environment in achieving a sustainable circular bioeconomy.
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http://dx.doi.org/10.1016/j.envpol.2021.117492DOI Listing
September 2021

Removal of protein wastes by cylinder-shaped NaY zeolite adsorbents decorated with heavy metal wastes.

Int J Biol Macromol 2021 Aug 30;185:761-772. Epub 2021 Jun 30.

Department of Chemical Engineering, Graduate School of Biochemical Engineering, Ming Chi University of Technology, New Taipei City 243303, Taiwan. Electronic address:

Cylinder-shaped NaY zeolite was used as an adsorbent for eradicating both heavy metal ions (Cu, Zn, Ni, and Co) and proteins from the waste streams. As a pseudo-metal ion affinity adsorbent, NaY zeolite was used in the capture of heavy metal ions in the first stage. The amount (molar basis) of metal ions adsorbed onto NaY zeolite decreased in the order of Cu > Zn > Co > Ni. Bovine serum albumin (BSA) was utilized as a model of proteins used in the waste adsorption process by NaY zeolite. The adsorption capacities of NaY zeolite and Cu/NaY zeolite for BSA were 14.90 mg BSA/g zeolite and 84.61 mg BSA/g zeolite, respectively. Moreover, Cu/NaY zeolite was highly stable in the solutions made of 2 M NaCl, 500 mM imidazole or 125 mM EDTA solutions. These conditions indicated that the minimal probability of secondary contamination caused by metal ions and soluble proteins in the waste stream. This study demonstrates the potential of Cu/NaY zeolite complex as an efficient pseudo-metal chelate adsorbent that could remove metal ions and water-soluble proteins from wastewater concurrently.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.06.177DOI Listing
August 2021

Resource recovery from industrial effluents through the cultivation of microalgae: A review.

Bioresour Technol 2021 Oct 26;337:125461. Epub 2021 Jun 26.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Industrial effluents such as pharmaceutical residues, pesticides, dyes, and metal processes holds abundant value-added products (VAPs), where its recovery has become essential. The purpose of such recovery is for sustainable treatment, which is an approach that considers the economic, social, and environmental aspects. Microalgae with its potential in the recovery process from effluents, can reduce energy usage of waste management strategies and regenerate nutrients such as carbon, phosphorus, and nitrogen. Microalgae cultures offer the use of inorganic materials by microalgae for their growth and the help of bacteria to produce biomass, thus, resulting in the absence of secondary emissions due to its ability to eliminate volatile organic compounds. Moreover, recovered bioactive compounds are transformed into bioethanol, bio-fertilizers, biopolymer, health supplements and animal feed. Therefore, it is significant to focus on an economical and efficient utilization of microalgae in recovering nutrients that can be further used in various commercial applications.
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http://dx.doi.org/10.1016/j.biortech.2021.125461DOI Listing
October 2021

Discovery of α-Glucosidase Inhibitors from Marine Microorganisms: Optimization of Culture Conditions and Medium Composition.

Mol Biotechnol 2021 Jun 29. Epub 2021 Jun 29.

Institute of Biotechnology, Vietnam, Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, 100000, Hanoi, Vietnam.

Various studies showed that the suppression of α-glucosidase activity can impede the glucose absorption in our body, and therefore, it can be used to treat type 2 diabetes. Hence, the compounds with anti-α-glucosidase have gained considerable attention because of their potential application in diabetes treatment. In previous literature studies, these anti-α-glucosidase compounds were extracted from plants and fungus. Less studies are being conducted to identify the anti-α-glucosidase compounds in the microbial community. In this study, 23 marine bacterial strains were screened for their potential to suppress the α-glucosidase activity. The highest inhibitory activity was exhibited by isolated L06 which was identified as Oceanimonas smirnovii EBL6. The cultivation conditions, such as temperature and pH, were optimized to increase the production of α-glucosidase inhibitors by Oceanimonas smirnovii EBL6 strain. The result findings showed that the highest yield of α-glucosidase inhibitors can be obtained at the culture time of 120 h, fermentation temperature of 30 °C, and pH 4.6. Under these conditions, the inhibitory activity of α-glucosidase can reach 81%. The IC of n-butanol extract was 13.89 μg/ml, while standard acarbose was 31.16 μg/ml. Overall, these findings suggest that Oceanimonas smirnovii produces α-glucosidase inhibitors and could been applied in the biochemical and medicinal fields in the future.
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http://dx.doi.org/10.1007/s12033-021-00362-3DOI Listing
June 2021

Computational Lock and Key and Dynamic Trajectory Analysis of Natural Biophors Against COVID-19 Spike Protein to Identify Effective Lead Molecules.

Mol Biotechnol 2021 Oct 22;63(10):898-908. Epub 2021 Jun 22.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia.

New pandemic infection of coronaviridae family virus spread to more than 210 countries with total infection of 1,136,851 and 62,955 (4.6%) deaths until 5th April 2020. Which stopped the regular cycle of humankind but the nature is consistently running. There is no micro molecule remedy found yet to restore the regular life of people. Hence, we decided to work on natural biophores against the COVID proteins. As a first step, major phytoconstituents of antiviral herbs like Leucas aspera, Morinda citrifolia, Azadirachta indica, Curcuma longa, Piper nigrum, Ocimum tenuiflorum, and Corallium rubrum collected and performed the lock and key analysis with major spike protein of COVID-19 to find the best fitting lead biophore using computational drug design platform. The results of protocol run showed, phytoconstituents of Morinda citrifolia and Leucas aspera were found lower binding energy range of - 55.18 to - 25.34 kcal/mol, respectively and compared with Hydroxychloroquine (HCQ) (- 24.29 kcal/mol) and Remdesivir (- 25.38 kcal/mol). The results conclude that, core skeletons chromen, anthracene 9, 11 dione and long-chain alkyl acids/ester-containing biophores showen high stable antagonistic affinity with S-protein. Which leads the breakdown of spike protein and ACE2 receptor complex formation and host mechanism of corono virus. In addition, the dynamic trajectory analysis confirmed the complete denaturation of spike protein by the molecule 4-(24-hydroxy-1-oxo-5-n-propyltetracosanyl)-phenol from Leucas aspera and stability of spike-ligand complex. These biophores will aid the researcher to fabricate new promising analogue and being recommended to assess its COVID-19 treatment.
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http://dx.doi.org/10.1007/s12033-021-00358-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8219180PMC
October 2021

Effect of eggshell- and homo-type Ni/AlO catalysts on the pyrolysis of food waste under CO atmosphere.

J Environ Manage 2021 Sep 8;294:112959. Epub 2021 Jun 8.

School of Environmental Engineering, University of Seoul, Seoul, 02504, Republic of Korea. Electronic address:

This study highlights the potential of pyrolysis of food waste (FW) with Ni-based catalysts under CO atmosphere as an environmentally benign disposal technique. FW was pyrolyzed with homo-type Ni/AlO (Ni-HO) or eggshell-type Ni/AlO (Ni-EG) catalysts under flowing CO (50 mL/min) at temperatures from 500 to 700 °C for 1 h. A higher gas yield (42.05 wt%) and a lower condensable yield (36.28 wt%) were achieved for catalytic pyrolysis with Ni-EG than with Ni-HO (34.94 wt% and 40.06 wt%, respectively). In particular, the maximum volumetric content of H (21.48%) and CO (28.43%) and the lowest content of C-C (19.22%) were obtained using the Ni-EG. The formation of cyclic species (e.g., benzene derivatives) in bio-oil was also effectively suppressed (24.87%) when the Ni-EG catalyst and CO medium were concurrently utilized for the FW pyrolysis. Accordingly, the simultaneous use of the Ni-EG catalyst and CO contributed to altering the carbon distribution of the pyrolytic products from condensable species to value-added gaseous products by facilitating ring-opening reactions and free radical mechanisms. This study should suggest that CO-assisted catalytic pyrolysis over the Ni-EG catalyst would be an eco-friendly and sustainable strategy for disposal of FW which also provides a clean and high-quality source of energy.
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http://dx.doi.org/10.1016/j.jenvman.2021.112959DOI Listing
September 2021

Evaluating the application of antibiotic treatment using algae-algae/activated sludge system.

Chemosphere 2021 Nov 27;282:130966. Epub 2021 May 27.

School of Engineering, China Pharmaceutical University, Nanjing, 211198, China. Electronic address:

Biological methods are promising treatment methods to remove pollutants from wastewater. Recently, microalgae have been proved to be of strong application potential in wastewater treatment. In this study, a microalga - antibiotic treatment system was built to evaluate the treatment capacity of microalgae in antibiotic wastewater. In the group with Chlorella pyrenoidosa, the removal rate of cefradine was 41.47 ± 0.62% after 24 h of treatment, which was 3.4 times higher than that without microalgae (12.37 ± 2.30%). Algal decomposition was the main removal mechanism. Meanwhile, the effect of multiple microalgae species on antibiotic treatment was studied. The removal rates of cefradine by C. pyrenoidosa cultivated in the filtered fluid of Microcystis aeruginosa were 75.48 ± 0.29%, which was significantly higher than those by C. pyrenoidosa only. Those indicated that multiple microalgae species strategy was a potential enhancement strategy for algae-based antibiotic treatment. Finally, amoxicillin and norfloxacin were used to study the treatment potential of this technology for more different kinds antibiotics and the integration of microalgae with activated sludge was also investigated. Amoxicillin can be quickly removed by microalgae, but the removal effect of norfloxacin by microalgae is poor. The refractory antibiotic norfloxacin can be treated by co-culturing microalgae and activated sludge. Those showed the good expansibility of microalgae-based technology. The findings indicated that with microalgae-based antibiotic removal method has good application potential, and combined with other technologies, it can effectively remove the refractory antibiotics.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130966DOI Listing
November 2021

Benchtop Isolation and Characterisation of Small Extracellular Vesicles from Human Mesenchymal Stem Cells.

Mol Biotechnol 2021 Sep 1;63(9):780-791. Epub 2021 Jun 1.

School of Pharmacy, Faculty of Health & Medical Sciences, Taylor's University, No. 1, Jalan Taylor's, 47500, Subang Jaya, Malaysia.

The objective of this study is to develop a simple protocol to isolate and characterise small extracellular vesicles (sEVs) from human umbilical cord-derived MSCs (hUC-MSCs). hUC-MSCs were characterised through analysis of morphology, immunophenotyping and multidifferentiation ability. SEVs were successfully isolated by ultrafiltration from the conditioned medium of hUC-MSCs. The sEVs' size distribution, intensity within a specific surface marker population were measured with zetasizer or nanoparticle tracking analysis. The expression of surface and internal markers of sEVs was also assessed by western blotting. Morphology of hUC-MSCs displayed as spindle-shaped, fibroblast-like adherent cells. Phenotypic analysis by flow cytometry revealed that hUC-MSCs expressed MSC surface marker, including CD90, CD73, CD105, CD44 and exhibited the capacity for osteogenic, adipogenic and chondrogenic differentiation. Populations of sEVs with CD9, CD63 and CD81 positive were detected with size distribution in the diameter of 63.2 to 162.5 nm. Typical sEVs biomarkers such as CD9, CD63, CD81, HSP70 and TSG101 were also detected with western blotting. Our study showed that sEVs from hUC-MSCs conditioned medium were successfully isolated and characterised. Downstream application of hUC-MSCs-sEVs will be further explored.
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http://dx.doi.org/10.1007/s12033-021-00339-2DOI Listing
September 2021

Recent advances on food waste pretreatment technology via microalgae for source of polyhydroxyalkanoates.

J Environ Manage 2021 Sep 27;293:112782. Epub 2021 May 27.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible polyester which are biosynthesized from the intracellular cells of microalgae through the cultivation of organic food waste medium. Before cultivation process, food waste must undergo several pre-treatment techniques such as chemical, biological, physical or mechanical in order to solubilize complex food waste matter into simpler micro- and macronutrients in which allow bio-valorisation of microalgae and food waste compound during the cultivation process. This work reviews four microalgae genera namely Chlamydomonas, Chlorella, Spirulina, and Botryococcus, are selected as suitable species due to rapid growth rate, minimal nutrient requirement, greater adaptability and flexibility prior to lower the overall production cost and maximized the production of PHAs. This study also focuses on the different mode of cultivation for the accumulation of PHAs followed by cell wall destabilization, extraction, and purification. Nonetheless, this review provides future insights into enhancing the productivity of bioplastic derived from microalgae towards low-cost, large-scale, and higher productivity of PHAs.
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http://dx.doi.org/10.1016/j.jenvman.2021.112782DOI Listing
September 2021

Micro (nano) plastic pollution: The ecological influence on soil-plant system and human health.

Sci Total Environ 2021 Sep 17;788:147815. Epub 2021 May 17.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

Global plastic pollution has been a serious problem since many years and micro (nano) plastics (MNPs) have gained attention from researchers around the world. This is because MNPs able to exhibit toxicology and interact with potentially toxic elements (PTEs) in the environment, causing soil toxicity. The influences of MNPs on the soil systems and plant crops have been overlooked despite that MNPs can accumulate in the plant root system and generate detrimental impacts to the terrestrial environments. The consumption of these MNPs-contaminated plants or fruits by humans and animals will eventually lead to health deterioration. The identification and measurement of MNPs in various soil samples is challenging, making the understanding of the fate, environmental and ecological of MNPs in terrestrial ecosystem is limited. Prior to sample assessment, it is necessary to isolate the plastic particles from the environment samples, concentrate the plastic particles for analysis purpose to meet detection limit for analytical instrument. The isolation and pre-concentrated steps are challenging and may cause sample loss. Herein, this article reviews MNPs, including their fate in the environment and toxic effects exhibited towards soil microorganisms, plants and humans along with the interaction of MNPs with PTEs. In addition, various analysis methods of MNPs and management of MNPs as well as the crucial challenges and future research studies in combating MNPs in soil system are also discussed.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147815DOI Listing
September 2021

Advancement of green technologies: A comprehensive review on the potential application of microalgae biomass.

Chemosphere 2021 Oct 15;281:130886. Epub 2021 May 15.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500, Selangor Darul Ehsan, Malaysia. Electronic address:

Microalgae have drawn significant interest worldwide, owing to their enormous application potential in the green energy, biopharmaceutical, and nutraceutical industries. Many studies have proved and stated the potential of microalgae in the area of biofuel which is economically effective and environmentally friendly. Besides the commercial value, the potential of microalgae in environmental protection has also been investigated. Microalgae-based process is one of the most effective way to treat heavy metal pollution, compared to conventional methods, it does not release any toxic waste or harmful gases, and the aquatic organism will not receive any harmful effects. The potential dual role of microalge in phytoremedation and energy production has made it widely explored for its capability. The interest of microalgae in various application has motivated a new focus in green technologies. Considering the rapid population growth with the continuous increase on the global demand and the application of biomass in diverse field, significant upgrades have been performed to accommodate green technological advancement. In the past decade, noteworthy advancement has been made on the technology involving the diverse application of microalgae biomass. This review aims to explore on the application of microalgae and the development of green technology in various application for microalgae biomass. There is great prospects for researchers in this field to delve into other potential utilization of microalgae biomass not only for bioremediation process but also to generate revenues from microalgae by incorporating clean and green technology for long-term sustainability and environmental benefits.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130886DOI Listing
October 2021

A comprehensive review on the techniques for coconut oil extraction and its application.

Bioprocess Biosyst Eng 2021 Sep 19;44(9):1807-1818. Epub 2021 May 19.

Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia.

Virgin coconut oil is a useful substance in our daily life. It contains a high percentage of lauric acid which has many health benefits. The current industry has developed several methods to extract the oil out from the coconut fruit. This review paper aims to highlight several common extraction processes used in modern industries that includes cold extraction, hot extraction, low-pressure extraction, chilling, freezing and thawing method, fermentation, centrifugation, enzymatic extraction and supercritical fluid carbon dioxide. Different extraction methods will produce coconut oil with different yields and purities of lauric acid, thus having different uses and applications. Challenges that are faced by the industries in extracting the coconut oil using different methods of extraction are important to be explored so that advancement in the oil extraction technology can be done for efficient downstream processing. This study is vital as it provides insights that could enhance the production of coconut oil.
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http://dx.doi.org/10.1007/s00449-021-02577-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8132276PMC
September 2021

Development of an extended model for the permeation of environmentally hazardous CO gas across asymmetric hollow fiber composite membranes.

J Hazard Mater 2021 Sep 5;417:126000. Epub 2021 May 5.

Department of Chemical and Environmental Engineering, Faculty Science and Engineering, University of Nottingham, Malaysia, 43500 Semenyih, Selangor Darul Ehsan, Malaysia. Electronic address:

This study presents an extended thermodynamic and phenomenological combined model to mitigate the environmental hazardous acid gas over composite membranes. The model has been applied to an acid gas such as carbon dioxide (CO) for its permeation through polyetherimide incorporated montmorillonite (Mt) nanoparticles hollow fiber asymmetric composite membranes. The well-established non-equilibrium lattice fluid (NELF) model for penetrating low molecular weight penetrant in a glassy polyetherimide (PEI) was extended to incorporate the other important polymer/filler system features such as tortuosity in acid gas diffusion pathways resulted from layered filler aspect ratio and concentration. The model mentioned above predicts the behavior of acid gas in PEI-Mt composite membranes based on thermodynamic characteristics of CO and PEI and tortuosity due to Mt. The calculated results are compared to experimentally determined values of CO permeability through PEI-Mt composite asymmetric hollow fiber membranes at varying transmembrane pressures and Mt concentrations. A reasonable agreement was found between the model predicted behavior and experimentally determined data in terms of CO solubility, Mt concentration and aspect ratio were calculated based on average absolute relative error (%AARE). The proposed modified model efficiently predicts the CO permeance across MMMs up to 3 wt% Mt loadings and 6 bar pressure with ± 10%AARE.
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http://dx.doi.org/10.1016/j.jhazmat.2021.126000DOI Listing
September 2021

Isolation and characterization of a novel Lactobacillus plantarum MMB-07 from traditional Suanyu for Acanthogobius hasta fermentation.

J Biosci Bioeng 2021 Aug 7;132(2):161-166. Epub 2021 May 7.

Department of Chemical and Environmental Engineering, University of Nottingham Malaysia, Jalan Broga, Semenyih, 43500 Selangor, Malaysia. Electronic address:

As one of Lianyungang's most famous specialties, Acanthogobius hasta is delicious and nutritious fish, but is extremely susceptible to spoilage during transportation and storage. In this study, Lactobacillus plantarum MMB-07 was isolated from traditional fermented sour fish to reduce losses and improve the utilization and food value of A. hasta. L. plantarum MMB-07 had good ability of acid production and acid resistance. Moreover, it could also inhibit common pathogens in food or aquatic products to ensure the safety of fermented products. MMB-07 was used to ferment A. hasta and obtain fermented Suanyu rich in nutrition value and good flavor. The volatile base nitrogen was 18.44 mg/100 g and the fermented fish meat maintained second-grade freshness. Thiobarbituric acid assay was 0.90 mg/kg and fat in fish meat was oxidized to a low degree. The studies indicated that MMB-07 has a high application prospect in low salt fermented fish.
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http://dx.doi.org/10.1016/j.jbiosc.2020.12.016DOI Listing
August 2021

Stability evaluation and formula optimization of cellulose-based scaffold for the air-liquid interface cultivation of Navicula incerta.

Environ Res 2021 08 8;199:111298. Epub 2021 May 8.

School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300, Nibong Tebal, Pulau Pinang, Malaysia. Electronic address:

Culture scaffolds allow microalgae cultivation with minimum water requirement using the air-liquid interface approach. However, the stability of cellulose-based scaffolds in microalgae cultivation remains questionable. In this study, the stability of regenerated cellulose culture scaffolds was enhanced by adjusting TiO loading and casting gap. The membrane scaffolds were synthesized using cellulose dissolved in NaOH/urea aqueous solution with various loading of TiO nanoparticles. The TiO nanoparticles were embedded into the porous membrane scaffolds as proven by Fourier transform infrared spectra, scanning electron microscopic images, and energy-dispersive X-ray spectra. Although surface hydrophilicity and porosity were enhanced by increasing TiO and casting gap, the scaffold pore size was reduced. Cellulose membrane scaffold with 0.05 wt% of TiO concentration and thickness of 100 μm attained the highest percentage of Navicula incerta growth rate, up to 37.4%. The membrane scaffolds remained stable in terms of weight, porosity and pore size even they were immersed in acidic solution, hydrogen peroxide or autoclaved at 121 °C for 15 min. The optimal cellulose membrane scaffold is with TiO loading of 0.5 wt% and thickness of 100 μm, resulting in supporting the highest N. incerta growth rate and and exhibits good membrane stability.
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http://dx.doi.org/10.1016/j.envres.2021.111298DOI Listing
August 2021
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