Publications by authors named "Zanariah Hashim"

5 Publications

  • Page 1 of 1

Entrapment of porous cross-linked enzyme aggregates of maltogenic amylase from Bacillus lehensis G1 into calcium alginate for maltooligosaccharides synthesis.

Int J Biol Macromol 2020 May 5;150:80-89. Epub 2020 Feb 5.

School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia; Institute of Bioproduct Development, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia. Electronic address:

Maltooligosaccharides (MOSs) are emerging oligosaccharides in food-based applications and can be synthesized through the enzymatic synthesis of maltogenic amylase from Bacillus lehensis G1 (Mag1). However, the lack of enzyme stability makes this approach unrealistic for industrial applications. The formation of cross-linked enzyme aggregates (CLEAs) is a promising tool for improving enzyme stability, and the substrate accessibility problem of CLEA formation was overcome by the addition of porous agents to generate porous CLEAs (p-CLEAs). However, p-CLEAs exhibited high enzyme leaching and low solvent tolerance. To address these problems, p-CLEAs of Mag1 (Mag1-p-CLEAs) were entrapped in calcium alginate beads (CA). Mag1-p-CLEAs-CA prepared with 2.5% (w/v) sodium alginate and 0.6% (w/v) calcium chloride yielded 53.16% (17.0 U/mg) activity and showed a lower deactivation rate and longer half-life than those of entrapped free Mag1 (Mag1-CA) and entrapped non-porous Mag1-CLEAs (Mag1-CLEAs-CA). Moreover, Mag1-p-CLEAs-CA exhibited low enzyme leaching and high tolerance in various solvents compared to Mag1-p-CLEAs. A kinetic study revealed that Mag1-p-CLEAs-CA exhibited relatively high affinity towards beta-cyclodextrin (β-CD) (K = 0.62 mM). MOSs (300 mg/g) were synthesized by Mag1-p-CLEAs-CA at 50 °C. Finally, the reusability of Mag1-p-CLEAs-CA makes them as a potential biocatalyst for the continuous synthesis of MOSs.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.02.032DOI Listing
May 2020

A porous-cross linked enzyme aggregates of maltogenic amylase from Bacillus lehensis G1: Robust biocatalyst with improved stability and substrate diffusion.

Int J Biol Macromol 2020 Apr 20;148:1222-1231. Epub 2019 Nov 20.

School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Skudai, Johor 81310, Malaysia; Institute of Bioproduct Development, Universiti Teknologi Malaysia, Skudai, Johor 81310, Malaysia. Electronic address:

Enzymatic synthesis of maltooligosaccharides is hampered due to lack of stability of soluble enzyme. This limitation can be tackled by cross linked enzyme aggregates (CLEAs) immobilization approach. However, substrate diffusion is a major bottleneck in cross linking technology. Herein, CLEAs of maltogenic amylase from Bacillus lehensis G1 (Mag1) was developed with addition of porous agent (Mag1-p-CLEAs). Comparison of thermal, pH and kinetic analysis with CLEAs without porous agent (Mag1-CLEAs) and free Mag1 was performed. Mag1-p-CLEAs with porous structure prepared at 0.8% (w/v) of citrus pectin (porous agent), 0.25% (w/v) of chitosan (cross linker) and cross linked for 1.5 h yielded 91.20% activity. 80% of activity is retained after 30 min of incubation at 40 °C and showed longer half-life than free Mag1 and Mag1-CLEAs. Mag1-p-CLEAs also showed pH stability at acidic and alkaline pH. The 1.68-fold increase in V value in comparison to Mag1-CLEAs showed that the presence of pores of Mag1-p-CLEAs enhanced the beta-cyclodextrin accessibility. The increase in high catalytic efficiency (K/K) value, 1.90-fold and 1.05-fold showed that it also has better catalytic efficiency than free Mag1 and Mag1-CLEAs, respectively. Mag1-p-CLEAs not only improved substrate diffusibility of CLEAs, but also leads to higher thermal and pH stability of Mag1.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.10.101DOI Listing
April 2020

Comparative study of herbal plants on the phenolic and flavonoid content, antioxidant activities and toxicity on cells and zebrafish embryo.

J Tradit Complement Med 2017 Oct 16;7(4):452-465. Epub 2017 Jan 16.

Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030, Malaysia.

Natural antioxidants derived from plants have shown a tremendous inhibitory effect on free radicals in actively metabolizing cells. Overproduction of free radicals increases the risk factor of chronic diseases associated with diabetes, cancer, arthritis and cardiovascular disease. and are ethnomedicinal plants used in the Asian region to treat various illnesses from a common fever to metabolic disease. In this study, we have quantified the total phenolic (TPC) and flavonoid content (TFC) in these plants and its inhibitory effect on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals as well as the cytotoxicity effect on cell lines proliferation and zebrafish embryogenesis. Results showed that and have the highest phenolic and flavonoid content. Furthermore, both herbs significantly inhibited the formation of DPPH and ABTS free radicals. Meanwhile, exhibited minimum cytotoxicity and embryotoxicity on tested models. Good correlation between IC50 of 3T3-L1 cells and LC50 embyrotoxicity was also found. This study revealed the potent activity of antioxidant against free radical and the toxicology levels of the tested herbal plants.
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http://dx.doi.org/10.1016/j.jtcme.2016.12.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5634737PMC
October 2017

Metabolic profiling of retrograde pathway transcription factors rtg1 and rtg3 knockout yeast.

Metabolites 2014 Jul 8;4(3):580-98. Epub 2014 Jul 8.

Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

Rtg1 and Rtg3 are two basic helix-loop-helix (bHLH) transcription factors found in yeast Saccharomyces cerevisiae that are involved in the regulation of the mitochondrial retrograde (RTG) pathway. Under RTG response, anaplerotic synthesis of citrate is activated, consequently maintaining the supply of important precursors necessary for amino acid and nucleotide synthesis. Although the roles of Rtg1 and Rtg3 in TCA and glyoxylate cycles have been extensively reported, the investigation of other metabolic pathways has been lacking. Characteristic dimer formation in bHLH proteins, which allows for combinatorial gene expression, and the link between RTG and other regulatory pathways suggest more complex metabolic signaling involved in Rtg1/Rtg3 regulation. In this study, using a metabolomics approach, we examined metabolic alteration following RTG1 and RTG3 deletion. We found that apart from TCA and glyoxylate cycles, which have been previously reported, polyamine biosynthesis and other amino acid metabolism were significantly altered in RTG-deficient strains. We revealed that metabolic alterations occurred at various metabolic sites and that these changes relate to different growth phases, but the difference can be detected even at the mid-exponential phase, when mitochondrial function is repressed. Moreover, the effect of metabolic rearrangements can be seen through the chronological lifespan (CLS) measurement, where we confirmed the role of the RTG pathway in extending the yeast lifespan. Through a comprehensive metabolic profiling, we were able to explore metabolic phenotypes previously unidentified by other means and illustrate the possible correlations of Rtg1 and Rtg3 in different pathways.
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http://dx.doi.org/10.3390/metabo4030580DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4192681PMC
July 2014

Construction of a metabolome library for transcription factor-related single gene mutants of Saccharomyces cerevisiae.

J Chromatogr B Analyt Technol Biomed Life Sci 2014 Sep 27;966:83-92. Epub 2014 May 27.

Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address:

Transcription factors (TFs) play an important role in gene regulation, providing control for cells to adapt to ever changing environments and different physiological states. Although great effort has been taken to study TFs through DNA-protein binding and microarray gene expression experiments, the understanding of transcriptional regulation is still lacking, due to lack of information that links TF regulatory events and final phenotypic change. Here, we focused on metabolites as the final readouts of gene transcription process. We performed metabolite profiling of 154 Saccharomyces cerevisiae's single gene knockouts each defective in a gene encoding transcription factor and built a metabolome library consists of 84 metabolites with good reproducibility. Using the metabolome dataset, we obtained significant correlations and identified differential strains that exhibit altered metabolism compared to control. This work presents a novel metabolome dataset library which will be invaluable for researchers working on transcriptional regulation and yeast biology in general.
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http://dx.doi.org/10.1016/j.jchromb.2014.05.041DOI Listing
September 2014