Publications by authors named "Guangyang Jiang"

8 Publications

  • Page 1 of 1

Exoproduction and biochemical characterization of a novel serine protease from L9 with hide-dehairing activity.

J Microbiol Biotechnol 2021 Nov 20;32(1). Epub 2021 Nov 20.

Key Laboratory of Leather Chemistry and Engineering, Ministry of Education and College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, P.R China.

This study is the first report on production and characterization of the enzyme from an species. A 4.2-fold increase in the extracellular protease (called L9T) production from L9 was achieved through one factor at-a-time approach and response surface methodological optimization. L9 protease exhibited a unique protein band with a mass of 25.9 kDa upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This novel protease was active over a range of pH (4-13), temperatures (30-80 oC) and salt concentrations (0-220 g/L), with the maximal activity observed at pH 7, 70 oC and 20 g/L NaCl. Proteolytic activity was upgraded in the presence of Ag+, Ca2+ and Sr2+, but was totally suppressed by 5 mM phenylmethylsulfonyl fluoride which suggests that this enzyme belongs to the serine protease family. L9 protease was resistant to certain common organic solvents and surfactants; particularly, 5 mM Tween 20 and Tween 80 improved the activity by 63 and 15%, respectively. More importantly, L9 protease was found to be effective in dehairing of goatskins, cowhides and rabbit-skins without damaging the collagen fibers. These properties confirm the feasibility of L9 protease in industrial applications, especially in leather processing.
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http://dx.doi.org/10.4014/jmb.2108.08037DOI Listing
November 2021

Characterization of Structural and Physicochemical Properties of an Exopolysaccharide Produced by sp. F2 From Fermented Soya Beans.

Front Microbiol 2021 29;12:744007. Epub 2021 Oct 29.

College of Biomass Science and Engineering, Sichuan University, Chengdu, China.

The present study sought to isolate a novel exopolysaccharide (EPS-F2) from sp. F2 through ethanol precipitation, anion-exchange, and gel-filtration chromatography and characterize the physicochemical properties by spectral techniques. EPS-F2 was identified as a neutral homo-exopolysaccharide composed of only glucose with a high molecular weight of 1.108 × 10 g/mol. It contained →6)-α-D-Glc-(1→ linkage in the main chain and →3, 6)-α-D-Glc-(1→ branch chain). Moreover, EPS-F2 possessed excellent thermal stability (266.6°C), water holding capacity (882.5%), oil holding capacity (1867.76%), and emulsifying activity against various edible oils. The steady shear experiments exhibited stable pseudo plasticity under various conditions (concentrations, temperatures, and pHs). The dynamic oscillatory measurements revealed that EPS-F2 showed a liquid-like behavior at a low concentration (2.5%), while a solid-like behavior at high concentrations (3.0 and 3.5%). Overall, these results suggest that EPS-F2 could be a potential alternative source of functional additives and ingredients and be applied in food industries.
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http://dx.doi.org/10.3389/fmicb.2021.744007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8586432PMC
October 2021

Mechanism of Cr(VI) reduction by Lysinibacillus sp. HST-98, a newly isolated Cr (VI)-reducing strain.

Environ Sci Pollut Res Int 2021 Dec 30;28(46):66121-66132. Epub 2021 Jul 30.

College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China.

Facing the increasingly severe Cr(VI) pollution, bioreduction has proved to be an eco-friendly remediation method. An isolated strain identified as Lysinibacillus can relatively reduce Cr(VI) well. Even if the concentration of Cr(VI) increased to 250mg/L, the strain HST-98 could also grow and remove Cr(VI) well. After optimization of reaction conditions, the optimal pH, temperature, and electron donor are 8~9, 36°C, and sodium lactate, respectively. Coexisting metal ions such as Cu, Co, and Mn are beneficial to reduce Cr(VI), while Zn, Ni, and Cd are just the opposite. What is more, the mechanism of the reduction by the strain HST-98 is chiefly mediated by intracellular enzymes. After gene sequence homology blast and analysis, the genes and enzymes related to chromium metabolism in strain HST-98 have been annotated, which helps us to further understand the reduction mechanism of the strain HST-98. In general, Lysinibacillus sp. HST-98 is a potential candidate to repair the Cr(VI)-contaminated sites.
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http://dx.doi.org/10.1007/s11356-021-15424-xDOI Listing
December 2021

Structural elucidation and physicochemical characteristics of a novel high-molecular-weight fructan from halotolerant Bacillus sp. SCU-E108.

Food Chem 2021 Dec 30;365:130496. Epub 2021 Jun 30.

College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, PR China; Key Laboratory of Leather Chemistry and Engineering (Sichuan University), Ministry of Education, Chengdu 610065, PR China. Electronic address:

An exopolysaccharide, EPS-B108, was isolated from the fermented broth (with a yield of 11.3 g/L) of halotolerant Bacillus sp. SCU-E108 by ethanol precipitation, anion-exchange and gel-filtration chromatography, and well characterized by means of physical, chemical and spectral techniques. Data indicated that EPS-B108 was composed solely of fructose with a high molecular weight of 3.578 × 10 g/mol, and contained a β-(2 → 6)-linked d-Fruf backbone with a single β-d-Fruf at C-1 position. An irregular saccular- or cake-like shape was observed under the enlarged view. It showed no acute oral toxicity in mice, and had good thermal stability (242 °C), solubility in water (91.3%) and oil-holding capacity (1717.0%). Steady-shear flow and dynamical viscoelasticity of aqueous EPS-B108 solutions varied with the polymer concentration, shear rate and temperature, and were described by the Power-law model. Together, these findings support the further application of EPS-B108 as an alternative source of functional food additives and ingredients.
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http://dx.doi.org/10.1016/j.foodchem.2021.130496DOI Listing
December 2021

Optimization of fermentation conditions, purification and rheological properties of poly (γ-glutamic acid) produced by 1006-3.

Prep Biochem Biotechnol 2021 Jul 8:1-9. Epub 2021 Jul 8.

College of Biomass Science and Engineering, Sichuan University, Chengdu, P. R. China.

This study aimed to investigate the optimal fermentation condition, purification and rheological properties of extracellular polymers produced by 1006-3. An optimum temperature of 30.2 °C, inoculation amount of 6.1%, and pH of 8.2 were determined via Response Surface Methodology. The result of amino acid analysis and gel electrophoresis indicated that the obtained polymer contained only glutamic acid, with a wide molecular weight range. This polymer was finally determined as γ-PGA by infrared spectroscopy. The γ-PGA solution displayed a behavior of pseudoplastic non-Newtonian fluid with shear thinning properties, which can be described by the Ostward-de Waele power law model. The apparent viscosity of γ-PGA solution increased with the increase in its concentration from 1% to 10%. The deviation in pH from neutral value, and the addition of NaCl or MgCl can reduce the apparent viscosity of γ-PGA solution, and it was more sensitive to Mg than to Na addition. At the concentration of 4, 6, and 8%, γ-PGA solution showed predominantly viscous response in the range of 0.1-100 rad/s angular frequency (″>). These results indicated the potential application of the γ-PGA as a thickening agent.
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http://dx.doi.org/10.1080/10826068.2021.1941103DOI Listing
July 2021

Extraction Optimization and Evaluation of the Antioxidant and α-Glucosidase Inhibitory Activity of Polysaccharides from cv. Hangju.

Antioxidants (Basel) 2020 Jan 9;9(1). Epub 2020 Jan 9.

College of Food Science, Sichuan Agricultural University, Ya'an 625014, China.

In order to evaluate the antioxidant and α-glucosidase activities of polysaccharides from cv. Hangju (CMPs), the response surface methodology was applied to optimize the parameters for extraction progress of CMPs by ultrasound, with heat reflex extraction (HRE) performed as the control. The difference in the physicochemical properties of polysaccharides obtained by the two methods were also investigated. The maximum yields (8.29 ± 0.18%) of polysaccharides extracted by ultrasonic assisted extraction (UAE) were obtained under the optimized conditions of ultrasonic power 501 W, extraction time 19 min, and ratio of liquid-to-raw material 41 mL/g. Polysaccharides extracted by UAE possessed lower protein contents (2.56%) and higher uronic acids contents (7.08%) and low molecular weight fractions than that by HRE. No significant differences were found in monosaccharide composition and Fourier transform infrared (FT-IR) spectra of polysaccharides extracted by UAE and HRE, while polysaccharides by UAE possessed stronger antioxidant and α-glucosidase inhibitory activities. Therefore, UAE was an efficient way to obtain CMPs.
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http://dx.doi.org/10.3390/antiox9010059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7023348PMC
January 2020

Optimization, characterization and rheological behavior study of pectin extracted from chayote (Sechium edule) using ultrasound assisted method.

Int J Biol Macromol 2020 Mar 9;147:688-698. Epub 2020 Jan 9.

College of Food Science, Sichuan Agricultural University, Ya'an 625014, China. Electronic address:

Pectin is one of high-value functional food ingredients. Better knowledge of properties of chayote pectin would help to promote the application of the chayote as a pectin source. In this study, ultrasound-assisted extraction (UAE) was used to extract chayote pectin. The extraction parameters were optimized by a Box-Behnken response surface design. The highest yield (6.19%) was obtained at a liquid/solid ratio of 50 mL/g, ultrasonic temperature of 70 °C and ultrasonic time of 40 min as optimized extraction conditions. The chemical properties, spectral information and rheological properties of pectin extracted with UAE under the optimum conditions (PEUO) were measured and the results indicated that the PEUO exhibited a low degree of esterification, high molar mass (2.47 × 10 g/mol) and suitable foaming capacity. The PEUO featured a stronger antioxidant capacity compared to commercially apple pectin and the PEUO solutions (1%, 2%, 3% and 5%) showed a non-Newtonian behavior. Hence, PEUO may provide beneficial characteristics to find use in food industry.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.01.055DOI Listing
March 2020

Preparation and characterization of indicator films from carboxymethyl-cellulose/starch and purple sweet potato (Ipomoea batatas (L.) lam) anthocyanins for monitoring fish freshness.

Int J Biol Macromol 2020 Jan 6;143:359-372. Epub 2019 Dec 6.

College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan, China. Electronic address:

A novel indicator film from carboxymethyl-cellulose (CMC)/starch (S) and purple sweet potato anthocyanins (PSPA) was prepared and characterized. The Fourier transform infrared spectroscopic (FT-IR) analysis indicated that new interaction were generated between the components of the film, and the scanning electron microscopic (SEM) and X-ray diffraction spectra (XRD) showed that PSPA was well dispersed in CMC and starch-based film. The results from differential scanning calorimetric (DSC) analysis revealed that the novel film had increased melting temperature. The addition of PSPA into the film resulted in the increase of tensile strength but the decrease of elongation at break and moisture content. The analysis of color change demonstrated that the film color was changed from red to blue and green when exposed to different pH or ammonia. In their application trial, the SCA film was used as labels to monitor the freshness of fish stored at 20 °C, and the results showed that the color of the film was changed from red to blue when the fish became spoiled. The observation was consistent with the TVB-N value, which was higher than the set limit (20 mg/100 g). Hence, the novel indicator film could be used as intelligent food packaging to monitor fish freshness.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.12.024DOI Listing
January 2020
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