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Enzyme and Microbial Technology

Ke Zhang, Limei Chen, Jianmin Liu, Feng Gao, Ronglin He, Wuxi Chen, Wei Guo, Shulin Chen, Demao Li
Schizochytrium is a microalgae-like fungus and is widely used for producing docosahexaenoic acid (DHA). It is also a promising source of squalene and carotenoids. However, few fermentation strategies are available in enhancing squalene and carotenoid content in Schizochytrium. This study showed that butanol addition had multiple effects on Schizochytrium limacinum B4D1. First, butanol addition altered the lipid content of cells. Second, 6g/L of butanol decreased the proportion of DHA by nearly 40%. Third, the squalene content increased 31-fold in the presence of 6g/L butanol...
July 2017: Enzyme and Microbial Technology
Ming-Hua Liang, Shi-Shui Zhou, Jian-Guo Jiang
HBscFv-IFNγ, a fusion protein constructed by fusing γ-interferon (IFNγ) with an antibody fragment HBscFv for the purpose of targeted delivery of the cytokine IFNγ, was designed in order to enhance its therapeutic efficacy through increasing its hepatoma localization. HBscFv and IFNγ were connected into HBscFv-IFNγ by the linker (Gly4Ser)3, and then the multicopy recombinant plasmids pPICZαA/(HBscFv-IFNγ)1,2,4 were constructed and transformed into Komagatella (Pichia) pastoris X33. The engineering strain X4, which had much higher copy number and could secretively express HBscFv-IFNγ, was screened from transformed X33 by qPCR...
July 2017: Enzyme and Microbial Technology
Christian Hutterer, Gerhard Kliba, Manuel Punz, Karin Fackler, Antje Potthast
The high-yield separation of polymeric parts from wood-derived lignocellulosic material is indispensable in biorefinery concepts. For the separation of cellulose and xylan from hardwood paper pulps to obtain pulps of high cellulose contents, simple alkaline extractions were found to be the most suitable technology, although having certain limitations. These are embodied by residual alkali resistant xylan incorporated in the pulp matrix. Further purification in order to produce pure cellulose with a low uniformity could be achieved selectively degrading residual xylan and depolymerizing the cellulose macromolecules by xylanase and cellulase...
July 2017: Enzyme and Microbial Technology
Nilay Ildiz, Ayse Baldemir, Cevahir Altinkaynak, Nalan Özdemir, Vedat Yilmaz, Ismail Ocsoy
Herein, we report the production of novel organic-inorganic nanobio-catalytic and antimicrobial agents called "nanosnowball" (NSBs) with a rational design and elucidate the increase in the catalytic and antimicrobial activities. The NSBs resemble to guelder rose were formed of the extract of Viburnum opulus (VO) as the organic component and copper (II) ions (Cu(2+)) as the inorganic component. The effects of the VO extract and Cu(2+) concentrations on the morphology of NSBs were systematically examined and characterized with several techniques such as SEM, FT-IR, EDX and XRD...
July 2017: Enzyme and Microbial Technology
Muamer Dervisevic, Esma Dervisevic, Mehmet Senel, Emre Cevik, Huseyin Bekir Yildiz, Pınar Camurlu
Herein, an electrochemical urea sensing bio-electrode is reported that has been constructed by firstly electropolymerizing 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline monomer (SNS-Aniline) on Pencil Graphite Electrode (PGE), then modifying the polymer coated electrode surface with di-amino-Ferrocene (DAFc) as the mediator, and lastly Urease enzyme through glutaraldehyde crosslinking. The effect of pH, temperature, polymer thickness, and applied potential on the electrode current response was investigated besides performing storage and operational stability experiments with the interference studies...
July 2017: Enzyme and Microbial Technology
Hong Pan, Lihua Zhang, Xun Li, Daoyi Guo
The fatty acid methyl esters and fatty acid ethyl esters are known as biodiesels which are considered to be renewable, nontoxic and biodegradable biofuels. However, the conventional biodiesels show a high crystallization temperature which is one of the most critical obstacles against the widespread biodiesel usage. The high crystallization temperature of biodiesel can be reduced by replacing the methyl or ethyl ester with an isopropyl moiety. Here we report on a strategy to establish biosynthesis of the fatty acid isopropyl esters(FAIPEs) from the simple substrate glucose in Escherichia coli with heterologous coexpression of atoB encoded acetyl-CoA acetyltransferase and atoAD encode acetoacetyl-CoA transferase from E...
July 2017: Enzyme and Microbial Technology
Abid Hussain, Frédérique Matteau Lebrun, Boris Tartakovsky
This study evaluated performance of an upflow membraneless microbial electrolysis cell (MEC) with flow-through electrodes for wastewater treatment. First, methane production and COD removal were evaluated in continuous flow experiments carried out using synthetic and municipal wastewater. A 29-75% increase in methane production was observed under bioelectrochemical conditions as compared to an anaerobic control. Next, simultaneous removal of COD and nitrogen was studied under microaerobic conditions created by continuous air injection to the anodic compartment of the MEC...
July 2017: Enzyme and Microbial Technology
Dong He, Wen Luo, Zhiyuan Wang, Pengmei Lv, Zhenhong Yuan, Shaowei Huang, Jingliang Xv
Directed evolution has been proved an effective way to improve the stability of proteins, but high throughput screening assays for directed evolution with simultaneous improvement of two or more properties are still rare. In this study, we aimed to establish a membrane-blot assay for use in the high-throughput screening of Rhizomucor miehei lipases (RMLs). With the assistance of the membrane-blot screening assay, a mutant E47K named G10 that showed improved thermal stability was detected in the first round of error-prone PCR...
July 2017: Enzyme and Microbial Technology
Chao Wang, Hong-Bin Zhang, Meng-Qi Li, Xue-Qin Hu, Yao Li
Dextrans with distinct molecular size and structure are increasingly being used in the food and pharmaceutical industries. Dextran is produced by dextransucrase (DSR, EC2.4.5.1), which is produced by Leuconostoc mesenteroides. DSR belongs to glycosyl hydrolase family (GH70) and synthesizes branched α-glucan (dextran) with both 5% α(1-3) and 95% α(1-6) glycosidic linkages. The DSR gene dex-YG (Genebank, Accession No. DQ345760) was cloned from the wild strain Leuconostoc mesenteroides 0326. This study generated a series of C-terminally truncated variants of dextransucrase and substituting the amino-acid residues in the active site of DSR...
July 2017: Enzyme and Microbial Technology
Jianhua Guo, Bing-Jie Ni, Xiaoyu Han, Xueming Chen, Philip Bond, Yongzhen Peng, Zhiguo Yuan
Activated sludge contains highly complex microbial communities, which play crucial roles in pollutant removal performance in wastewater treatment plants (WWTPs). Metagenomic sequencing was applied to characterize microbial community and functional profiles within activated sludge from a full-scale municipal WWTP carrying out simultaneous nitrogen and phosphorous removal (SNPR). We applied the assembled contigs (N90 of 591bp) and predicted genes to conduct taxonomic and function annotations, respectively. Results revealed the extraordinary microbial diversity of activated sludge, which included detection of minority populations that are difficult to be explored by traditional molecular methods...
July 2017: Enzyme and Microbial Technology
Laxmi Prasad Thapa, Sang Jun Lee, Chulhwan Park, Seung Wook Kim
In this study, L-lactic acid production was investigated from metabolically engineered strain of E. aerogenes ATCC 29007. The engineered strain E. aerogenes SUMI01 (Δpta) was generated by the deletion of phosphate acetyltransferase (pta) gene from the chromosome of E. aerogenes ATCC 29007 and deletion was confirmed by colony PCR. Under the optimized fermentation conditions, at 37°C and pH 6 for 84h, the L-lactic acid produced by engineered strain E. aerogenes SUMI01 (Δpta) in flask fermentation using 100g/L mannitol as the carbon source was 40...
July 2017: Enzyme and Microbial Technology
Jianfeng Wang, Zhongmei Liu, Zhemin Zhou
Chelating of pullulanases onto nickel (II)-modified magnetic nanoparticles results in one-step purification and immobilization of pullulanase, and facilitates the commercial application of pullulanase in industrial scale. To improve the catalytic behavior, especially the operational stability, of the nanocatalyst in consecutive batch reactions, we prepared various iminodiacetic acid-modified magnetic nanoparticles differed in surface polarity and spacer length, on which the His6-tagged pullulanases were chelated via nickel ions, and then studied the correlation between the MNPs surface property and the corresponding catalyst behavior...
June 2017: Enzyme and Microbial Technology
Sakthi Kumaran Palaniswamy, Vijayalakshmi Govindaswamy
We report here, for the first time, a zymogram technique designed for rapid screening of feruloyl esterase using ethyl ferulate as enzyme substrate and casein precipitation as enzyme activity indicator.
June 2017: Enzyme and Microbial Technology
Kuan-Ju Liu
Enzymatic syntheses of oligosaccharide fatty acid esters are important owing to their wide range of industrial applications in the food, cosmetic, and pharmaceutical industries. Transesterification of isomaltotriose and palmitic acid vinyl ester, catalyzed by the metalloprotease thermolysin, was performed in organic solvents. The process parameters (reaction time and temperature) were optimized to achieve the highest yield of isomaltotriose palmitate (IP). The water content of the reaction system played a key role in the acylation of isomaltotriose...
June 2017: Enzyme and Microbial Technology
Hongdan Zhang, Shubin Wu, Jun Xie
The different physical and chemical properties of lignin might have various effects on the enzymatic hydrolysis of lignocellulosic substrates. In this study, the influence of lignin on enzymatic digestibility of cellulose was assessed. Addition of 20% (4g/L) isolated enzymatic lignin (lignin 2 and 3) and kraft lignin (lignin 4) resulted in 5-20% drop of glucose yield, depending on lignin sources. The inhibitory effect of lignin was abated as the enzyme loading increased from 10 to 20FPU/g dry substrate. However, the increasing lignin amount to 40% (8g/L) did not appear to further decrease the cellulose hydrolysis efficiency...
June 2017: Enzyme and Microbial Technology
Yongqiang Zhu, Lidan Ye, Zhaofeng Chen, Weijiang Hu, Yanghui Shi, Jianbo Chen, Chenfei Wang, Yong Li, Weifeng Li, Hongwei Yu
The physiological role of Coenzyme Q10 (CoQ10) as an electron carrier suggests its association with redox potential. Overexpression of glyceraldehyde-3-phosphate dehydrogenase type I (gapA-1) in Rhodobacter sphaeroides elevated the NADH/NAD(+) ratio and meanwhile enhanced the CoQ10 content by 58%, but at the sacrifice of biomass. On the other hand, Vitreoscilla hemoglobin was heterologously expressed to enhance the oxygen uptake ability of the cells, leading to 127% improvement of biomass. Subsequent coexpression of gapA-1 and vgb resulted in a CoQ10 titer of 83...
June 2017: Enzyme and Microbial Technology
Sun-Ki Kim, Jung-Hyun Jo, Yong-Cheol Park, Yong-Su Jin, Jin-Ho Seo
Spermidine is a polyamine compound exhibiting important biological activities, such as increasing lifespan, inflammation reduction, and plant growth control. As such, many applications of spermidine as a bio-modulating agent are anticipated. However, sustainable and scalable production of spermidine has not been achieved yet. Therefore, construction of a spermidine production system using Saccharomyces cerevisiae was attempted in this study. In order to secrete spermidine into fermentation broth, TPO1 coding for the polyamine transporter was overexpressed in an engineered S...
June 2017: Enzyme and Microbial Technology
Huijuan Xu, Cuiyi Liang, Zhenhong Yuan, Jingliang Xu, Qiang Hua, Ying Guo
Bioconversion of CO/syngas to produce ethanol is a novel route in bioethanol production, which can be accomplished by some acetogens. Specific culture vessels and techniques are needed to cultivate these microorganisms since they are anaerobic and substrates are gaseous. In this work, gas-sampling bag was applied as a gas-cultivation system to study CO/syngas bioconversion by Clostridium autoethanogenum and was demonstrated to be efficient because of its flexibility and excellent ability to maintain the headspace atmosphere...
June 2017: Enzyme and Microbial Technology
Liqin He, Sung-Hoon Park, Nguyen Dang Hai Dang, Hoa Xo Duong, Thi Phung Cac Duong, Phuong Lan Tran, Jong-Tae Park, Li Ni, Kwan-Hwa Park
We characterized ramie leaf β-amylase, and determined its thermostability and kinetic parameters. The enzyme was purified 53-fold using ammonium sulfate fractionation (40-60% saturation), anion exchange chromatography on DEAE-cellulose and gel permeation chromatography on Superdex-200. The purified enzyme was identified as β-amylase with molecular mass of 42kD. The enzyme displayed Km and kcat values for soluble potato starch of 1.1mg/mL and 7.8s(-1), respectively. The enzyme had a temperature optimum of 65°C, and its activity at 70°C was 92% of that at the optimal temperature after a 15-min incubation...
June 2017: Enzyme and Microbial Technology
Nafiseh Bakhshi, Sabihe Soleimanian-Zad, Mahmoud Sheikh-Zeinoddin
Currently, screening of microbial biosurfactants (BSs) is based on their equilibrium surface tension values obtained using static surface tension measurement. However, a good surfactant should not only have a low equilibrium surface tension, but its dynamic surface tension (DST) should also decrease rapidly with time. In this study, screening of BSs produced by Lactobacillus plantarum subsp. plantarum PTCC 1896 (probiotic) was performed based on their DST values measured by Wilhelmy plate tensiometry. The relationship between DST and structural and functional properties (anti-adhesive activity) of the BSs was investigated...
June 2017: Enzyme and Microbial Technology
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