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Enzyme and Microbial Technology

Songhee Han, Thi Thanh Hanh Nguyen, Jaewon Hur, Nahyun M Kim, Seong-Bo Kim, Kyeong-Hwan Hwang, Young-Hwan Moon, Choongil Kang, Byoungsang Chung, Young-Min Kim, Tae Sung Kim, Jun-Seong Park, Doman Kim
Astragalin (kaempferol-3-O-β-d-glucopyranoside, Ast) is a kind of flavonoid known to have anti-oxidant, anti-HIV, anti-allergic, and anti-inflammatory effects. It has low solubility in water. In this study, novel astragalin galactosides (Ast-Gals) were synthesized using β-galactosidase from Bacillus circulans and reaction conditions were optimized to increase the conversion yield of astragallin. Purified Ast-Gal1 (11.6% of Ast used, w/w) and Ast-Gal2 (6.7% of Ast used, w/w) were obtained by medium pressure chromatography (MPLC) with silica C18 column and open column packed with Sephadex LH-20...
August 2017: Enzyme and Microbial Technology
Hyun-Myoung Cha, Jin-Hyuk Lim, Jung-Heum Yeon, Jeong-Min Hwang, Dong-Il Kim
Terminal sialic acids on N-glycan of recombinant human erythropoietin are very important for in vivo half-life, as this glycoprotein has three N-glycosylation sites. N-acetylglucosaminyltransferases I, II, IV, and V (i.e. Mgat1, Mgat2, Mgat4, and Mgat5) catalyze the formation of a glycan antennary structure. These enzymes display different reaction kinetics for a common substrate and generally show low expression in Chinese hamster ovary (CHO) cells. Therefore, genetic control of Mgat expression is an effective method to increase sialic acid contents by enhancing glycan antennarity...
August 2017: Enzyme and Microbial Technology
Zafar Ali, Lei Tian, Baoliang Zhang, Nisar Ali, Muhammad Khan, Qiuyu Zhang
The mesoporous yolk-shell nanoparticles (MYSNs), with a movable Fe3O4 core inside the hollow capsules, with two different morphologies (1) Fe3O4@SiO2@hollow@fibrous SiO2 (Yolk Shell-1) (2) Fe3O4@SiO2@hollow@mesoporousSiO2 (Yolk Shell-2) were fabricated as carriers for Candida rugosa lipase (CRL) immobilization, through a template-assistant selectively etching method. Firstly the hydrophilic Fe3O4 nanoparticles were synthesized according to the solvothermal method. Then, SiO2 shell was coated on the Fe3O4 nanoparticle surface by a sol-gel reaction...
August 2017: Enzyme and Microbial Technology
Xiaojian Ma, Lu Liu, Qingqing Li, Yunyun Liu, Li Yi, Lixin Ma, Chao Zhai
Laccases are oxidoreductase catalyze the oxidation of a wide range of substrates with oxygen as the electron acceptor. This report was aimed to the high-level expression of a laccase, CueO from Escherichia coli K12 in Pichia pastoris GS115 and its application on decolorization of synthetic dyes. The yacK gene coding CueO was cloned into an expression vector of Pichia pastoris, pHBM905BDM and expressed in a secretory form with Pichia pastoris GS115 as the host. The yield of the recombinant protein was 556mg/L with high-density fermentation and the enzyme activity was about 41,000U/L...
August 2017: Enzyme and Microbial Technology
Akiho Maruta, Mirei Yamane, Midori Matsubara, Shiho Suzuki, Masami Nakazawa, Mitsuhiro Ueda, Tatsuji Sakamoto
We previously reported that Fusarium oxysporum 12S produces two bifunctional proteins, FoAP1 and FoAP2, with α-d-galactopyranosidase (GPase) and β-l-arabinopyranosidase (APase) activities. The aim of this paper was to purify a third GPase, FoGP1, from culture supernatant of F. oxysporum 12S, to characterize it, and to determine its mode of action towards gum arabic. A cDNA encoding FoGP1 was cloned and the protein was overexpressed in Escherichia coli. Module sequence analysis revealed the presence of a GH27 domain in FoGP1...
August 2017: Enzyme and Microbial Technology
Ali Halalipour, Michael R Duff, Elizabeth E Howell, José I Reyes-De-Corcuera
The effect of high hydrostatic pressure (HHP) on the kinetics of thermal inactivation of xanthine oxidase (XOx) from bovine milk was studied. Inactivation of XOx followed pseudo-first-order kinetics at 0.1-300MPa and 55.0-70.0°C. High pressure up to at least 300MPa stabilized XOx at all the studied temperatures. The highest stabilization effect of HHP on XOx was at 200-300MPa at 55.0 and 58.6°C, and at 250-300MPa at 62.3-70.0°C. The stability of XOx increased 9.5 times at 300MPa and 70.0°C compared to atmospheric pressure at the same temperature...
August 2017: Enzyme and Microbial Technology
Behnam Tabatabai, AnithaChristy S Arumanayagam, Oluwatomisin Enitan, Arunmani Mani, Savithiry S Natarajan, Viji Sitther
Fremyella diplosiphon is a freshwater cyanobacterium that has great potential as a biofuel agent due to its ability to grow in low light intensity and acclimation to different wavelengths. To enhance its halotolerance for growth in 35gL(-1) sodium chloride (NaCl), plasmids harboring hemolysin B (hlyB) and malate dehydrogenase (mdh) genes were transformed into wild type F. diplosiphon (WT-Fd33). Electroporation-mediated overexpression of the genes resulted in two transformants, HSF33-1 and HSF33-2, with 9- and 20-fold increases in hlyB and mdh transcript levels...
August 2017: Enzyme and Microbial Technology
Samkelo Malgas, Mariska Thoresen, J Susan van Dyk, Brett I Pletschke
Cellulosic ethanol production relies on the biochemical (enzymatic) conversion of lignocellulose to fermentable sugars and ultimately to bioethanol. However, the cost of lignocellulolytic enzymes is a limiting factor in the commercialisation of this technology. This therefore necessitates the optimisation of lignocellulolytic enzyme cocktails through the elucidation of synergistic interactions between enzymes so as to improve lignocellulose hydrolysis and also lower protein loadings in these reactions. However, many factors affect the synergism that occurs between these lignocellulolytic enzymes, such as enzyme ratios, substrate characteristics, substrate loadings, enzyme loadings and time...
August 2017: 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
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