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Enzyme and Microbial Technology

Kanti N Mihooliya, Jitender Nandal, Laxmi Swami, Himanshu Verma, Lipsy Chopra, Debendra K Sahoo
l-asparaginase is a pharmaceutically and industrially important enzyme as it has potential to treat different cancers and inhibit acrylamide formation in fried and baked food products. In the present study, an attempt was made to screen for new and novel l-asparaginase producers using a widely applied phenol red and bromothymol blue (BTB)(1) dye-based plate assay. Screening of four different soil samples for l-asparaginase producers resulted in the isolation of three new potential l-asparaginase producing bacteria...
December 2017: Enzyme and Microbial Technology
Hyoju Kim, Hyun-Soo Lee, Haeseong Park, Dae-Hee Lee, Eckhard Boles, Donghwa Chung, Yong-Cheol Park
Inefficient transport of xylose into Saccharomyces cerevisiae is a major hurdle for production of xylitol, a natural sweetener with five carbons. To facilitate the xylose transport and hence increase xylose conversion to xylitol, the araE gene encoding an arabinose:H(+) symporter (AraE) from Bacillus subtilis and the XYL1 gene from Scheffersomyces stipitis were expressed in Saccharomyces cerevisiae EBY.VW4000, a hxt null mutant. The resulting strain of EXHA exhibited 4.1 fold increases in xylose consumption rate and xylitol productivity, relative to the control strain without AraE...
December 2017: Enzyme and Microbial Technology
Khadijeh Moradi, Seyedeh Akram Shirdel, Masoumeh Shamsi, Vahab Jafarian, Khosrow Khalifeh
Chondroitin Sulfate Proteoglycans (CSPGs) are the main inhibitors for axon regeneration after damaging of Central Nervous System (CNS). Chondroitinase ABC I (cABC I) can degrade CSPGs by removing chondroitin and dermatan sulfate side chains from proteoglycans. Hence, it may be considered as an attractive candidate in biomedicine. For practical applications of this enzyme, increasing the effective circulating level and reducing the number and volume of injections for patients is one of the main concerns which is directly related to conformational stability and catalytic efficiency of the enzyme...
December 2017: Enzyme and Microbial Technology
Radhakrishna Shetty, Mike Vestergaard, Flemming Jessen, Per Hägglund, Verena Knorr, Peter Koehler, H S Prakash, Timothy John Hobley
Gluten free products have emerged during the last decades, as a result of a growing public concern and technological advancements allowing gluten reduction in food products. One approach is to use gluten degrading enzymes, typically at low or ambient temperatures, whereas many food production processes occur at elevated temperature. We present in this paper, the discovery, cloning and characterisation of a novel recombinant thermostable gluten degrading enzyme, a proline specific prolyl endoprotease (PEP) from Sphaerobacter thermophiles...
December 2017: Enzyme and Microbial Technology
Samir R Dedania, Manisha J Patel, Dijit M Patel, Rekha C Akhani, Darshan H Patel
D-Psicose (D-ribo-2-hexulose or D-allulose), an epimer of D-fructose is considered as a rare low-calorie sugar displaying important physiological functions. Enzymatic production using ketose 3-epimerases is the feasible process for the production of D-Psicose. However, major drawbacks in application of ketose 3-epimerases are bioconversion efficiency and reusability of the enzyme. We have attempted immobilization of ketose 3-epimerases from Agrobacterium tumefaciens (agtu) D-psicose 3-epimerase (DPEase) on graphene oxide...
December 2017: Enzyme and Microbial Technology
Zheng-Yu Yan, Qing-Qing Du, Dong-Yu Wan, Hang Lv, Zhi-Ran Cao, Sheng-Mei Wu
Quantum dots (QDs) are semiconductor nanoparticles (NPs) that offer valuable functionality for cellular labeling, drug delivery, solar cells and quantum computation. In this study, we reported that CdSe QDs could be bio-synthesized in Bacillus licheniformis. After optimization, the obtained CdSe QDs exhibited a uniform particle size of 3.71±0.04nm with a maximum fluorescence emission wavelength at 550nm and the synthetical positive ratio can reach up to 87%. Spectral properties, constitution, particle sizes and crystalline phases of the CdSe QDs were systematically and integrally investigated...
December 2017: Enzyme and Microbial Technology
Ya-Jun Wang, Bin-Bin Ying, Wei Shen, Ren-Chao Zheng, Yu-Guo Zheng
t-Butyl 6-cyano-(3R,5R)-dihydroxyhexanoate ((3R,5R)-1b) is a valuable chiral synthon of atorvastatin calcium. A novel NADPH-specific aldo-keto reductase (AKR) was identified from a thermotolerant yeast Kluyveromyces marxianus ZJB14056 by genome database mining, displaying t-butyl 6-cyano-(5R)-hydroxy-3-oxohexanoate ((5R)-1a) reducing activity and moderate diastereoselectivity (dep∼80.5%). Molecular homology modeling and docking studies demonstrated that the side chain of Trp297 blocks binding of (5R)-1a to KmAKR...
December 2017: Enzyme and Microbial Technology
Shuguang Wang, Debing Zheng, Lingyu Yin, Fei Wang
Cross-linked enzyme aggregates (CLEAs) have emerged as an interesting biocatalyst design for enzyme immobilization. However, the commercialization of CLEAs is often hampered by their shortcomings, such as poor-controlled particle size, low activity and sticky characteristic. In order to overcome these drawbacks, five nanoparticles (NPs) (nano-TiO2, nano-MgO, nano-Ni, nano-Cu and nano-Fe3O4) were used to improve CLEAs activity and structure in this study. Results showed that moderate dosage of nano-TiO2 addition increased CLEAs activity, and the most increment was 15...
December 2017: Enzyme and Microbial Technology
Seung-Hee Nam, Jin-A Ko, Woojin Jun, Young-Jung Wee, Marie K Walsh, Kwang-Yeol Yang, Jin-Ho Choi, Jon-Bang Eun, Jeong Choi, Young-Min Kim, Songhee Han, Thi Thanh Hanh Nguyen, Doman Kim
Chlorogenic acid, a major polyphenol in edible plants, possesses strong antioxidant activity, anti-lipid peroxidation and anticancer effects. It used for industrial applications; however, this is limited by its instability to heat or light. In this study, we for the first time synthesized chlorogenic acid glucoside (CHG) via transglycosylation using dextransucrase from Leuconostoc mesenteroides and sucrose. CHG was purified and its structure determined by nuclear magnetic resonance and matrix-associated laser desorption ionization-time-of-flight mass spectroscopy...
December 2017: Enzyme and Microbial Technology
Mounia Merabet-Khelassi, Amna Zaidi, Louisa Aribi-Zouioueche
Herein, we report an efficient enantioselective cleavage of the acyl-moity of some secondary benzylic acetate derivatives catalyzed by lipase B from Candida antarctica (CAL-B) in the presence of triethylamine, as additive, in non aqueous media. The influence of the hydrophobicity of two solvent, the basicity of three amines and the amount of CAL-B were studied in the presence/absence of molecular sieves 4Å. The best results in term of selectivity are achieved using the triethylamine as basic additive and in that case, the reactivity is only best at low conversion...
December 2017: Enzyme and Microbial Technology
Bo-Liang Gong, Run-Qian Mao, Yue Xiao, Mei-Lu Jia, Xiao-Lin Zhong, Yan Liu, Pei-Lin Xu, Gang Li
A new protease gene (pro1437)was separated from an oil-polluted Mud flat metagenomic library. Pro1437 belongs to a peptidase M48 superfamily according to the results of sequence analysis, and it showed very low identities compared to other known proteases or peptidases. The error-prone PCR was used to introduce random mutations and improve the expression of pro1437. After two rounds of mutagenesis and screening, a mutant (Pro2T21) with a 6.6-fold higher activity and a 4.8-fold higher expression level than Pro1437 was obtained...
November 2017: Enzyme and Microbial Technology
Line Munk, Mogens Larsen Andersen, Anne S Meyer
Laccases (EC catalyse removal of an electron and a proton from phenolic hydroxyl groups, including phenolic hydroxyls in lignins, to form phenoxy radicals during reduction of O2. We employed electron paramagnetic resonance spectroscopy (EPR) for real time measurement of such catalytic radical formation activity on three types of lignin (two types of organosolv lignin, and a lignin rich residue from wheat straw hydrolysis) brought about by two different fungal laccases, derived from Trametes versicolor (Tv) and Myceliophthora thermophila (Mt), respectively...
November 2017: Enzyme and Microbial Technology
Yilan Wu, Xianhua Sun, Xianli Xue, Huiying Luo, Bin Yao, Xiangming Xie, Xiaoyun Su
Vast interest exists in developing T. reesei for production of heterologous proteins. Although rich genomic and transcriptomic information has been uncovered for the T. reesei secretion pathway, little is known about whether engineering its key components could enhance expression of a heterologous gene. In this study, snc1, a v-SNARE gene, was first selected for overexpression in T. reesei. In engineered T. reesei with additional copies of snc1, the Aspergillus niger glucose oxidase (AnGOD) was produced to a significantly higher level (2...
November 2017: Enzyme and Microbial Technology
Razia Tajwar, Saher Shahid, Rehan Zafar, Muhammad Waheed Akhtar
Xylanase XynB of the hyperthermophile Thermotoga maritima, which belongs to glycoside hydrolase family 10 (GH10), does not have an associated carbohydrate binding module (CBM) in the native state. CBM6 and CBM22 from a thermophile Clostridium thermocellum were fused to the catalytic domain of XynB (XynB-C) to determine the effects on activity and other properties. XynB-B22C and XynB-CB22, produced by fusing CBM22 to the N- and C-terminal of XynB-C, showed 1.7- and 3.24-fold increase in activity against the insoluble birchwood xylan, respectively...
November 2017: Enzyme and Microbial Technology
Hadjer Zaak, Laura Fernandez-Lopez, Cristina Otero, Mohamed Sassi, Roberto Fernandez-Lafuente
Phospholipase Lecitase Ultra (LU) and lipase from Thermomyces lanuginosus (TLL) have been immobilized under conditions that favor either enzyme crowding or enzyme dispersion. Highly loaded LU was more stable than low loaded biocatalyst under all studied conditions. Using TLL, the results depended on the inactivation conditions, e.g., crowding was positive at pH 5 and negative at pH 7. Then, all preparations were treated with glutaraldehyde (Glu), polyethyleneimine (PEI) or sequentially with Glu and PEI. These treatments may permit to stabilize the physically immobilized lipases by avoiding enzyme desorption via intermolecular crosslinking...
November 2017: Enzyme and Microbial Technology
Yangyang Zheng, Qianqian Yuan, Xiaoyan Yang, Hongwu Ma
Poly-(3-hydroxybutyrate) (P3HB) is a promising biodegradable plastic synthesized from acetyl-CoA. One important factor affecting the P3HB production cost is the P3HB yield. Through flux balance analysis of an extended genome-scale metabolic network of E. coli, we found that the introduction of non-oxidative glycolysis pathway (NOG), a previously reported pathway enabling complete carbon conservation, can increase the theoretical carbon yield from 67% to 89%, equivalent to the theoretical mass yield from 0.48g P3HB/g glucose to 0...
November 2017: Enzyme and Microbial Technology
Jan-Stefan Völler, Tuyet Mai Thi To, Hernan Biava, Beate Koksch, Nediljko Budisa
Global substitution of canonical amino acids (cAAs) with noncanonical (ncAAs) counterparts in proteins whose function is dependent on post-translational events such as cofactor binding is still a methodically challenging and difficult task as ncAA insertion generally interferes with the cofactor biosynthesis machinery. Here, we report a technology for the expression of fully substituted and functionally active cofactor-containing hemeproteins. The maturation process which yields an intact cofactor is timely separated from cAA→ncAA substitutions...
November 2017: Enzyme and Microbial Technology
Faseela Hamza, Amogh Vaidya, Mugdha Apte, Ameeta Ravi Kumar, Smita Zinjarde
Controlling disease outbreaks is a major challenge in aquaculture farms and conventional methods are often ineffective. Nutritional supplementation and probiotic preparations help in reducing severity of such infections. The generally regarded as safe yeast (Yarrowia lipolytica) was used in the current study. A marine strain of Y. lipolytica exhibited tolerance towards sodium selenite and formed cell associated selenium nanoparticles (SeNPs). The synthesized nanoparticles were characterized by UV-vis spectroscopy, X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FE-SEM) observations...
November 2017: Enzyme and Microbial Technology
Abdullah Al Loman, Lu-Kwang Ju
Soybean is well known for its high-value oil and protein. Carbohydrate is, however, an underutilized major component, representing almost 26-30% (w/w) of the dried bean. The complex soybean carbohydrate is not easily hydrolyzable and can cause indigestibility when included in food and feed. Enzymes can be used to hydrolyze the carbohydrate for improving soybean processing and value of soybean products. Here the enzyme-based processing developed for the following purposes is reviewed: hydrolysis of different carbohydrate-rich by/products from soybean processing, improvement of soybean oil extraction, and increase of nutritional value of soybean-based food and animal feed...
November 2017: Enzyme and Microbial Technology
Chao Guo, Zhong-Liu Wu
Cytochrome P450 enzymes are versatile biocatalysts with great potential in biotechnology. A new bacterial P450 was identified from the genome of Rhodococcus wratislaviensis NBRC 100605 and annotated as CYP108N7. The enzyme accepted the ferredoxin and ferredoxin reductase from spinach as surrogate redox partners for improved electron transfer efficiency. It was heterologous expressed in Escherichia coli together with the redox partners and a glucose dehydrogenase which supplied the reduced cofactor NADPH. The resulting whole-cell biocatalyst catalyzed a variety of reactions including sulfoxidation, epoxidation, hydroxylation, demethylation and dehalogenation...
November 2017: Enzyme and Microbial Technology
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