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Enzyme and Microbial Technology

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https://www.readbyqxmd.com/read/29108630/improved-thermostability-and-enzyme-activity-of-a-recombinant-phya-mutant-phytase-from-aspergillus-niger-n25-by-directed-evolution-and-site-directed-mutagenesis
#1
Zizhong Tang, Weiqiong Jin, Rong Sun, Yan Liao, Tianrun Zhen, Hui Chen, Qi Wu, Lin Gou, Chenlei Li
We previously constructed three recombinant phyA mutant strains (PP-NP(m)-8, PP-NP(ep)-6A and I44E/T252R-PhyA), showing improved catalytic efficiency or thermostability of Aspergillus niger N25 phytase, by error-prone PCR or site-directed mutagenesis. In this study, directed evolution and site-directed mutagenesis were further applied to improve the modified phytase properties. After one-round error-prone PCR for phytase gene of PP-NP(ep)-6A, a single transformant, T195L/Q368E/F376Y, was obtained with the significant improvements in catalytic efficiency and thermostability...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108629/spontaneous-pepsin-c-catalyzed-activation-of-human-pepsinogen-c-in-transgenic-rice-cell-suspension-culture-production-and-characterization-of-human-pepsin-c
#2
Md Reyazul Islam, Nan-Sun Kim, Jae-Wan Jung, Hyo-Boon Kim, So-Chon Han, Moon-Sik Yang
A human pepsinogen C (hPGC) gene was synthesized with rice-optimized codon usage and cloned into a rice expression vector containing the promoter, signal peptide, and terminator derived from the rice α-amylase 3D (Ramy3D) gene. In addition, a 6-His tag was added to the 3' end of the synthetic hPGC gene for easy purification. The plant expression vector was introduced into rice calli (Oryza sativa L. cv. Dongjin) mediated by Agrobacterium tumefaciens. The integration of the hPGC gene into the chromosome of the transgenic rice callus and hPGC expression in transgenic rice cell suspensions was verified via genomic DNA polymerase chain reaction amplification and Northern blot analysis...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108628/furfural-and-5-hydroxymethyl-furfural-degradation-using-recombinant-manganese-peroxidase
#3
Kelsey L Yee, Lauren E Jansen, Curtis A Lajoie, Michael H Penner, Lettie Morse, Christine J Kelly
Biomass pretreatment-derived degradation compounds, such as furfural and 5-hydroxymethyl-furfural (HMF), inhibit the growth of fermentation microorganisms that utilize biomass to produce fuels and chemicals. Here we report that recombinant manganese peroxidase (rMnP) produced from the yeast Pichia pastoris can degrade furfural and HMF making them less toxic to microorganisms. Treatment with rMnP or manganese(III) acetate reduced furfural and HMF concentrations in a dose-dependent manner. Furfural disappearance was accompanied by malonate disappearance and accumulation of four distinct degradation products...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108627/co-expression-of-an-alcohol-dehydrogenase-and-a-cyclohexanone-monooxygenase-for-cascade-reactions-facilitates-the-regeneration-of-the-nadph-cofactor
#4
Anna Kohl, Vishnu Srinivasamurthy, Dominique Böttcher, Johannes Kabisch, Uwe T Bornscheuer
The introduction of a three-enzyme cascade (comprising a cyclohexanone monooxygenase (CHMO), an alcohol dehydrogenase (ADH) and a lipase (CAL-A)) for the production of oligo-ε-caprolactone provided self-sufficiency with respect to NADPH-cofactor regeneration and reduced inhibiting effects on the central CHMO enzyme. For further optimization of cofactor regeneration, now a co-expression of CHMO and ADH in E. coli using a Duet™ vector was performed. This led to higher conversion values of the substrate cyclohexanol in whole-cell biocatalysis compared to an expression of both enzymes from two separate plasmids...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108626/enzymatic-esterification-of-eugenol-and-benzoic-acid-by-a-novel-chitosan-chitin-nanowhiskers-supported-rhizomucor-miehei-lipase-process-optimization-and-kinetic-assessments
#5
Fatin Myra Abd Manan, Nursyafreena Attan, Zainoha Zakaria, Aemi S Abdul Keyon, Roswanira Abdul Wahab
A biotechnological route via enzymatic esterification was proposed as an alternative way to synthesize the problematic anti-oxidant eugenyl benzoate. The new method overcomes the well-known drawbacks of the chemical route in favor of a more sustainable reaction process. The present work reports a Box-Behnken design (BBD) optimization process to synthesize eugenyl benzoate by esterification of eugenol and benzoic acid catalyzed by the chitosan-chitin nanowhiskers supported Rhizomucor miehei lipase (RML-CS/CNWs)...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108625/a-first-glycoside-hydrolase-family-50-endo-%C3%AE-1-3-d-glucanase-from-pseudomonas-aeruginosa
#6
Ping Yi, Qiaojuan Yan, Zhengqiang Jiang, Ling Wang
A novel β-1,3-glucanase gene (PaBglu50A) from Pseudomonas aeruginosa CAU 342A was cloned and expressed in Escherichia coli. The deduced amino acid sequence of PaBglu50A showed the highest identity of 34% with the β-agarase belonging to glycoside hydrolase (GH) family 50. The purified PaBglu50A had maximal activity at pH 5.5 and 45°C, respectively. It was stable in the range of pH 4.0-8.0 and at temperatures below 40°C. The Km and Vmax of PaBglu50A for curdlan and laminarin were 94.4mgml(-1) and 23.4μmolmin(-1)mg(-1), 3...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108624/rational-evolution-of-the-unusual-y-type-oxyanion-hole-of-rhodococcus-sp-cr53-lipase-lipr
#7
Belén Infanzón, Pablo H Sotelo, Josefina Martínez, Pilar Diaz
Rhodococcus sp CR-53 lipase LipR was the first characterized member of bacterial lipase family X. Interestingly, LipR displays some similarity with α/β-hydrolases of the C. antartica lipase A (CAL-A)-like superfamily (abH38), bearing a Y-type oxyanion hole, never found before among bacterial lipases. In order to explore this unusual Y-type oxyanion hole, and to improve LipR performance, two modification strategies based on site directed or saturation mutagenesis were addressed. Initially, a small library of mutants was designed to convert LipR Y-type oxyanion hole (YDS) into one closer to those most frequently found in bacteria (GGG(X))...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108623/displaying-a-recombinant-protein-on-flocs-self-produced-by-escherichia-coli-through-fused-expression-with-elongation-factor-ts
#8
Yoshihiro Ojima, Shota Nunogami, Masayuki Azuma, Masahito Taya
The utility of engineering flocculation is wildly recognized in applied and environmental microbiology. We previously reported self-produced flocculation of Escherichia coli cells by overexpressing the native bcsB gene that encodes a component of the cellulose synthesis pathway. Further experiments clarified that the spontaneous E. coli flocs were proteinous, and elongation factor Ts (Tsf) was the main component. In this study, we demonstrated successful expression of a fusion protein consisting of Tsf and green fluorescence protein (GFP) on E...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108622/encapsulation-of-lipase-within-metal-organic-framework-mof-with-enhanced-activity-intensified-under-ultrasound
#9
Shamraja S Nadar, Virendra K Rathod
The enzyme under lower-intensity ultrasonic irradiation leads to favorable conformational changes, thereby enhancing its activity. In this study, lipase activity was augmented upto 1.6-folds after ultrasonic treatment at 22kHz and 11.38Wcm(-2) for 25min. This highly activated lipase was encapsulated within zeolite imidazolate framework-8 (ZIF-8) as a metal-organic framework (MOF) material via facile one-step biomineralization method by simply mixing aqueous solution of 2-methylimidazole (13.3mmol) and zinc acetate (1...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/29108621/in-vitro-biosynthesis-of-3-mercaptolactate-by-lactate-dehydrogenases
#10
Christina Andreeßen, Natalie Wolf, Benedikt Cramer, Hans-Ulrich Humpf, Alexander Steinbüchel
3-Mercaptolactate (3ML) is an interesting mercapto compound with special regard to the biosynthesis of new polythioesters (PTEs). Unfortunately, this thioester analog of lactic acid is currently not commercially available. For this reason, we developed an in vitro biosynthesis pathway to convert cysteine to 3-mercaptopyruvate (3MPy), which is then rapidly and efficiently converted to 3ML by suitable lactate dehydrogenases (LDHs). As liver LDH from Rattus norvegicus (LDHRn) was previously described to Exhibit 3MPy reduction activity, in silico studies based on homology to LDHRn were performed and led to the identification of four potentially suitable bacterial LDH candidates from Escherichia coli (LDHEc), Corynebacterium glutamicum (LDHCg), Bacillus cereus (LDHBc) and Gloeobacter violaceus (LDHGv)...
January 2018: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/28899490/a-new-ph-indicator-dye-based-method-for-rapid-and-efficient-screening-of-l-asparaginase-producing-microorganisms
#11
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
https://www.readbyqxmd.com/read/28899489/enhanced-production-of-xylitol-from-xylose-by-expression-of-bacillus-subtilis-arabinose-h-symporter-and-scheffersomyces-stipitis-xylose-reductase-in-recombinant-saccharomyces-cerevisiae
#12
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
https://www.readbyqxmd.com/read/28899488/investigating-the-structural-and-functional-features-of-representative-recombinants-of-chondroitinase-abc-i
#13
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
https://www.readbyqxmd.com/read/28899487/discovery-cloning-and-characterisation-of-proline-specific-prolyl-endopeptidase-a-gluten-degrading-thermo-stable-enzyme-from-sphaerobacter-thermophiles
#14
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
https://www.readbyqxmd.com/read/28899486/immobilization-on-graphene-oxide-improves-the-thermal-stability-and-bioconversion-efficiency-of-d-psicose-3-epimerase-for-rare-sugar-production
#15
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
https://www.readbyqxmd.com/read/28899485/fluorescent-cdse-qds-containing-bacillus-licheniformis-bioprobes-for-copper-ii-detection-in-water
#16
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
https://www.readbyqxmd.com/read/28899484/rational-design-of-kluyveromyces-marxianus-zjb14056-aldo-keto-reductase-kmakr-to-enhance-diastereoselectivity-and-activity
#17
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
https://www.readbyqxmd.com/read/28899483/preparation-activity-and-structure-of-cross-linked-enzyme-aggregates-cleas-with-nanoparticle
#18
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
https://www.readbyqxmd.com/read/28899482/enzymatic-synthesis-of-chlorogenic-acid-glucoside-using-dextransucrase-and-its-physical-and-functional-properties
#19
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
https://www.readbyqxmd.com/read/28899481/cal-b-catalyzed-deacylation-of-benzylic-acetates-effect-of-amines-addition-comparison-of-several-approaches
#20
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
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