Influence of the metal ion on the enzyme activity and kinetics of PepA from Lactobacillus delbrueckii
Publication date: Available online 12 October 2017 Source:Enzyme and Microbial Technology Author(s): Jacob Ewert, Claudia Glück, Henry Strasdeit, Lutz Fischer, Timo Stressler The aminopeptidase A (PepA; EC 3.4.11.7) belongs to the group of metallopeptidases with two bound metal ions per subunit (M1M2(PepA)) and is specific for the cleavage of N-terminal glutamic (Glu) and aspartic acid (Asp) and, in low amounts, serine (Ser) residues. Our group recently characterized the first PepA from a Lactobacillus strain. However, the characterization was performed using synthetic para-nitroaniline substrates and not original pe...
Source: Enzyme and Microbial Technology - October 12, 2017 Category: Biotechnology Source Type: research

Microbial production of uracil by an isolated Methylobacterium sp. WJ4 using methanol
In this study, we report the production of uracil from methanol by an isolated methylotrophic bacterium, Methylobacterium sp. WJ4. The use of methanol as alternative carbon feedstock is attractive option in biotechnology. As a feedstock of biotechnological processes, methanol has distinct advantages over methane. This is not only due to physical and chemical considerations, but also to the properties of the pertinent organisms. Besides, with a wide array of biological activities and synthetic accessibility, uracil is considered as privileged structures in drug discovery. Uracil analogues have been applied to treatments of ...
Source: Enzyme and Microbial Technology - October 12, 2017 Category: Biotechnology Source Type: research

Heterologous expression and characterization of a putative glycoside hydrolase family 43 arabinofuranosidase from Clostridium thermocellum B8
Publication date: Available online 12 October 2017 Source:Enzyme and Microbial Technology Author(s): Brenda R. de Camargo, Nico J. Claassens, Eliane F. Noronha, Servé W.M. Kengen An extensive list of putative cellulosomal enzymes from C. thermocellum is now available in the public databanks, however, most of these remain unvalidated with regard to their activity and expression control mechanisms. This is particularly true of those enzymes putatively involved in hemicellulose deconstruction. Our research group has been working on mapping and characterization of glycoside hydrolases produced by C. thermocellum B8, th...
Source: Enzyme and Microbial Technology - October 12, 2017 Category: Biotechnology Source Type: research

A conserved residue of L-alanine dehydrogenase from Bacillus pseudofirmus, Lys-73, participates in the catalytic reaction through hydrogen bonding
In this study, recombinant OF4Ald and its mutants of five conserved residues were constructed, expressed in Escherichia coli, purified by His6-tag affinity column and gel filtration chromatography, structure homology modeling, and characterized. The purified protein OF4Ald displayed high specificity to L-alanine (15 U·mg−1) with an optimal temperature and pH of 40°C and 10.5, respectively. Enzymatic assay and activity staining in native gels showed that mutations at four conserved residue Arg-15, Lys-75, His-96 and Asp-269 (except residue Lys-73) resulted in a complete loss in enzymatic activity, which sig...
Source: Enzyme and Microbial Technology - October 12, 2017 Category: Biotechnology Source Type: research

Peroxidase Chemically Attached on Polymeric Micelle and Its Reaction with Phenolic Compounds
Publication date: Available online 29 September 2017 Source:Enzyme and Microbial Technology Author(s): Moo-Yeal Lee, Parnian Bigdelou, Kyung-Jin Hong, Kyoung-Ae Kim, Yoshitsune Shinya, Toshio Kajiuchi Horseradish peroxidase was chemically modified with comb-shaped polymaleic anhydride-alt-1-tetradecene (PMA-TD) in microemulsion systems to produce surface-active peroxidase that has capability to form micellar structures in aqueous solutions and can be concentrated at liquid/liquid interfaces without unfolding of the enzyme. For chemical modification oil-in-water (O/W) and water-in-oil (W/O) microemulsion systems composed o...
Source: Enzyme and Microbial Technology - September 30, 2017 Category: Biotechnology Source Type: research

Co-immobilization of enoate reductase with a cofactor-recycling partner enzyme
This study introduces simple and inexpensive co-immobilization strategies to construct novel and efficient ER-GDH-CLEAs and ER-GDH-SPs with high activity and stability. Graphical abstract (Source: Enzyme and Microbial Technology)
Source: Enzyme and Microbial Technology - September 30, 2017 Category: Biotechnology Source Type: research

Metabolic engineering of Escherichia coli for acetaldehyde overproduction using pyruvate decarboxylase from Zymomonas mobilis
Publication date: Available online 28 September 2017 Source:Enzyme and Microbial Technology Author(s): Balaji Balagurunathan, Lily Tan, Zhao Hua For the sustainable production of acetaldehyde, a key raw-material for a large number of chemical products, microbial production is a promising alternative. We have engineered an Escherichia coli strain for acetaldehyde production from glucose by introducing the pyruvate decarboxylase (Pdc) from Zymomonas mobilis and NADH oxidase (Nox) from Lactococcus lactis. Acetaldehyde production was systematically improved by knocking out the competing metabolic pathways. Multiple knockout s...
Source: Enzyme and Microbial Technology - September 29, 2017 Category: Biotechnology Source Type: research

Development of a bacterial propionate-biosensor for anaerobic digestion monitoring
Publication date: Available online 25 September 2017 Source:Enzyme and Microbial Technology Author(s): Joseph B. Sweeney, Cormac D. Murphy, Kevin McDonnell Monitoring anaerobic digestion (AD) leachate for changes in acetate and propionate concentrations is essential for effective AD operation. In this paper the development of a novel propionate cell-based biosensor is described. A previously designed E. coli mutant (IMD Wldgy) that could selectively determine acetate concentrations in synthetic leachates, based on oxygen uptake measurements, was used as a starting point in the development of a propionate biosensor. Howeve...
Source: Enzyme and Microbial Technology - September 27, 2017 Category: Biotechnology Source Type: research

Improved thermostability and enzyme activity of a recombinant phyA mutant phytase from Aspergillus niger N25 by directed evolution and 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-NPep-6A, a single transformant, T195L/Q368E/F376Y, was obtained with the significant improvements in catalytic efficiency and thermostability. The phytase gene of T195L/Q368E/F376Y, combined with the previous mutant phytase genes of PP-NPep-6A, PP-NPm-8 and I44E/T252R-PhyA, was then sequentially modified by DNA shuffling. Three genetically engineered strains with desirable properties were then obtained, namedQ172R, Q172R/K432R andQ368E/K432R....
Source: Enzyme and Microbial Technology - September 24, 2017 Category: Biotechnology Source Type: research

Baeyer-Villiger Monooxygenases from Yarrowia lipolytica Catalyze Preferentially Sulfoxidations
Publication date: Available online 20 September 2017 Source:Enzyme and Microbial Technology Author(s): Sven Bordewick, Andy Beier, Kathleen Balke, Uwe T. Bornscheuer Nine new putative Baeyer-Villiger monooxygenase encoding genes were identified in the eukaryote Yarrowia lipolytica and eight were subsequently cloned and expressed. Eight of these enzymes, Yarrowia monooxygenases A-H (YMOA-H), were used in biocatalysis reactions with ketones, sulfides and sulfoxides as substrates. YMOB converts ketones and sulfides, albeit with low activities. However, YMOA did not convert any of the tested ketone substrates, but showed acti...
Source: Enzyme and Microbial Technology - September 21, 2017 Category: Biotechnology Source Type: research

Spontaneous pepsin C-catalyzed activation of human pepsinogen C in transgenic rice cell suspension culture: Production and characterization of human pepsin C
Publication date: Available online 19 September 2017 Source:Enzyme and Microbial Technology Author(s): 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 ...
Source: Enzyme and Microbial Technology - September 20, 2017 Category: Biotechnology Source Type: research

Increased activity of β-glucuronidase variants produced by site-directed mutagenesis
Publication date: Available online 19 September 2017 Source:Enzyme and Microbial Technology Author(s): Xiaolei Zhang, Pongkwan Sitasuwan, Gary Horvath, Jia Yang, Yuzhe Nie, Margarita Marinova, L. Andrew Lee, Qian Wang β-glucuronidase (BGus) is an essential glycosyl hydrolase which has been widely used in biological and biomedical applications. In this paper, we report the construction and screening of nineteen Escherichia coli BGus (EBGus) mutants using site-directed mutagenesis. The mutants G559N, G559S and G559T showed a 3 to 5 fold increase in enzyme activity in comparison to wild type EBGus. In particular, G559S,...
Source: Enzyme and Microbial Technology - September 20, 2017 Category: Biotechnology Source Type: research

Deactivation and Activation of Lignocellulose Degrading Enzymes in the Presence of Laccase
Publication date: Available online 19 September 2017 Source:Enzyme and Microbial Technology Author(s): Rafaela I.S. Ladeira Ázar, Túlio Morgan, Antonio Carlos Freitas dos Santos, Eduardo de Aquino Ximenes, Michael R. Ladisch, Valéria M. Guimarães Cellulase and hemicellulase activities in a 1:1 ratio of enzymes extracted from Chrysoporthe cubensis and Penicillium pinophilum were evaluated in the presence of known monocomponent phenolic inhibitors and also with phenol mixtures derived from alkali pretreated sugarcane bagasse. The cellulolytic activities from C. cubensis:P. pinophilum displayed a ...
Source: Enzyme and Microbial Technology - September 20, 2017 Category: Biotechnology Source Type: research

Functional expression enhancement of Bacillus pumilus CotA-laccase mutant WLF through site-directed mutagenesis
Publication date: Available online 14 September 2017 Source:Enzyme and Microbial Technology Author(s): Quan Luo, Yu Chen, Jing Xia, Kai-Qiang Wang, Yu-Jie Cai, Xiang-Ru Liao, Zheng-Bing Guan Bacterial laccases are potential enzymes for biotechnological applications, such as detoxification of industrial effluents, decolorization of textile, and dimerization of phenolic acids, due to their remarkable advantages, including broad substrate spectrum, high thermostability, wide pH scope, and tolerance to alkaline environments. L386W/G417L/G57F (abbreviated as WLF), a good mutant of CotA-laccase from Bacillus pumilus W3, has bee...
Source: Enzyme and Microbial Technology - September 15, 2017 Category: Biotechnology Source Type: research

Enzymatic esterification of eugenol and benzoic acid by a novel chitosan-chitin nanowhiskers supported Rhizomucor miehei lipase: Process optimization and kinetic assessments
Publication date: Available online 12 September 2017 Source:Enzyme and Microbial Technology Author(s): 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 cat...
Source: Enzyme and Microbial Technology - September 13, 2017 Category: Biotechnology Source Type: research

Co-expression of an alcohol dehydrogenase and a cyclohexanone monooxygenase for cascade reactions facilitates the regeneration of the NADPH cofactor
Publication date: Available online 11 September 2017 Source:Enzyme and Microbial Technology Author(s): 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...
Source: Enzyme and Microbial Technology - September 12, 2017 Category: Biotechnology Source Type: research

A first glycoside hydrolase family 50 endo- β-1,3-D-glucanase from Pseudomonas aeruginosa
Publication date: Available online 4 September 2017 Source:Enzyme and Microbial Technology Author(s): 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 cu...
Source: Enzyme and Microbial Technology - September 5, 2017 Category: Biotechnology Source Type: research

Rational evolution of the unusual Y-type oxyanion hole of Rhodococcus sp CR53 lipase LipR
Publication date: Available online 4 September 2017 Source:Enzyme and Microbial Technology Author(s): 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 ...
Source: Enzyme and Microbial Technology - September 5, 2017 Category: Biotechnology Source Type: research

Displaying a recombinant protein on flocs self-produced by Escherichia coli through fused expression with elongation factor Ts
In this study, we demonstrated successful expression of a fusion protein consisting of Tsf and green fluorescence protein (GFP) on E. coli flocs. Interestingly, the percentage of Tsf-GFP in total floc protein reached approximately 15% (w/w). The proposed design of a fusion protein with Tsf enables displaying a recombinant target protein on the floc structure. (Source: Enzyme and Microbial Technology)
Source: Enzyme and Microbial Technology - September 3, 2017 Category: Biotechnology Source Type: research

Furfural and 5-Hydroxymethyl-Furfural Degradation using Recombinant Manganese Peroxidase
Publication date: Available online 31 August 2017 Source:Enzyme and Microbial Technology Author(s): 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 r...
Source: Enzyme and Microbial Technology - September 1, 2017 Category: Biotechnology Source Type: research

Encapsulation of lipase within metal-Organic framework (MOF) with enhanced activity intensified under ultrasound
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), zinc acetate (1.33mmol) along with sonicated lipase within 10min at room temperature (28±2°C). The prepared lipase-MOF was characterized by using FT-IR, FT-Raman, XRD, BET, confocal scanning laser microscopy, TGA and SEM. Further, the thermal...
Source: Enzyme and Microbial Technology - August 31, 2017 Category: Biotechnology Source Type: research

Exploring Trichoderma and Aspergillus secretomes: proteomics approaches for the identification of enzymes of biotechnological interest
Publication date: Available online 24 August 2017 Source:Enzyme and Microbial Technology Author(s): Nicholas de Mojana di Cologna, Diana Paola Gómez-Mendoza, Fabiana Fonseca Zanoelo, Giovana Cristina Giannesi, Nelciele Guimarães Cavalieri, Leonora Rios de Souza Moreira, Edivaldo Ximenes Ferreira-Filho, Carlos André Ornelas Ricart Filamentous fungal secretomes comprise highly dynamic sets of proteins, including multiple carbohydrate active enzymes (CAZymes) which are able to hydrolyze plant biomass polysaccharides into products of biotechnological interest such as fermentable sugars. In recent years, p...
Source: Enzyme and Microbial Technology - August 25, 2017 Category: Biotechnology Source Type: research

Investigating the Structural and Functional Features of Representative Recombinants of Chondroitinase ABC I
Publication date: Available online 24 August 2017 Source:Enzyme and Microbial Technology Author(s): 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 numb...
Source: Enzyme and Microbial Technology - August 25, 2017 Category: Biotechnology Source Type: research

In vitro biosynthesis of 3-mercaptolactate by lactate dehydrogenases
This study shows once more the impressive versatility of LDHs and presents a rapid and efficient biosynthesis process for 3ML, a biotechnologically interesting, yet hard-to-obtain, compound. (Source: Enzyme and Microbial Technology)
Source: Enzyme and Microbial Technology - August 25, 2017 Category: Biotechnology Source Type: research

A new pH indicator dye-based method for rapid and efficient screening of L-asparaginase producing microorganisms
Publication date: Available online 18 August 2017 Source:Enzyme and Microbial Technology Author(s): 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 1 BTB, bromothymol blue; dye-based plate assay. Screening of four different soil samples...
Source: Enzyme and Microbial Technology - August 18, 2017 Category: Biotechnology Source Type: research

Immobilization on graphene oxide improves the thermal stability and bioconversion efficiency of D-psicose 3-epimerase for rare sugar production
Publication date: Available online 10 August 2017 Source:Enzyme and Microbial Technology Author(s): 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 fro...
Source: Enzyme and Microbial Technology - August 10, 2017 Category: Biotechnology Source Type: research

Fluorescent CdSe QDs containing Bacillus licheniformis bioprobes for Copper (II) detection in water
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. The CdSe QD-containing Bacillus licheniformis cells were further used as whole fluorescent bio-probes to detect copper (II) (Cu2+) in water, which demonstrated a low limit of detection (0....
Source: Enzyme and Microbial Technology - August 8, 2017 Category: Biotechnology Source Type: research

Discovery, cloning and characterisation of proline specific prolyl endopeptidase, a gluten degrading thermo-stable enzyme from Sphaerobacter thermophiles
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. The molecular mass of the prolyl endopeptidase was estimated to be 77kDa by using SDS-PAGE. Enzyme activity assays with a synthetic dipeptide Z-Gly-Pro-p-nitroanilide as the substrate revealed that the enzyme had optimal activity at pH 6.6 and was most active from pH 5.0-8.0. The optimum temperature was 63 °C and residual activity after one hour incubation at 63 °C was higher than 75 %. The enzyme was activate...
Source: Enzyme and Microbial Technology - August 8, 2017 Category: Biotechnology Source Type: research

Enhanced production of xylitol from xylose by expression of Bacillus subtilis arabinose:H+ symporter and Scheffersomyces stipitis xylose reductase in recombinant Saccharomyces cerevisiae
Publication date: Available online 31 July 2017 Source:Enzyme and Microbial Technology Author(s): 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. T...
Source: Enzyme and Microbial Technology - August 1, 2017 Category: Biotechnology Source Type: research

Rational design of Kluyveromyces marxianus ZJB14056 aldo –keto reductase KmAKR to enhance diastereoselectivity and activity
Publication date: Available online 1 August 2017 Source:Enzyme and Microbial Technology Author(s): 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 (de p &...
Source: Enzyme and Microbial Technology - August 1, 2017 Category: Biotechnology Source Type: research

Enzymatic synthesis of chlorogenic acid glucoside using dextransucrase and its physical and functional properties
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. The production yield of CHG was 44.0% or 141mM, as determined by response surface methodology. CHG possessed a 65% increased water solubility and 2-fold browning resistance while it displayed stronger inhibition of lipid peroxidation and of colon cancer cell growth by MTT assay, compared to ch...
Source: Enzyme and Microbial Technology - July 29, 2017 Category: Biotechnology Source Type: research

Production of d-psicose from d-glucose by co-expression of d-psicose 3-epimerase and xylose isomerase
Publication date: October 2017 Source:Enzyme and Microbial Technology, Volume 105 Author(s): Xiaoyan Chen, Wen Wang, Jingliang Xu, Zhenhong Yuan, Tao Yuan, Yu Zhang, Cuiyi Liang, Minchao He, Ying Guo d-Psicose has been drawing increasing attention in recent years because of its medical and health applications. The production of d-psicose from d-glucose requires the co-expression and synergistic action of xylose isomerase and d-psicose 3-epimerase. To co-express these genes, vector pET-28a(+)-dual containing two T7 promoters and RBS sites and an Multiple Cloning Sites was constructed using the Escherichia coli expression p...
Source: Enzyme and Microbial Technology - July 28, 2017 Category: Biotechnology Source Type: research

Pathway engineering of Enterobacter aerogenes to improve acetoin production by reducing by-products formation
Publication date: Available online 25 July 2017 Source:Enzyme and Microbial Technology Author(s): Ji-Woong Jang, Hwi-Min Jung, Dae-Kyun Im, Moo-Young Jung, Min-Kyu Oh Enterobacter aerogenes was metabolically engineered for acetoin production. To remove the pathway enzymes that catalyzed the formation of by-products, the three genes encoding a lactate dehydrogenase (ldhA) and two 2,3-butanediol dehydrogenases (budC, and dhaD), respectively, were deleted from the genome. The acetoin production was higher under highly aerobic conditions. However, an extracellular glucose oxidative pathway in E. aerogenes was activated under ...
Source: Enzyme and Microbial Technology - July 26, 2017 Category: Biotechnology Source Type: research

Coupling xylitol dehydrogenase with NADH oxidase improves L-xylulose production in Escherichia coli culture
Publication date: Available online 24 July 2017 Source:Enzyme and Microbial Technology Author(s): Qi Han, Mark A. Eiteman Escherichia coli expressing NAD-dependent xylitol-4-dehydrogenase (XDH) from Pantoea ananatis and growing on glucose or glycerol converts xylitol to the rare sugar L-xylulose. Although blocking potential L-xylulose consumption (L-xylulosekinase, lyxK) or co-expression of the glycerol facilitator (glpF) did not significantly affect L-xylulose formation, co-expressing XDH with water-forming NADH oxidase (NOX) from Streptococcus pneumoniae increased L-xylulose formation in shake flasks when glycerol was t...
Source: Enzyme and Microbial Technology - July 25, 2017 Category: Biotechnology Source Type: research

Preparation, activity and structure of cross-linked enzyme aggregates (CLEAs) with nanoparticle
This study showed that it was potential to improve CLEAs performance by nano-TiO2 addition. Graphical abstract (Source: Enzyme and Microbial Technology)
Source: Enzyme and Microbial Technology - July 21, 2017 Category: Biotechnology Source Type: research

CAL-B-Catalyzed deacylation of benzylic acetates: Effect of amines addition. Comparison of several approaches
Publication date: Available online 18 July 2017 Source:Enzyme and Microbial Technology Author(s): 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 ...
Source: Enzyme and Microbial Technology - July 19, 2017 Category: Biotechnology Source Type: research

Improved stability of immobilized lipases via modification with polyethylenimine and glutaraldehyde
Publication date: November 2017 Source:Enzyme and Microbial Technology, Volume 106 Author(s): 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 glutaraldehy...
Source: Enzyme and Microbial Technology - July 19, 2017 Category: Biotechnology Source Type: research

Overexpressing key component genes of the secretion pathway for enhanced secretion of an Aspergillus niger glucose oxidase in Trichoderma reesei
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 (2.2-fold of the parental strain). hac1 and bip1, two more component genes in the secretion pathway, were further tested for overexpression and found to be also beneficial for AnGOD secretion. The overexpression of one component gene more or less affected the expression of the other two genes, suggesting a complex regulating mechanism. Our study demonstrates the potential of engineering the ...
Source: Enzyme and Microbial Technology - July 18, 2017 Category: Biotechnology Source Type: research

Direct rate assessment of laccase catalysed radical formation in lignin by electron paramagnetic resonance spectroscopy
Publication date: Available online 14 July 2017 Source:Enzyme and Microbial Technology Author(s): Line Munk, Mogens Larsen Andersen, Anne S. Meyer Laccases (EC 1.10.3.2) 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...
Source: Enzyme and Microbial Technology - July 15, 2017 Category: Biotechnology Source Type: research

Engineering Escherichia coli For Poly-(3-hydroxybutyrate) Production Guided by Genome-scale Metabolic Network Analysis
Publication date: Available online 10 July 2017 Source:Enzyme and Microbial Technology Author(s): 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...
Source: Enzyme and Microbial Technology - July 11, 2017 Category: Biotechnology Source Type: research

Impact of orientation of carbohydrate binding modules family 22 and 6 on the catalytic activity of Thermotoga maritima xylanase XynB
This study shows that the active site residues of the catalytic domain and the binding residues of the CBM are arranged in a unique fashion, not reported before. (Source: Enzyme and Microbial Technology)
Source: Enzyme and Microbial Technology - July 11, 2017 Category: Biotechnology Source Type: research

Selenium nanoparticle-enriched biomass of Yarrowia lipolytica enhances growth and survival of Artemia salina
Publication date: Available online 8 July 2017 Source:Enzyme and Microbial Technology Author(s): 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 synth...
Source: Enzyme and Microbial Technology - July 9, 2017 Category: Biotechnology Source Type: research

Fungal BVMOs as alternatives to cyclohexanone monooxygenase
Publication date: November 2017 Source:Enzyme and Microbial Technology, Volume 106 Author(s): Katlego Siphamandla Mthethwa, Karin Kassier, Jennifer Engel, Selin Kara, Martha Sophia Smit, Diederik Johannes Opperman FAD-dependent Baeyer-Villiger monooxygenases (BVMOs) have proven to be useful biocatalysts in the selective and specific oxygenation of various ketones. Despite the cloning, heterologous expression and characterization of close to 80 members of this enzyme family, some sub-groups of BVMOs still remain underrepresented and their evolutionary relationship uncertain. Until recently, very few fungal BVMOs have been ...
Source: Enzyme and Microbial Technology - July 8, 2017 Category: Biotechnology Source Type: research

Improved stability of immobilized lipases via modification with polyethylenimine and glutaraldehyde.
Publication date: Available online 6 July 2017 Source:Enzyme and Microbial Technology Author(s): 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 glutarald...
Source: Enzyme and Microbial Technology - July 7, 2017 Category: Biotechnology Source Type: research

Fungal BVMOs as alternatives to cyclohexanone monoxygenase
Publication date: Available online 3 July 2017 Source:Enzyme and Microbial Technology Author(s): Katlego Siphamandla Mthethwa, Karin Kassier, Jennifer Engel, Selin Kara, Martha Sophia Smit, Diederik Johannes Opperman FAD-dependent Baeyer-Villiger monooxygenases (BVMOs) have proven to be useful biocatalysts in the selective and specific oxygenation of various ketones. Despite the cloning, heterologous expression and characterization of close to 80 members of this enzyme family, some sub-groups of BVMOs still remain underrepresented and their evolutionary relationship uncertain. Until recently, very few fungal BVMOs have be...
Source: Enzyme and Microbial Technology - July 4, 2017 Category: Biotechnology Source Type: research

Improvement of enzyme activity and soluble expression of an alkaline protease isolated from oil-polluted mud flat metagenome by random mutagenesis
Publication date: Available online 28 June 2017 Source:Enzyme and Microbial Technology Author(s): 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) ...
Source: Enzyme and Microbial Technology - June 29, 2017 Category: Biotechnology Source Type: research

Enzyme-based processing of soybean carbohydrate: recent developments and future prospects
Publication date: Available online 28 June 2017 Source:Enzyme and Microbial Technology Author(s): 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 hydrolysable 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 ...
Source: Enzyme and Microbial Technology - June 29, 2017 Category: Biotechnology Source Type: research

Construction and functional analysis of a whole-cell biocatalyst based on CYP108N7
Publication date: Available online 29 June 2017 Source:Enzyme and Microbial Technology Author(s): 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...
Source: Enzyme and Microbial Technology - June 29, 2017 Category: Biotechnology Source Type: research

Global substitution of hemeproteins with noncanonical amino acids in Escherichia coli with intact cofactor maturation machinery
Publication date: Available online 29 June 2017 Source:Enzyme and Microbial Technology Author(s): 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 hemeprotein...
Source: Enzyme and Microbial Technology - June 29, 2017 Category: Biotechnology Source Type: research

CO2-H2O based pretreatment and enzyme hydrolysis of soybean hulls
Publication date: Available online 27 June 2017 Source:Enzyme and Microbial Technology Author(s): S.M. Mahfuzul Islam, Qian Li, Abdullah Al Loman, Lu-Kwang Ju The high carbohydrate content of soybean hull makes it an attractive biorefinery resource. But hydrolyzing its complex structure requires concerted enzyme activities, at least cellulase, xylanase, pectinase and α-galactosidase. Effective pretreatment that generates minimal inhibitory products is important to facilitate enzymatic hydrolysis. Combined CO2-H2O pretreatment and enzymatic hydrolysis by Aspergillus niger and Trichoderma reesei enzyme broths was stud...
Source: Enzyme and Microbial Technology - June 28, 2017 Category: Biotechnology Source Type: research