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Enzyme and Microbial Technology

Debajyoti Bose, Himanshi Dhawan, Vaibhaw Kandpal, Parthasarthy Vijay, Margavelu Gopinath
Wastewater from sewage sources contribute significantly to water pollution from domestic waste; one way to recover energy from these sources while at the same time, treating the water is possible using Microbial Fuel Cell. In this work, a two chambered microbial fuel cell was designed and fabricated with carbon cloth electrodes and Nafion-117 membrane, having Platinum as the catalyst. Wastewater from an organic load of 820 ± 30 mg/l reduced to around 170 mg/l, with the change in pH from 7.65 ± 0...
November 2018: Enzyme and Microbial Technology
Pallvi Sehajpal, Seema Kirar, Saptarshi Ghosh, Uttam Chand Banerjee
Biocatalysis has shown tremendous potential in the synthesis of drugs and drug intermediates in the last decade. Screening of novel biocatalysts from the natural genome space is the growing trend to replenish the harsh chemical synthetic routes, commonly used in the pharmaceutical and chemical industry. Here, we report a novel ketoreductase (KERD) and a nitrile reductase isolated from the PCR based library generated from the genome of Rhodococcus ruber and Bacillus subtilis, respectively. Both the proteins are hypothetical in nature as there is no putative homology found in the database, although both the enzymes have significant activity towards the synthesis of chiral alcohols and amines...
November 2018: Enzyme and Microbial Technology
Tae-Su Kim, Tuoi Thi Le, Hue Thi Nguyen, Kye Woon Cho, Jae Kyung Sohng
Glycosyltransferases (GTs) are key enzymes for the post-modification of secondary metabolites in drug development processes. In our prior research, an one-pot enzymatic system produced α-mangostin 3,6-di-O-β-D-glucopyranoside (Mg1) at a higher proportion using wild-type glycosyltransferase (YjiC) but α-mangostin 3-O-β-D-glucopyranoside (Mg2) exhibited markedly higher anti-bacterial activities. This study focuses on a Bacillus licheniformis-originated flexible glycosyltransferase by mutagenesis to examine the active site residues involved in glycosylation for a product specificity towards Mg2...
November 2018: Enzyme and Microbial Technology
Ayumi Shikata, Junjarus Sermsathanaswadi, Phakhinee Thianheng, Sirilak Baramee, Chakrit Tachaapaikoon, Rattiya Waeonukul, Patthra Pason, Khanok Ratanakhanokchai, Akihiko Kosugi
The generation of a complex microbial consortium is a promising approach for efficient biomass decomposition. An anaerobic thermophilic alkaliphilic microbial consortium with efficient degradation ability was screened from bovine manure compost using non-pretreated milling corn stover (CS) and rice straw (RS). A stable microbial consortium ISHI-3 with high degradation ability for CS and RS was isolated by the roll tube technique. ISHI-3 comprised Herbivorax saccincola and bacteria belonging to the classes Pelotomaculum, Tepidanaerobacter, and Tepidimicrobium, as determined by DGGE of the PCR-generated 16S rRNA genes...
November 2018: Enzyme and Microbial Technology
Yanran Xu, Lei Zhang, Buyong Ma, Lifu Hu, Huili Lu, Tonglu Dou, Junsheng Chen, Jianwei Zhu
Npu DnaE is a naturally occurred split intein possessing robust trans-splicing activity and could be engineered to perform rapid C-terminal cleavage module by a single mutation D118G. Unfortunately, however, for this modified selfcleaving module, reducing agents were needed to trigger the rapid cleavage, which prevents the utilization in purification of disulfide bonds containing recombinant proteins. In this study, we demonstrated that the unpaired cysteine residues in Npu DnaE tend to form disulfide bonds, and contributed to the reduction of the cleavage under non-reducing conditions...
November 2018: Enzyme and Microbial Technology
Yun-Gi Hong, Yu-Mi Moon, Ju-Won Hong, So-Young No, Tae-Rim Choi, Hye-Rim Jung, Soo-Yeon Yang, Shashi Kant Bhatia, Jung-Oh Ahn, Kyung-Moon Park, Yung-Hun Yang
Glutaric acid is one of the promising C5 platform compounds in the biochemical industry. It can be produced chemically, through the ring-opening of butyrolactone followed by hydrolysis. Alternatively, glutaric acid can be produced via lysine degradation pathways by microorganisms. In microorganisms, the overexpression of enzymes involved in this pathway from E. coli and C. glutamicum has resulted in high accumulation of 5-aminovaleric acid. However, the conversion from 5-aminovaleric acid to glutaric acid has resulted in a relatively low conversion yield for unknown reasons...
November 2018: Enzyme and Microbial Technology
Xiang-Chao Wang, Sheng-Ping You, Jia-Xing Zhang, Ye-Mei Dai, Cheng-Yu Zhang, Wei Qi, Tong-Yi Dou, Rong-Xin Su, Zhi-Min He
A rational design method to improve β-mannanase (ManTJ102) thermostability was developed successfully in this study. The flexible area of residues 330-340 in ManTJ102 was firstly selected from analysis of molecular dynamics simulation and then the critical amino acid residue (Ala336Pro) with the lowest mutation energy was determined by virtual mutation, whose mutant was named as Mutant336. Afterward, the dynamics transition temperature (Tdtt ) of ManTJ102 and Mutant336 was evaluated by simulated annealing and heating, and Mutant336 with higher Tdtt was implemented for experimental verification of the enzyme thermostability...
November 2018: Enzyme and Microbial Technology
Lavika Jain, Akhilesh Kumar Kurmi, Deepti Agrawal
The process economics of fermentable sugar production is dependent on the performance of cellulase cocktail on realistic lignocellulosic biomass and their capability to be recovered and recycled. Feasibility studies were conducted to enhance the digestibility of acid pretreated sugarcane bagasse using novel cellulase cocktail obtained from stable mutant UV-8 of Talaromyces verruculosus IIPC 324 in presence of lignin blocking additives. PEG 6000 was shortlisted as the best additive as it could simultaneously enhance saccharification and overall cellulase recoveries namely cellobiohydrolase, endoglucanase and cellobiase...
November 2018: Enzyme and Microbial Technology
Saiwei Zhang, Ya-Nan Wang, Lei Wang, Yiu Fai Tsang, Huan Li, Xiaohua Fu
Alcaligenes hydrogenophilus was used to verify the role of the electron donor and acceptor in apparent CO2 fixation of chemoautotrophic bacteria. The response mechanisms underlying the apparent CO2 fixation characteristics with different concentrations of electron donor and acceptor were elucidated by analyzing the transcription characteristics of the cbbL gene, cytoskeleton synthesis efficiency and extracellular free organic carbon concentration. The results showed that the apparent CO2 fixation efficiency of A...
November 2018: Enzyme and Microbial Technology
Soo-Jung Moon, Han-Woo Kim, Sung-Jong Jeon
A putative laccase-like gene, GPPO, encoding a protein of 17.2 kDa and belonging to the multicopper oxidase family, was cloned and overexpressed in Escherichia coli cells. The purified recombinant protein GPPO is homodecameric protein with a molecular weight of 171.6 kDa. GPPO was not detected the ultraviolet-visible spectroscopy (UV/Vis) spectrum of typical laccases. Co2+ or Cu2+ was essential for substrate oxidation of GPPO, and the enzyme contained 1 mol of Co or Cu per mole of protein. The optimum pH required for the oxidation of 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonate) (ABTS) and 2,6-dimethoxyphenol (DMP) was 4...
November 2018: Enzyme and Microbial Technology
Katsuhiro Yoshii, Masako Ogasawara, Yoshihiro Yamamoto, Kuniyo Inouye
A fraction (designated as U3EE) with molecular mass under 3 kDa from the water extract of the earthworm Eisenia fetida was prepared and its effects on mammalian digestive enzymes were examined. U3EE itself showed no relevant enzyme activities. However, it increased the activities of trypsin, α-chymotrypsin, and lipase, while decreased those of α-amylase and α-glucosidase. The trypsin activation and α-amylase inhibition were analyzed precisely by enzyme kinetics. The former was solely dependent on increase in the molecular activity kcat without any change in the Michaelis constant Km , and the latter was mainly dependent on decrease in Km with a slight change in kcat ...
November 2018: Enzyme and Microbial Technology
Debbie Soefie Retnoningrum, Sekar Arumsari, Eva Selenia Desi, Yanuar Sebastian Tandra, Anita Artarini, Wangsa Tirta Ismaya
Manganese superoxide dismutase from Staphylococcus equorum (MnSODSeq) maintains its activity after up to 45 minutes of UVC radiation. The enzyme occurs in a dimeric form that likely contributes to its activity and stability. Therefore, maintaining the dimeric form could be a way to improve the enzyme's stability. One of the main interactions for dimer formation occurs between Tyr168 and His31, of which the latter is also involved in the enzymatic reaction. UVC radiation may cause alterations in the electronic structure of the phenolic ring in the Tyr168 side chain: this may disrupt the Tyr168-His31 pairing and lead to enzyme instability and/or activity loss...
November 2018: Enzyme and Microbial Technology
Carla Aburto, Cecilia Guerrero, Carlos Vera, Lorena Wilson, Andrés Illanes
Simultaneous synthesis and purification (SSP) of galacto-oligosaccharides (GOS) from lactose was conducted using a combi-biocatalyst formed by crosslinked enzyme aggregates of Aspergillus oryzae β-galactosidase and Saccharomyces cerevisiae cells co-immobilized by entrapment in calcium alginate gel particles. Product yield obtained with the combi-biocatalyst was similar than obtained with the soluble enzyme (23.3%), having a final purity of 25.7%. During the simultaneous process, ethyl-β-galactoside was produced from the ethanol generated as a metabolic product of yeast cells, but ethyl-β-galactoside was considerably decreased at high aeration (4 vvm)...
November 2018: Enzyme and Microbial Technology
Annika Meyers, Christoph Furtmann, Joachim Jose
A convenient and most abundantly applied method to determine the growth state of a bacterial cell culture is to determine the optical density (OD) spectrophotometrically. Dilution of the samples, which is necessary to measure within the linear range of the spectrophotometer, is time-consuming and not compatible with high-throughput applications. Here we present a direct approach to estimate the OD at 578 nm (OD578 ) of bacterial cultures in microplates without the need for sample dilution. This could be advantageous for high-throughput analysis of bacterial cells in microplates for example when optimizing growth conditions, screening for new substrates of a bacterial strain or monitoring enzymatic activity after enzyme evolution...
November 2018: Enzyme and Microbial Technology
Song Li, Qian Yang, Bin Tang, Ana Chen
Optimal pH and ideal functioning temperature for fungal α-amylase can greatly contribute to improving enzyme efficiency in maltose-forming ability. This work aimed to improve the enzymatic properties of Rhizopus oryzae α-amylase by site-saturation mutagenesis of histidine 286. The biochemical properties of selected mutant enzymes were modified to increase their enzymatic efficiencies compared to their wild-type counterparts. For instance, the optimum temperature of mutants H286 L, H286I, H286S and H286 T was increased from 50 °C to 55 °C, while a similar increase was observed for H286 P from 50 °C to 60 °C...
October 2018: Enzyme and Microbial Technology
S Rajeshkumar, S Venkat Kumar, Arunachalam Ramaiah, Happy Agarwal, T Lakshmi, Selvaraj Mohana Roopan
Green synthesis is an eco-friendly approach to nanoparticle production, which eliminates the use of toxic chemicals, high temperatures, and costly equipment needed for traditional physical and chemical synthesis methods. This eco-friendly approach was used in the present study to biosynthesize zinc oxide nanoparticles (ZnO NPs) from Mangifera indica (mango) leaves which were then evaluated for their antioxidant activity and cytotoxic effects on lung cancer A549 cells. Synthesized ZnO nanoparticles were characterized using UV-vis spectroscopy, XRD, SEM, and EDX analyses...
October 2018: Enzyme and Microbial Technology
Zhengfei Yang, Xiaolin Pei, Gang Xu, Jianping Wu, Lirong Yang
Nitrile hydratase which catalyzes the hydration of nitriles to the corresponding amides is operon-encoded. However, when heterologously expressed, genes in the same operon are usually not equally expressed, and the ratio needs to be fine-tuned. A gene cluster of three genes (corresponding to α-subunit, β-subunit and activator) encoding the nitrile hydratase was cloned from Aurantimonas manganoxydans ATCC BAA-1229 and expressed in Escherichia coli. However, difficulty was encountered in heterologous expression of the activator and the expression level of β-subunit was lower than that of α-subunit, which together resulted in low catalytic efficiency...
October 2018: Enzyme and Microbial Technology
Won Je Jang, Jong Min Lee, Hae Dae Park, Yu Bin Choi, In-Soo Kong
Pseudomonas sp. FB15 producing phytase with a high activity at low temperature was isolated from foreshore soil. The phytase gene was cloned and sequenced. Molecular modeling predictions using its amino acid sequence indicated that it belongs to the group of beta-propeller phytases (BPPs). However, it differs from the conventional structure of BPPs in the number of propeller-shaped domains. Most BPPs have a propeller with six blades that consist of four or five beta-sheets. However, the BPP from the isolated strain contained a C-terminal domain containing a conserved BPP sequence and also an N-terminal domain consisting of an additional 275 amino acids...
October 2018: Enzyme and Microbial Technology
Xinping Zeng, Mengtian Zhang, Yunying Liu, Wenwei Tang
Manganese contamination of groundwater exists worldwide. Manganese removal is primarily performed through catalytic oxidation by manganese-oxidizing bacteria. In this study, we identified a new manganese(II) oxidase (CopA) from Brevibacillus panacihumi MK-8. The copA gene was cloned and expressed in Escherichia coli strain BL21(DE3), and the recombinant strain BL21-pET-copA was able to remove 85.87% of Mn(II) from LB medium containing 1 mM Mn(II) after seven days. The optimum Mn(II) oxidase CopA activity was obtained at 37 °C in 10 mM HEPES buffer (pH 8...
October 2018: Enzyme and Microbial Technology
Zhuotong Zeng, Bi Tang, Rong Xiao, Jinhui Huang, Yanling Gu, Yahui Shi, Yi Hu, Jianxin Zhou, Hua Li, Lixiu Shi, Guangming Zeng
In order to improve the antifouling properties of quorum quenching (QQ) bacteria immobilized beads, the mechanical strength and permeability of QQ beads were modified by adding powdered activated carbon (PAC) based on traditional polyvinyl alcohol (PVA)-boric acid method. Optimal PAC concentration was investigated through measuring the mechanical strength, permeability and N-octanoyl-DLhomoserine lactone (C8-HSL) removal ratio of the PAC-PVA beads. Particularly, the enhanced antifouling effects of the optimal PAC-PVA beads were compared with those of original QQ beads through a membrane filtration experiment under constant pressure...
October 2018: Enzyme and Microbial Technology
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