检索结果-南通市图书馆

同方期刊数据库

Preliminary Study towards Enhanced Crude Oil Biodegradation Reveals Congeneric Total Peroxidases with Striking Distinctions

在线全文

学校读者我要写书评

暂无评论

Advances in enzyme Research 2015年第3期3卷 66-74页

作者： Folasade M. Olajuyigbe Kevin I. Ehiosun Kikelomo F. Jaiyesimi enzyme biotechnology unit Department of Biochemistry Federal University of Technology Akure Nigeria

Peroxidases (POXs) are the key extracellular enzymes produced by crude oil degrading microbes. Knowledge of optimum conditions for POXs activity is crucial for providing effective environment for bioremediation. In this study, physicochemical properties of POXs produced by Actinomyces israelii and Actinomyces viscosus during growth on crude oil were studied. The POXs exhibited similarities in activity and stability with striking differences in response to two divalent metal ions. The POXs from both species had optimum pH of 7.0 and were very stable over a narrow pH range (6.0 - 8.0). The POXs demonstrated similar thermostability exhibiting relative residual activity of 62% at 50°C after 30 min incubation and 45% residual activity at the same temperature after 60 min despite the fact that POXs from A. viscosus and A. israelii had optimum temperatures of 50°C and 40°C, respectively. The POXs from A. viscosus and A. israelii were greatly activated by Fe2+ at 5.0 and 10.0 mM. The enzymes were both strongly inhibited by Cu2+, Mg2+ and Hg2+. Surprisingly, these congeneric POXs demonstrated striking differences in their response to Ca2+ and Mn2+. POX from A. viscosus was activated by Ca2+ and Mn2+ exhibiting relative activity of 136% and 106% at 5 mM, respectively. In contrast, POX from A. israelii was strongly inhibited by Ca2+ and Mn2+ exhibiting 62.5% relative activity in the presence of 5 mM of each metal ion. Increasing the concentration of Ca2+ and Mn2+ led to further activation of POX from A. viscosus and inhibition of POX from A. israelii. Results provide deeper insights into functional properties of studied POXs from closely related microbes. The physicochemical properties are very similar;however, notable differences provide a strong basis for structural characterization of these congeneric enzymes.

关键词： Actinomyces israelii Actinomyces viscosus Bioremediation Congeneric enzymes Crude Oil Peroxidases

Lime pretreatment of maize stover and solubilization of pretreated solids by enzymatic hydrolysis and Clostridium thermocellum fermentation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2024年第4期17卷 288-296页

作者： Guanying Wang Gang Zhang Xiongjun Shao State Key Laboratory of Biocatalysis and enzyme Engineering/Hubei Key Laboratory of Industrial biotechnology School of Life SciencesHubei UniversityWuhan 430062China

Lime pretreatment on maize stover was conducted with various pretreatment conditions selected by central composite *** and lignin contents in pretreated maize stover were relatively *** of glucose monomer and oligomers decreased while concentration of xylooligomers increased in the pretreatment hydrolysate with increasing pretreatment *** overall carbohydrate recovery was at least 85%for the conditions *** removal during pretreatment was found to have a linear correlation with lignin *** had a higher effect in enhancing carbohydrate solubilization for enzymatic hydrolysis than that for *** *** all the pretreated solids,Clostridium thermocellum fermentation was found to result in much higher carbohydrate solubilization than enzymatic hydrolysis with a cellulase loading of 8 mg/g solids and a xylanase loading of 2 mg/g *** solubilization was found to have a linear correlation with lignin removal during lime pretreatment for both enzymatic hydrolysis and *** *** the current challenges,this research provides a new idea for the industrial application of lignocellulosic biorefinery.

关键词： central composite design lime pretreatment enzymatic hydrolysis clostridium thermocellum carbohydrate solubilization

Enhanced Production of Salinity-Induced Proteases from Aspergillus flavusand Aspergillus niger

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in enzyme Research 2019年第4期7卷 45-56页

作者： Michael O. Okpara Olufemi S. Bamidele Joshua O. Ajele Enzymology and enzyme biotechnology unit Department of Biochemistry Federal University of Technology Akure Nigeria

Proteases are important industrial enzymes that account for about 60% of the total enzyme market globally due to their large application in food, feed, textile and pharmaceutical industries. The effect of salt stress on protease production was evaluated on Aspergillus flavus and Aspergillus niger. The enzyme production was enhanced by stepwise optimization of the culture parameters, notably, carbon source, nitrogen source, pH, and temperature of the submerged fermentation process while using a minimal salt media and casein as substrate for the protease activity. The fungi species were found to be good producers of both acid and alkaline proteases under 4% salt stress condition. The optimum culture conditions for alkaline protease production by Aspergillus flavus were sucrose 4%, peptone 1%, pH 8 at 40°C with maximum enzymatic activities of 8.85 mM/min/mg protein, 5.22 mM/min/mg protein, 3.75 mM/min/mg protein, and 1.64 mM/min/mg protein, respectively. Lactose 4%, peptone 1%, pH 6 at 50°C were the optimum culture conditions for acid protease production by Aspergillus flavus with maximum enzymatic activities of 4.59 mM/min/mg protein, 2.06 mM/min/mg protein, 1.24 mM/min/mg protein, and 1.23 mM/min/mg protein, respectively. For Aspergillus niger, the optimum culture conditions for alkaline protease production were corn starch 4%, yeast extract 1%, pH 6 at 40°C with maximum enzymatic activities of 5.99 mM/min/mg protein, 3.85 mM/min/mg protein, 6.18 mM/min/mg protein, and 3.72 mM/min/mg protein, respectively. While lactose 4%, yeast extract 1%, pH 6 at 50°C were the best culture conditions for acid protease production by Aspergillus niger with maximum enzymatic activities of 4.81 mM/min/mg protein, 0.93 mM/min/mg protein, 5.71 mM/min/mg protein, and 3.34 mM/min/mg protein, respectively.

关键词： Protease Salt-Stress Fermentation enzymes Optimization

Mechanism and Application of enzyme Treatment on Wool

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Donghua University(English Edition) 2011年第2期28卷 226-232页

作者：程文红周启澄袁琴华 State Key Laboratory of Non-food Biomass and enzyme Technology Guangxi Academy of Sciences College of Textiles Donghua University College of Chemistry Chemical Engineering and Biotechnology Donghua University

Protease treatments on wool have its inherent defect in shrink-proofing because protease will decompose wool through cell membrane complex （CMC）. In order to solve this problem, mechanism of enzyme treatments on wool was adequately analyzed and possible enzyme applications were discussed. The mechanism of enzyme treatment on wool was analyzed through weight loss, strength, scanning electron microscopy （SEM）, electrophoresis, sodium dodecyl sulfate polyacrylamide gel electrophoresis （ SDS- PAGE）, and amino acids composition. Based on the results, a possible novel multifunetional enzyme treatment on wool to achieve shrink-resistance was proposed. In order to shorten enzyme treatment time, the rate of proteolysis of wool was investigated. Considering the specificity of proteases, wool composition, and structure of dyes, a better enzyme pretreatment before dyeing to get better dyeabflity and lower dyeing temperature was discussed.

关键词： enzyme treatments wool mechanism and application dyeability

Visualizing the Transport of Porcine Reproductive and Respiratory Syndrome Virus in Live Cells by Quantum Dots-Based Single Virus Tracking

在线全文

学校读者我要写书评

暂无评论

Virologica Sinica 2020年第4期35卷 407-416页

作者： Zhenpu Liang Pengjuan Li Caiping Wang Deepali Singh Xiaoxia Zhang College of Life Sciences Key Laboratory of Enzyme Engineering of Agricultural Microbiology(Ministry of Agriculture)Henan Agricultural UniversityZhengzhou 450000China School of biotechnology Gautam Buddha UniversityGreater Noida 201312India

Quantum dots(QDs)-based single particle analysis technique enables real-time tracking of the viral infection in live cells with great sensitivity over a long period of *** porcine reproductive and respiratory syndrome virus(PRRSV)is a small virus with the virion size of 40–60 nm which causes great economic losses to the swine industry worldwide.A clear understanding of the viral infection mechanism is essential for the development of effective antiviral *** this study,we labeled the PRRSV with QDs using the streptavidin–biotin labeling system and monitored the viral infection process in live *** results indicated that the labeling method had negligible effect on viral *** also observed that prior to the entry,PRRSV vibrated on the plasma membrane,and entered the cells via endosome mediated cell entry *** moved in a slow–fast–slow oscillatory movement pattern and finally accumulated in a perinuclear region of the *** results also showed that once inside the cell,PRRSV moved along the microtubule,microfilament and vimentin cytoskeletal *** the transport process,virus particles also made contacts with non-muscle myosin heavy chainⅡ-A(NMHCⅡ-A),visualized as small spheres in *** study can facilitate the application of QDs in virus infection imaging,especially the smaller-sized viruses and provide some novel and important insights into PRRSV infection mechanism.

关键词： Single virus tracking Quantum dots(QDs) Biotinylation Porcine reproductive and respiratory syndrome virus(PRRSV) Transport

Cloning and characterization of a thermostable carboxylesterase from inshore hot spring thermophile Geobacillus ***1

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2012年第6期31卷 117-126页

作者： ZHU Yanbing LIU Guangming LI Hebin LIU Jingwen BAI Xiaoming CAI Huinong School of biotechnology Engineering Jimei UniversityXiamen 361021China Research Center of Food Microbiology and enzyme Engineering Technology(Jimei University)Pujian Province University Xiamen 361021China Research Center of Food biotechnology of Xiamen City Xiamen 361021China Xiamen Medical College Xiamen 361008China

The gene （741 bp） encoding carboxylesterase from the thermophilic bacterium Geobacillus sp. ZH1 was cloned and overexpressed in Escherichia coll. The purified recombinant protein presented a molecular mass of about 40 kDa by SDS-PAGE analysis. enzyme assays using p-nitrophenyl esters with different acyl chain lengths as the substrates confirmed its esterase activity, yielding highest specific activity with p-nitrophenyl acetate. Among the p-nitrophenyl esters tested, the carboxylesterase presented preference for p-nitrophenyl caprylate, but hydrolyzed p-nitrophenyl butyrate more efficiently. When p-nitrophenyl butyrate was used as a substrate, the recombinant carboxylesterase exhibited highest activity at pH 8.0 and 60℃. Almost no decrease in esterase activity was observed at 60℃ for 3 h, and over 40% of activity was still maintained after incubation at 90℃ for 3 h. These results indicate that Geobacillus sp. ZH1 recombinant esterase was thermostable. The enzymatic activity was inhibited by the addition of phenylmethylsulfonyl fluoride, indicating that it contains serine residue, which plays a key role in the catalytic mechanism. Except SDS and xylene, this esterase showed stability toward other tested detergents and organic solvents. Cloning, expression, and biochemical characterization of Geobacillus sp. ZH1 carboxylesterase lay a good foundation for its structural characterization and industrial application.

关键词： carboxylesterase expression characterization

Highly Sensitive and Specific Monoclonal Antibody-Based Serological Methods for Rice Ragged Stunt Virus Detection in Rice Plants and Rice Brown Planthopper Vectors

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2014年第9期13卷 1943-1951页

作者： LIU Huan SONG Xi-jiao NI Yue-qun LU Li-na ZHOU Xue-ping WU Jian-xiang Institute of biotechnology College of Agriculture & Biotechnology Zhejiang University

Rice ragged stunt virus（RRSV） is a serious rice disease in Asia, causing serious yield losses on rice. The capsid protein（CP） gene of the major outer capsid protein of RRSV was expressed in Escherichia coli BL21（DE3） using the pMAL-C2 X expression vector. The recombinant protein was used as the immunogen to immunize BALB/c mice. A hybridoma cell line 8A12 secreting monoclonal antibody（MAb） against RRSV was obtained by fusing mouse myeloma cells（Sp 2/0） with spleen cells from the immunized BALB/c mice. Western blot analysis showed that the MAb 8A12 can specifically react with RRSV CP. Using the MAb, an antigen-coated-plate enzyme-linked immunosorbent assay（ACP-ELISA）, a dot enzyme-linked immunosorbent assay（dot-ELISA）, and immunocapture-RT-PCR（IC-RT-PCR） assay were developed to detect RRSV. The established ACP-ELISA, dot-blot ELISA and IC-RT-PCR methods could detect RRSV in infected rice tissue crude extracts with dilutions of 1：40 960, 1：1 280 and 1：655 360（w/v, g mL-1）, respectively. The ACP-ELISA and dot-blot ELISA methods could detect RRSV in infected insect vector crude extracts with dilutions of 1：12 800 and 1：1 600（an individual planthopper μL-1）, respectively. The field survey revealed that Rice ragged stunt disease occurs on rice in Hainan, Yunnan, Guangxi, Sichuan, Guizhou, Fujian, Hunan, Jiangxi and Zhejiang in China.

关键词： Rice ragged stunt virus rice brown planthopper monoclonal antibody antigen-coated-plate enzyme-linked immunosorbent assay(ACP-ELISA) dot-blot ELISA immunocapture RT-PCR

Optimization of Parameters for the Production of Lipase from Pseudomonas sp. BUP6 by Solid State Fermentation

在线全文

学校读者我要写书评

暂无评论

Advances in enzyme Research 2014年第4期2卷 125-133页

作者： Panichikkal Abdul Faisal Erandapurthukadumana Sreedharan Hareesh Prakasan Priji Kizhakkepowathial Nair Unni Sreedharan Sajith Sasidharan Sreedevi Moolakkariyil Sarath Josh Sailas Benjamin enzyme Technology Laboratory Biotechnology Division Department of Botany University of Calicut Kerala India

Solid-state fermentation (SSF) holds tremendous potentials for the production of industrially significant enzymes. The present study describes the production of lipase by a novel rumen bacterium, Pseudomonas sp. strain BUP6 on agro-industrial residues. Pseudomonas sp. strain BUP6 showed higher lipase production when grown in Basal salt medium (BSM) supplemented with oil cakes. Initially, five different oil cakes (obtained after extracting oil from coconut, groundnut, cotton seed, gingelly or soybean) were screened to find out the most suitable substrate-cum-inducer for the production of lipase. Among them, groundnut cake supported the maximum production of lipase (107.44 U/gds). Box-Behnken Design (BBD), followed by response surface methodology (RSM) was employed to optimize the culture parameters for maximizing the production of lipase. Using the software Minitab 14, four different parameters like temperature, pH, moisture content and incubation time were selected for the statistical optimization, which resulted in 0.7 fold increase (i.e., 180.75 U/gds) in production of lipase under the optimum culture conditions (temperature 28°C, pH 5.9, moisture 33% and incubation 2 d). Thus, this study signifies the importance of SSF for the production of industrially-significant lipase using agro-industrial residues as solid support.

关键词： Lipase Solid-State Fermentation Basal Salt Medium Oil Cakes Response Surface Methodology

A novel strain of Trichoderma virideshows complete lignocellulolytic activities

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Bioscience and biotechnology 2012年第8期3卷 1160-1166页

作者： Kannan Neethu M. Rubeena S. Sajith S. Sreedevi Prakasan Priji K. N. Unni M. K. Sarath Josh V. N. Jisha S. Pradeep Sailas Benjamin enzyme Technology Laboratory Biotechnology Division Department of Botany University of Calicut Malappuram India

In this study we describe a novel dark-green strain of Trichoderma viride exhibiting complete ensemble of cellulase, hemicellulase and ligninase activities on specific plate assays. To assess the cellulase production in detail, basal salt medium (BSM) was fortified with synthetic (carboxymethyl cellulose (CMC), glucose, sucrose, dextrose, lactose or maltose) and natural (flours of banana, banana peel, jack seed, potato or tapioca) carbon as well as nitrogen (yeast extract, beef extract, peptone, NaNO3 or NH4NO3) sources. Temperature and pH optima were 28°C and 4, respectively for the growth of the fungus in CMC-BSM with 137 U/mL cellulase activity, which was enhanced to 173 U/mL at 1.25% CMC concentration. Flours of potato and banana peel supported comparable yields of cellulase to that of CMC, while sodium nitrate was the preferred nitrogen source. The water soluble bluish-green pigment (a probable siderophore) extracted from the spores showed an absorption maximum at 292 nm. To sum up, the complete lignocellulolytic potential of this fungus offers great industrial significance, coupled with the production of a new pigment.

关键词： Trichoderma viride Morphology Liquid Fermentation Bluish-Green Pigment