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Optimization in Liquid Fermentation Process of Bacillus velezensis DJ1
JIANG Wei;ZHANG Shumei;MA Junxiu;YAN Gengxuan;HU Jihua;WU Haoqiong;On the basis of single-factor experiments, we optimized the medium components and fermentation conditions of Bacillus velezensis DJ1 by orthogonal experiments and response surface methodologies.The optimal medium components are determined as follows: the maltose of 2.5%,the yeast powder of 0.5%,the sodium chloride of 1.0%,and the manganese sulfate of 0.02%.The optimum fermentation conditions are determined as follows: the fermentation time of 23 h, the initial pH value of 8,and the fermentation temperature of 36 ℃.Under above conditions, the OD600 value is 1.819,which is basically consistent with the predicted value of the model, and the amount of effective living bacteria of the fermentation liquid is 2.34×109 CFU·mL-1.
Comparison of Measuring Methods for Activity of Pyruvate Dehydrogenase
HE Ya-hui1,JIANG Ying1,YUAN Jun-lin1, HE Hong-wu2,TAN Hong-liang1, YANG Xu1,DING Shu-mao1(1.Life Science College of Central China Normal University,Wuhan 430079,China;2.Chemistry College of Central China Normal University,Wuhan 430079,China)Several current measuring methods for activity of pyruvate dehydrogenase are compared and studied.The results show that 2,6-DCPIP method is economic and effective with relatively high sensitivity for measuring activity of pyruvate dehydrogenase (E1).The potassium ferricyanide method is the worst as to reaction time and change of phenomena.But 2,6-DCPIP can't be used for measuring activity of pyruvate dehydrogenase complex,whereas CoA method is suitable with good sensitivity.
Preparation and Application of 3-Hydroxypropionaldehyde
ZHANG Feng,XUE Ya-ping,ZHENG Yu-guo(Institute of Bioengineering,Zhejiang University of Technology,Hangzhou 310014,China)3-Hydroxypropionaldehyde(3-HPA),an effective antimicrobial,is extensively used in food preservation and health care.Additionally,it acts as an important intermediate which provides the precursor of a series of compounds including acrolein,acrylic acid and 1,3-propanediol.In this paper,various 3-HPA preparation methods are summarized,among which biotechnological processes are discussed in detail.Finally,the focus and the strategy are also discussed for the future.
Research and Application Progress of Magnetic Mesoporous Silica Microspheres
ZHENG Yang;JIANG Cheng;HAN De-yan;As a new type of composite functional materials,magnetic mesoporous silica microspheres has broad application prospects in many areas.The synthetic methods of magnetic mesoporous silica microspheres in recent years were reviewed in this paper,and its applications in biochemical fields,such as targeted drugs,biological separation,magnetic hyperthermia and immobilized enzyme were demonstrated.
Studies on Coimmobilization of α-Amylase and Glucoamylase by Embedding in Sodium Alginate
GU Xu-jionɡ,LIU Lin,ZHU Wei,LIU Zhi-qianɡ,ZHANG Cheng-li(Institute of Biology and Environmental Engineering,Zhejiang Polytechnic University,Hangzhou 310014,China)Using sodium alginate as the carrier,α-amylase and glucoamylase were coimmobilized by method embedding.The influences of the ratio of two enzymes,pH value and temperature on the stability of coimmobilized system were discussed in detail.And thermostability,storage stability and continuous use stability of the coimmobilization enyme was studied too.
Optimization in Ultrasonic Extraction Process of Dioscin from Dioscorea nipponica Makino by Response Surface Methodology
CUI Jianqiang;AN Xiaoling;YUWEN Yahuan;ZHAO Meimei;TANG Jing;In this paper, we optimized the ultrasonic extraction process of dioscin from Dioscorea nipponica Makino by response surface methodology on the basis of single-factor experiments.The results show that the extraction rate of dioscin can reach 5.18% under the optimum conditions as follows: the ultrasonic power of 540 W,the ethanol volume fraction of 70%,the liquid-solid ratio of 20∶1(mL∶g),and the ultrasonic time of 40 min.
Research Progress of Microbial Degradation of Organochlorine Pesticides
TIAN Yun;YAO Cai-liang;XIAO Wei-zu;TAN Xi-yu;LU Xiang-yang;The organochlorine pesticides have brought great harm to the environment because of the featur of biological accumulation,persistence and high toxicity.The microbial degradation is one of main degradation methods.The types and multi media migration of organochlorine pesticides,the microorganisms of degrading organochlorine pesticides,as well as the microbial degradation mechanism of organochlorine pesticides were summarized.The prospect of microbial degradation of organochlorine pesticides was also presented.
Study on Treating with Acid and Surface Modification by Acetic Anhydride for Cellulose
YU Zhong-xi,GAO Shan-min,XU Pu,QIAO Qing-an,XU Yan-bin(School of Chemistry and Materials Science,Ludong University,Yantai 264025,China)Microcrystalline cellulose(MCC) was prepared from cotton stalks bleached pulps using hydrochloric and sulfuric acid as hydrolysis agent at 100℃ for 30~60 min.The sample properties,such as degree of polymerization(DP),crystallinity index,and thermal stability were studied by means of XRD,TG and IR.In order to improve the disperisibility of MCC,the modified reaction with acetylation was introduced to modify the MCC surface.XRD results showed that the original crystalline type and biphase system still remained in the micronized cellulose,but the crystallinity could not attain to 100%.SEM and TG analysis indicated that the morphology and decomposition temperature of the products treated with hydrochloric and sulfuric acid were different due to the degree of crystallinity,the use temperature could not exceed 270℃.The appropriate condition by acetic anhydride modification was at 60~70℃ for 35 h with the volume ratio of sulfuric acid to water of 1∶8.After surface modification,the crystallinity of MCC remained constant.The dispersibility of the resulting products was improved in the proper solvents to form stable suspensions.
Studies on Structures and Functions of the Cellulase from Bacteria
CHEN Yan-qin~(1), MAO Pei-hong~(2,3), ZENG Xian-xian~(2,3) (1.College of Chemical Engineering,Xinjiang Agricultural University,Urumqi 830052,China; 2. Ion Beam Bio-Engineering Center, Xinjiang University, Urumqi 830008,China; 3. Department of Physics, Xinjiang University, Urumqi 830046,China)This paper reviewed and discussed the recent advance in structure-function of cellulase from bacteria by structure biology and protein engineering, including cellulase compose, the structure-function of catalytic domains and cellulose-binding domains and linker, molecular folding, and the research prospects.
Separation and Identification of Cellulase-Producing Endophytic Fungi from Dalbergia odorifera and Detection of Enzyme-Producing Activity
GAO Yuan;WANG Zhuo;SUN Shiyu;WANG Jinhe;WANG Xin;We isolated and purified a cellulase-producing endophytic fungi JXP2-2 from Dalbergia odorifera,detected the enzyme-producing activity of the strain JXP2-2,and identified it by molecular biology.The results show that the strain JXP2-2 has the strongest enzyme-producing activity when cultured in PDB liquid medium for 4.5 d, and the cellulase activity reaches 84.50 IU·mL-1.The similarity of base between the strain JXP2-2 and Colletotrichum acutatum KX347475 is up to 99%,and it is preliminarily identified as Colletotrichum acutatum.