oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 1 )

2019 ( 33 )

2018 ( 397 )

2017 ( 472 )

Custom range...

Search Results: 1 - 10 of 33791 matches for " SHI Xian-ai "
All listed articles are free for downloading (OA Articles)
Page 1 /33791
Display every page Item
Asymmetric Reduction of 3-Chloropropiophenone with Saccharomyces cerevisiae in Aqueous System
水相中酿酒酵母催化3-氯-1-苯丙酮的不对称还原反应

YANG Jin,FANG Shi-yin,SHI Xian-ai,
杨锦
,方世银,石贤爱

过程工程学报 , 2011,
Abstract: 实验考察了水相体系中酿酒酵母细胞对3-氯-1-苯丙酮不对称还原的影响. 结果表明,该反应的优势产物为(S)-3-氯-1-苯丙醇,且反应是由单一酶或具有相同催化特性的同工酶催化的. 在实验浓度范围内,该反应不存在底物抑制和产物抑制,但产物对细胞存在毒性而导致细胞失去催化能力,影响产物得率的提高. 当反应体系中Tween-80浓度为2.0 mmol/L, b-环糊精浓度为5.0 mmol/L时,得率从对照组的64.7%分别提高到73.8%和70.6%. 说明同时具有包结作用和改善细胞膜渗透性的Tween-80提高产物得率的效果优于仅具有包结作用的b-环糊精.
Cloning and Sequence Analysis of Cellulase Genes from Trichoderma longibrachiatum
长梗木霉纤维素酶基因的克隆及序列分析

SHI Xian-Ai,LIU Yue,CHEN Fei,YANG Jin,
石贤爱
,刘月,陈飞,杨锦

微生物学通报 , 2010,
Abstract: Strain FU05 with cellulose-degrading activity was isolated from cellulose-rich environment and identified as Trichoderma longibrachiatum through morphology characteristics and ITS sequence analysis. The cellulase genes bgl2, cbh2 and eg1 were cloned by PCR. By conducting sequence alignment analysis with the reported data it was found that the homology of same cellulase genes between strain FU05 and other Trichoderma were: 91% to bgl2 (AB003110) from Trichoderma reesei; 99% to cbh2 (DQ504304) from Trichoderma koninqii and 95% to eg1 (X60652) from Trichoderma longibrachiatum. Furthermore, the corresponding amino acid sequences were also quite similar. By means of PROSITE motif search, the locations of N-glycosylation site, cellulose-binding domain and conserved domains of glycosyl hydrolases family in the corresponding protein were confirmed.
Effects of 2-phenylethanol on physiological and biochemical characteristics of Saccharomyces cerevisiae
2-苯乙醇对酿酒酵母生理生化特性影响

Wang Hang,Meng Chun,Shi Xian-Ai,Guo Yang-Hao,
王航
,孟春,石贤爱,郭养浩

微生物学通报 , 2012,
Abstract: Objective] To provide useful basis for enhancing the biosynthesis of 2-phenylethanol (PEA), we studied the variation of physiological and biochemical characteristics of Saccharomyces cerevisiae sp. strain R-UV3 treated on varied concentrations of PEA. Methods] Morphological observation was performed by a transmission electron microscope. Membrane permeabilization, intracellular reactive oxygen species (ROS) and mitochondrial membrane potential after staining with propidium iodide, dihydroethidium and rhodamine 123 respectively were investigated at the single-cell level with flow cytometry. The expression of aro10 gene was determined by real-time fluorescence quantitative PCR. Results] With the increasing PEA concentration (0?4.0 g/L), the membrane permeabilization, glycometabolism and expression of aro10 gene in the yeast cell decreased and mitochondrial membrane potential increased. ROS increased when PEA concentration was below 3.0 g/L and decreased when PEA concentration was beyond 3.0 g/L. The physiological and biochemical characteristics of the yeast, such as membrane permeabilization, glycometabolism and expression of aro10 gene, varied notably as PEA concentration increased from 2.4 g/L to 3.0 g/L. Conclusions] The aqueous PEA concentration should be controlled at 2.4?3.0 g/L when in situ PEA removal technology was performed.
Biosynthesis of 2-Phenylethanol by Saccharomyces cerevisiae sp.Strain with ISPR Technology
原位转移技术用于酵母合成2-苯乙醇

GUANG Ang,WANG Hang,MENG Chun,SHI Xian-ai,GUO Yang-hao,
关昂
,王航,孟春,石贤爱,郭养浩

过程工程学报 , 2009,
Abstract: 研究了酵母转化L-苯丙氨酸(Phe)合成2-苯乙醇(Pea)的常规和带原位转移的补料分批培养过程特性. 在常规培养中,以优化补料策略将糖浓度控制在0.1~0.3 g/L,使副产物乙醇浓度小于1%,而Pea的最高终浓度仅为3.85 g/L,因产物抑制效应无法获得更高浓度. 采用大孔树脂FD0816作为原位转移产物的介质,Pea最终总浓度达到12.80 g/L,平均生成速率为0.38 g/-L(h),比未添加树脂的培养体系分别提高了232%和35.7%. 采用乙醇溶液对发酵用的树脂进行动态洗脱,Pea洗脱率达到95%以上,洗脱液中Pea浓度达到60 g/L.
Optimization and Kinetics of the Fed-batch Bioconversion from L-phenylalanine to 2-Phenylethanol via Saccharomyces cerevisiae
酿酒酵母转化生成2-苯乙醇分批补料工艺优化

WANG Hang,DONG Qing-feng,MENG Chun,SHI Xian-ai,GUO Yang-hao,
王航
,董清风,孟春,石贤爱,郭养浩

过程工程学报 , 2010,
Abstract: 对酿酒酵母转化生成2-苯乙醇过程的碳氮源进行优化,选择葡萄糖为碳源,1 g/L脲为氮源,8 g/L L-苯丙氨酸为前体,以呼吸商达1.1±0.1为补糖控制依据,在5 L发酵罐水平建立分批补料工艺,2-苯乙醇终浓度达4.39 g/L,生成速率达0.314 g/(L×h),L-苯丙氨酸摩尔转化率为0.8,L-苯丙氨酸残留浓度仅为0.634 g/L.
Process Characteristics of Bioleaching Meizhou Chalcopyrite by Thermophilic Acidianus brierleyi
嗜热布氏酸菌对梅州黄铜矿的生物浸出过程特性

SHI Xian-ai,LI Cong-ying,LIN Hui,MENG Chun,GUO Yang-hao,
石贤爱
,李聪颖,林晖,孟春,郭养浩

过程工程学报 , 2005,
Abstract: 研究了嗜热布氏酸菌对梅州黄铜矿的浸出机理和浸出过程特性.嗜热布氏酸菌(简称A.B菌)在梅州黄铜矿表面的吸附过程符合朗格缪尔等温线,最大吸附量XAm5.00×108cell/g,吸附平衡常数KA5.88×10?7mL/cell.梅州黄铜矿的浸出主要是通过A.B菌的直接氧化起作用.单独A.B菌处理时,铜浸出速率为0.0137g/(L?h),是Fe3+化学氧化速率的6倍.A.B菌(65℃)对梅州黄铜矿的浸出速率是常温氧化亚铁硫杆菌(简称T.F)的16倍(31℃).A.B菌生长和浸矿的最适温度均为65℃,微生物生长最佳pH为2.0,而浸矿最适pH为1.5.A.B菌处理10d可使铜浸出率达91.3%,具有潜在的工业应用价值.
Ecological treatment of organic wastewater by terraneous Ipomoea aquatica Forsk
陆生植物菜用于有机废水的生态治理研究

MENG Chun,SHI Xian-Ai,CHEN Jian-Feng,KE Xiu-Xing,GUO Yang-Hao,
孟 春
,石贤爱,陈剑锋,柯秀兴,郭养浩

中国生态农业学报 , 2007,
Abstract: The effect of wastewater treatment by terraneous Ipomoea aquatica Forsk was studied.Ipomoea aquatica Forsk shows positive removal effect on organic nitrogen and COD.Under aerating conditions,Ipomoea aquatica Forsk can remove 90% or more COD when feeding COD concentration is 1300mg/L, with a maximum removal capacity of 10.56g/L·d when feeding COD concentration is 2600mg/L.Inorganic and organic nitrogen removal rate can reach,respectively 94% and 73% or more.Compared with Eichhornia crassipes Solms,Ipomoea aquatica Forsk has better acclimatization and is more efficient for biodegradation of piggery wastewaters.
Kinetic Characteristics of Antibiotic Sisomicin in a Batch Fermentation Process
西索米星分批发酵的动力学特性

CHEN Jian-feng,ZHANG Yuan-xing,GUO Yang-hao,MENG chun,SHI Xian-ai,CHEN fan,
陈剑锋
,张元兴,郭养浩,孟 春,石贤爱,陈 凡

过程工程学报 , 2005,
Abstract: The sisomicin production was found to be non-associated with the cell growth of M. inyoensis F003. When starch was used as main carbon source, the maximal specific growth rate was 0.058 h?1, and the maximal specific sisomicin production rate was 0.0018 g/(g?h). The cells of M. inyoensis F003 grew well at 10.0~25.0 g/L maltose or 7.5~15.0 g/L glucose in fermentation broth. It was shown by HPLC analysis and enzymatic measurement that maltose was the main fermentable sugar during the fermentation, and sisomicin biosynthesis was limited when the level of fermentable sugar was below 10.2 g/L. The apparent activity of starch-hydrolytic enzymes in the batch fermentation of M. inyoensis F003 was 1/4 to 1/20 fold of the maximum value 0.84 g/(L?h) in sisomicin biosynthesis phase, its apparent activity, which would result in restriction to the sisomicin biosynthesis by the limitation of fermentable sugar in the broth. Sisomicin above 0.5 g/L was inhibitive to its biosynthesis.
Optimization of Fermentation Conditions on Sisomicin Biosynthesis
西索米星发酵工艺条件的优化

CHEN Jian-feng,CHEN Hao,ZHANG Yuan-xing,GUO Yang-hao,MENG chun,SHI Xian-ai,
陈剑锋
,陈浩,张元兴,郭养浩,孟春,石贤爱

过程工程学报 , 2006,
Abstract: The effects of cobaltous chloride, methionine, phosphate and fermentable sugar on sisomicin biosynthesis in a batch fermentation process were investigated. Fermentation conditions of sisomicin biosynthesis in a batch fermentation process were optimized. It was found that the supplementation with some components in medium was significant to sisomicin production. Methylation of precursor gentamicin A in sisomicin biosynthesis was stimulated by 6-10 mg/L cobaltous chloride or 1.0-2.0 g/L methionine. The best time of methionine supplementation was in the pre-middle stage of sisomicin biosynthesis. High phosphate concentration would result in high pyruvic acid concentration and amylase activity, and low alkaline phosphatase activity and sisomicin concentration. It is beneficial to sisomicin biosynthesis that the phosphate concentration is controlled under 3.14 mmol/L in cell growth phase and below 0.10 mmol/L in sisomicin biosynthesis phase. Compared with that in the batch fermentation, while fermentable sugar was controlled in 8.5-11.5 g/L, either at constant or varying maltose feeding rate or at constant starch hydrolysate feeding rate, the ferment level of sisomicin in the fed-batch fermentations was distinctly increased.
Influencing Factors of Asymmetric Biosynthesis of R-(-)-mandelic Acid
生物不对称合成R-(-)-扁桃酸的影响因素

XIAO Mei-tian,HUANG Ya-yan,SHENG Jun,MENG Chun,SHI Xian-ai,GUO Yang-hao,
肖美添
,黄雅燕,盛军,孟春,石贤爱,郭养浩

过程工程学报 , 2004,
Abstract: R-(-)-mandelic acid is an important multifunctional pharmaceutical intermediate in the preparation of chiral drugs. A sp. strain by1 from 18 strains of Saccharomyces cerevisiae, Lactoballius, Streptococcus faecalis, Candida albicans had been screened for transforming phenylglyoxilic acid to R-(-)-mandelic acid. In this article, to study further the asymmetric bioreduction of phenylglyoxylic acid to mandelic acid by Saccharomyces cerevisiae sp. strain by1, the effect of biochemical factors on the conversion efficiency of substrate phenylglyoxylic acid and enantiomeric excess of product R-mandelic acid were investigated in detail. For some conditions tested in our experiments, the sp. strain by1 showed very high enantioselectivity toward the bioreduction of the substrates. The enantiomeric excess value of desired product R-(-)-mandelic acid reached up to 94.0%. Whereas, the conversion of substrate and the yield of product mandelic acid were influenced evidently by the environmental factors. The substrate conversion and the yield of product decreased sharply with the increase of initial substrate concentration up to 20 mmol/L. The high concentration of substrates inhibits strongly the activity of redoxase of yeast cells. Under the optimal conditions: pH 6.5, 32oC, initial concentration 15 mmol/L, absolute anaerobic cultivation 28 h, the substrate conversion rate of 97.0% and yield of product mandelic acid of 96.1% and enantiomeric excess value of R-(-)-mandelic acid of 95.1% could been obtained. This research paces the way for economic preparation of chiral R-(-)-mandelic acid.
Page 1 /33791
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.