热带假丝酵母及其重组菌产十三碳二元酸的补糖发酵实验

利用热带假丝酵母原始菌F10-1及已构建的肉毒碱乙酰转移酶基因单拷贝缺失重组菌CZ-15,在5 L发酵罐中进行了补糖发酵批式培养,生产十三碳二元酸(DCA13). 结果表明,肉毒碱乙酰转移酶基因单拷贝缺失后,CZ-15菌株的最佳补糖时间和补糖浓度都与原始菌F10-1不同. 采用补糖工艺后,F10-1与CZ-15的十三碳二元酸的产量分别提高了25.0%和23.4%,达到99.5和108.1 g/L,烷烃转化率分别提高了35.5%和28.6%.     

热带假丝酵母肉毒碱乙酰转移酶酶活测定及重组菌的性质

建立了快速部分提纯和测定热带假丝酵母中肉毒碱乙酰转移酶(carnitine acetyltransferase,CAT)酶活的方法.并考察了重组热带假丝酵母的CAT酶活、产酸能力及烷烃转化率.结果表明,重组菌的CAT酶活比原始菌降低了45%,胞内二元酸通过β-氧化的无益消耗得到有效抑制.相应地,重组菌的产酸能力和烷烃转化率分别提高了11%和12%.     

热带假丝酵母发酵生产长链二元酸的节能减排措施

热带假丝酵母发酵生产长链二元酸在菌体、空气、烃类(油)和水的四相发酵体系中完成,发酵过程需氧量大、放热量高,提纯过程多处存在升温、降温过程,生产成本高。采用"倒推法"分析了装置公用工程消耗的主要影响因素,通过节能改造,余热、废汽与废水回收,正常生产每年可节省生产成本390余万元。     

利用热带假丝酵母发酵生产长链二元酸的研究进展

概述了国内外利用热带假丝酵母发酵生产长链二元酸技术的研宪进展。从茵株的选育、发酵工艺的优化、提纯工艺研究等方面分析了现有技术特点,并针对以上3个方面提出有待进一步研究的问题。     

不同氮源对热带假丝酵母处理苎麻生物脱胶废水的影响

利用热带假丝酵母(C.tropicalis)处理苎麻生物脱胶废液,研究了不同种龄及不同氮源(尿素、草酸铵、硫酸铵、磷酸氢二铵、氯化铵)条件下,热带假丝酵母对苎麻生物脱胶废水的处理效果及单细胞蛋白的产量(以菌体干重计)。结果表明:种龄对于废水COD去除率的影响不大,但对单细胞蛋白生成量的影响较大,兼顾二者,以28 h种龄的菌的处理效果最佳;在试验供试的替代氮源中,磷酸氢二铵对于苎麻脱胶废水COD的去除和单细胞蛋白的产量最为有效,是替代蛋白胨的理想氮源。     

克鲁斯假丝酵母分批发酵生产甘油的代谢流分布

采用Candida krusei分批发酵生产甘油，在碳元素平衡基础上作代谢流分析得知，典型生长阶段（6－12h)形成菌体流量较大，占50％以上，且有12％的乙醇流量，甘油流量较小：典型生产阶段（48－54h)甘油流量增大为42%，菌体和乙醇流量为0，有11％的有机酸流量。     

利用β-氧化抑制剂提高长链二元酸的产率

本文通过热带假丝酵母 (Candidatropicalis)氧化正十三烷发酵生产十三碳二元酸 ,考察了 3种 β 氧化抑制剂对菌体生长及产酸的影响。结果表明 ,抑制剂 2 Bromooctanoicacid(BA)作用效果比较显著 ,在适宜浓度范围内BA对菌体生长影响不大 ,但对产酸有一定的促进作用。利用生长细胞发酵 ,BA浓度为 0 5mmol/L时发酵产率最高 ,比对照提高 6 1% ;利用休止细胞发酵 ,其浓度为 5mmol/L时发酵产率最高 ,比对照提高 4 5 % ,但比产酸速率受到一定影响 ;15L发酵罐实验表明 ,加入适量的抑制剂BA对二元酸积累有促进作用     

温度对产甘油假丝酵母产甘油发酵过程的影响

研究了温度对产甘油假丝酵母分批发酵生产甘油及其生长动力学的影响。结果表明:在温度为28—36℃时,由于发酵周期随温度升高而显著缩短,导致细胞生长、甘油合成和葡萄糖消耗的比速率也随温度升高逐渐增加;当温度为32℃时最适于产甘油假丝酵母合成甘油,甘油产量、得率和产率分别达到120.3 g/L,0.523 g/g,1.43 g/(L.h);应用Logistic方程对细胞生长动力学进行了模拟,获得不同温度下的生长动力学参数;根据细胞生长动力学参数,得到28—36℃时甘油分批发酵过程中细胞质量浓度同温度、时间之间的一般关系式,经验证该模型在28—36℃范围内可用于预测不同温度下的细胞生长情况。     

He-Ne激光诱变高活力苯酚降解菌热带假丝酵母CT43的研究

运用He—Ne激光辐照热带假丝酵母(Candida tropicalis)对激光诱变参数进行优化,考察了突变株的遗传稳定性和降酚特性。结果表明：经过激光辐照处理的热带假丝酵母CT43降解2000mg／L的苯酚仅需要54．5h,降解效率显著提高。表明He-Ne激光诱变育种技术可以在环境微生物领域中应用。     

培养条件对产朊假丝酵母合成谷胱甘肽的影响

考察了培养基组成,培养条件对产朊假丝酵母生长和谷胱甘肽合成的影响,包括不同碳源,氮源及其浓度,pH,装液量,接种量等。确定以葡萄糖、磷酸氢二铵作为碳源和氮源,较佳浓度分别为20g/L和3g/L,接种量为10％,在20 g/L 的糖 浓度时获得的谷胱甘肽总量可达74mg/L,胞内含量为1.4％左右。此外还研究了三种前体氨基酸和ATP的加入量,加入时间对发酵的影响。     

十三碳二元酸发酵与肉毒碱乙酰基转移酶酶活动力学研究

在利用热带假丝酵母发酵生产十三碳二元酸(DCA13)的过程中,建立了用荧光法测定酵母体内肉毒碱乙酰基转移酶(CAT)酶活的方法,方法简单,重现性高,测量精确。研究了热带假丝酵母中CAT酶活动力学与产酸速率的关系,结果表明:代谢前期细胞以生长为主,CAT酶活较高可提供更多的生长动力,而代谢后期细胞进入产酸期,CAT酶活与产酸速率的变化趋势成反比,即产酸速率高时,CAT的酶活较低。     

Modelling of phenol biodegradation by Candida tropicalis immobilised in alginate gel beads

Phenol‐degrading yeast Candida tropicalis were immobilised in alginate gel beads and photographed by scanning electron microscopy. Batch phenol biodegradation experiments were done in shaking flasks under varying conditions such as initial phenol concentrations and bead loadings. A mathematical model was proposed to simulate the batch phenol biodegradation process in the immobilised system, which took into account the internal and external mass transfer resistances of phenol and oxygen and the double‐substrate phenol–oxygen intrinsic kinetics. The validation of this model was done by the comparison between the model simulations and the experimental measurements of phenol concentration profiles in the main liquid phase. Moreover, the time and radius courses of phenol, oxygen, and cell concentration profiles within the alginate gel beads were reasonably predicted by the proposed model.     

The Arylamidine T-2307 as a Novel Treatment for the Prevention and Eradication of Candida tropicalis Biofilms

Candida tropicalis is an emerging pathogen with a high mortality rate due to its virulence factors, including biofilm formation, that has important repercussions on the public health system. The ability of C. tropicalis to form biofilms, which are potentially more resistant to antifungal drugs and the consequent increasing antimicrobial resistance, highlights an urgent need for the development of novel antifungal. The present study analyzed the antibiofilm capacity of the arylamidine T-2307 on two strains of Candida tropicalis. Antimicrobial activity and time-killing assays were performed to evaluate the anticandidal effects of T-2307, the antibiofilm ability on biomass inhibition and eradication was evaluated by the crystal violet (CV) method. Furthermore, in Galleria mellonella infected larvae an increased survival after pre—and post- treatment with T-2307 was observed. The MTT test was used to determine the viability of immortalized human prostate epithelial cells (PNT1A) after exposure to different concentrations of T-2307. Levels of interleukin IL-4, IL-8, IL-10 were quantified after Candida infection of PNT1A cells and treatment. Active doses of T-2307 did not affect the viability of PNT1A cells, and drug concentrations of 0.005 or 0.01 µg mL⁻¹ inhibited the secretion of inflammatory cytokines. Taken together, these results provide new information on T-2307, indicating this drug as a new and promising alternative therapeutic option for the treatment of Candida infections.     

热带假丝酵母不对称还原3,5-双三氟甲基苯乙酮制备手性醇(英文)

(S)-3,5-bistrifluoromethylphenyl ethanol is a key chiral intermediate for the synthesis of NK-1 receptor antagonists. Enantioselective synthesis of (S)-3,5-bistrifluoromethylphenyl ethanol was successfully performed in high enantiomeric excess (e.e.) through asymmetric reduction of 3,5-bis(trifluoromethyl) acetophenone catalyzed by Candida tropicalis 104 cells. The influence of some key reaction parameters such as substrate concentration, co-substrate and its concentration, biomass and reaction time was examined, respectively. The results showed that these factors obviously influence the yield, but the optical purity of the prepared product remains intact. The opti-mum conditions for the preparation of (S)-3,5-bistrifluoromethylphenyl ethanol were found to be as follows: sub-strate concentration 50 mmol?L?1; 50 g·L-1 of maltose as co-substrate; wet cell concentration 300 g·L-1; reaction for 30 h. Under above optimal conditions, the maximum yield for (S)-3,5-bistrifluoromethylphenyl ethanol reached 70.3% with 100% of product e.e.     

溶氧对Candida glycerinogenes产甘油发酵代谢流分布的影响

分析了耐高渗高产甘油工业菌株产甘油假丝酵母(Candida glycerinogenes)的摇瓶发酵过程,发现溶氧水平是影响C.glycerinogenes 生长、代谢产物生成的重要因素。在此基础上,以5 L发酵罐研究了不同恒溶氧水平甘油的合成过程,通过代谢流分析表明,低溶氧环境下乙醇碳流量增加,导致糖耗快而甘油合成相对较少;碳流分布表明HMP途径在甘油过量合成中起着重要的作用。分析C.glycerinogenes发酵过程中能量代谢和物质代谢（氧化磷酸化和底物水平磷酸化）的变化发现高溶氧环境下ATP合成水平高,一定程度抑制底物水平磷酸化从而使碳流更多地流向了甘油合成;C.glycerinogenes胞内氧化还原平衡(NADH/NAD+比率)的研究进一步解释了产甘油假丝酵母中甘油合成和乙醇生成的竞争关系。     

新型生物絮凝剂REA-11的代谢模型建立与代谢网络分析

利用代谢通量分析方法,对谷氨酸棒杆菌Corynebacterium glutamicum CCTCC M201005分批发酵不同阶段和不同溶氧浓度下的代谢网络模型进行了计算,考察了代谢节点对絮凝剂REA-11合成的影响,并对C. glutamicum生长代谢过程中能量和还原力的产生及消耗问题进行分析.结果发现,磷酸戊糖途径(PP)通量在整个发酵过程中始终维持在较高的水平;REA-11合成通量随溶氧浓度的增加而降低,菌体合成通量则随溶氧水平的增加而增加;ATP通量的增加可以促进菌体生长,而与REA-11的合成呈负相关.