不同预处理及发酵方式对提高蔗渣发酵产物蛋白含量的研究

采用不同的预处理方法对蔗渣进行预处理,并测定了其各个组分的含量。利用霉菌对蔗渣进行微生物降解,并讨论了不同发酵方式对产物中蛋白含量的影响。结果表明,木霉与热带假丝酵母共发酵时蛋白含量最高,为17．74％。     

诱变筛选荧光假单胞菌M18高产吩嗪-1-羧酸(PCA)菌株及发酵条件研究

研究了亚硝基胍(NTG)的诱变剂量、处理时间以及氯化钠浓度对野生型荧光假单胞菌M18存活率的影响,NTG的诱变剂量25～200mg／L,处理时间10～30min范围内,随着诱变剂剂量增加和时间的延长,M18的存活率不断下降。NTG的作用剂量25mg／L,处理时间10min时,细菌存活率为55％左右。利用细菌存活率为55％时的诱变条件,经生物测定,初筛获得20株抑菌效果明显的诱变株。经摇瓶发酵复筛,从这20株诱变株中,获得PCA高产诱变株M18N07。并对此菌株发酵条件进行调整,较理想的培养条件为：蛋白胨18g／L,葡萄糖16g／L,氯化钠1g／L,硝酸钾10g／L。小瓶培养时间17h,大瓶5％接种量,28℃培养54h。     

鼎湖山马尾松、荷木混交林生态系统碳素积累和分配特征

选取鼎湖山保护区3个马尾松9Pinus massoniana),荷木（Schima superba)针阔混交林样地,研究其生态系统的碳素积累和分配特征。结果表明,鼎湖山马尾松,荷木混交林乔木尾生物量（thm^-2)为：174.41-270.11。平均227.36,且均以马尾松的生物量居多（占54.9%-84.4%)。林下层植物生物量和地表现存凋落物量（thm^-2)分别为7.41-28.28和7.06-11.56。平均14.41和9.03。三个混交林生态系统总碳贮量（thm^-2)分别为146.35,215.30和205.79。平均为189.15,其中植被层碳贮量贡献率最大,依次占62.9%,61.9%和69.9%。平均65.0%;土壤层贡献率次之,依次占34.3%,35.5%和28.5%。平均32.8%;而地表现存凋落物层的贡献最小,仅占2.8%,2.6%和1.6%。平均为2.3%。此外,本文还对该生态系统植被碳吸存潜力进行了讨论。     

黑曲霉固态发酵木聚糖酶中试条件的研究

通过对黑曲霉在曲盘中进行固态发酵木聚糖酶中试条件进行优化研究,结果表明最适的产酶培养基中麸皮与玉米芯比例为6:4,添加硫酸铵可以促进黑曲霉菌丝生长,对酶活没有显著影响;最适的培养基初始pH值为4.0,培养基厚度为4cm;在28℃下培养60～84h,木聚糖酶活稳定在最高峰。     

丙酮酸对细菌L-乳酸发酵的促进作用

研究了丙酮酸在不同浓度和添加时间对LactobacilluscaseiL 乳酸发酵过程中葡萄糖转化率和L 乳酸产量的影响。结果表明 ,当丙酮酸的添加量为 30g·L- 1 时 ,L 乳酸的产量达到 74g·L- 1 。在 72h的发酵周期内 ,丙酮酸在 2 4h和 42h添加的效果好于其他时间添加。     

低分子量羊胎提取液RP-HPLC分析方法的初步研究

采用RP -HPLC法在ODSHypersil柱上分析低分子量羊胎提取物中的活性成分。通过多种色谱参数的比较 ,探讨了流动相、梯度、流速、温度、波长对混合未知成分分离的影响 ,获得最佳色谱条件。对其重现性进行考察 ,发现各峰保留时间的相对标准偏差均可控制在 0 .3%以下 ,峰面积则在 2 .0 %以内。说明该研究能够有效的针对动物提取的混合成分 ,建立一种准确可靠的RP -HPLC分析方法 ,为质量标准的控制提供了新的测定指标。     

环境因素对L-异亮氨酸发酵的影响

通过 5L自控发酵罐发酵实验 ,结合发酵过程中菌生长形态的变化 ,对L -异亮氨酸补料分批发酵进行研究 ,研究了环境因素对黄色短杆菌 (Brevibacteriumflavum)TJCN - 1的影响 ,优化出发酵最佳控制条件 ,提出分阶段发酵控制模式 ,对L -异亮氨酸生产有指导意义。     

Production of acetone,butanol and ethanol by Clostridium beijerinckii BA101 and in situ recovery by gas stripping

We examined the effect of gas-stripping on the in situ removal of acetone, butanol, and ethanol (ABE) from batch reactor fermentation broth. The mutant strain (Clostridium beijerinckii BA101) was not affected adversely by gas stripping. The presence of cells in the fermentation broth affected the selectivities of ABE. A considerable improvement in the productivity and yield was recorded in this work in comparison with the non-integrated process. In an integrated process of ABE fermentation-recovery using C. beijerinckii BA101, ABE productivities and yield were improved up to 200 and 118%, respectively, as compared to control batch fermentation data. In a batch reactor C. beijerinckii BA101 utilized 45.4 g glucose l^–1 and produced 17.7 g total ABE l^–1, while in the integrated process it utilized 161.7 g glucose l^–1 and produced total ABE of 75.9 g l^–1. In the integrated process, acids were completely converted to solvents when compared to the non-integrated process (batch fermentation) which contained residual acids at the end of fermentation. In situ removal of ABE by gas stripping has been reported to be one of the most important techniques of solvent removal. During these studies we were able to maintain the ABE concentration in the fermentation broth below toxic levels.     

Optimization of fermentation conditions for the production of ethanol from sago starch using response surface methodology

The quantitative effects of temperature, pH and time of fermentation were investigated on simultaneous saccharification and fermentation (SSF) of ethanol from sago starch with glucoamylase (AMG) and Zymomonas mobilis ZM4 using a Box–Wilson central composite design protocol. The SSF process was studied using free enzyme and free cells and it was found that with sago starch, maximum ethanol concentration of 70.68 g/l was obtained using a starch concentration of 140 g/l, which represents an ethanol yield of 97.08%. The optimum conditions for the above yield were found to be a temperature of 36.74 °C, pH of 5.02 and time of fermentation of 17 h. Thus by using the central composite design, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.     

温度对谷胱甘肽分批发酵的影响及动力学模型

研究了24～32℃范围内产朊假丝酵母生产谷胱甘肽的分批发酵过程,发现较高温度对细胞生长有促进作用,而较低温度则更有利于谷胱甘肽产量的提高。应用改进的Logistic和LuedekingPiret方程分别对细胞生长动力学和谷胱甘肽合成动力学进行了模拟,得到不同温度下各种动力学参数。在此基础上,进一步研究了温度同细胞生长动力学参数之间的内在联系,得到谷胱甘肽分批发酵过程中细胞浓度的变化同温度以及底物浓度之间的一般关系式：dX-dt＝［0.0224(T+1.7)］2X(1-X/X_max)1+S｛8.26×10.6×exp［-31477/R/(T+273)］｝。验证实验结果表明,该模型具有很好的适用性。