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厌氧发酵产氢细菌的分离和鉴定及产氢特性 总被引:1,自引:0,他引:1
获得优良的产氢菌株,鉴定并研究其产氢特性,为提高其产氢能力提供基础。对样品进行预处理和葡萄糖梯度驯化处理后,采用厌氧培养技术分离单菌落,进行菌株形态学观察、生理生化试验及16S rDNA分子生物学鉴定,并采用分批式厌氧发酵研究其产氢特性。结果表明:其中产氢最优的菌株FML-C1为肠杆菌属细菌,葡萄糖为其产氢的最优碳源,氮源则以酵母粉和蛋白胨混合最佳,最适生长和产氢温度为35℃,最佳初始pH值为6.0,该条件下菌株的气相末端产物中氢体积分数达56.51%。菌株FML-C1为一株良好的厌氧发酵产氢菌,可进一步优化其产氢工艺,以提高其产氢能力。 相似文献
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Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ). 相似文献
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The kinetics of batch and fed-batch cultures of recombinant Escherichia coli producing human-like collagen was investigated. In the batch culture, a kinetic model of a simple growth-association system was concluded without consideration of cell endogeneous metabolism. The cell lag time, the maximum specific growth rate and growth rates were set at (0.15, 0.2, 0.25h-1) by the method of pseudo-exponential feeding, and the expressions for the specific rate of substrate consumption, the growth kinetics and the product formation kinetics of each phase spectively. The model predictions are in good agreement with the experimental data. 相似文献
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用滤纸赫奇逊固体培养基和纤维素固体培养基初筛,再以滤纸无机盐培养基和以羧甲基纤维素为唯一碳源的刚果红培养基进行复筛的方法,确定出10株降解效果较好的菌,通过对其纤维素酶相关性质及酶活力进行测定,综合比较降解能力,最终获得6株降解活性较强的菌,其酸性纤维素酶活较强,最优产酶时间为6d,最后采取了非等温同时糖化发酵法(Nonisothermal Simultaneous Saccharification and Fermentation,NSSF)和同步糖化发酵法(Simulta-neous Saccharification and Fermentation,SSF)进行乙醇发酵,结果表明NSSF的乙醇产率大于SSF. 相似文献
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Recombinant Escherichia coli BL21 is used to produce human-like collagen. The key constituents of media are optimized using response surface methodology (RSM). Before thermal induction, the highest biomass production and the lowest production of some hazardous by-products, especially acetic acid, were obtained in the media containing 0.085 mol∙L1 glucose and 0.019 mol∙L1 nitrogen (carbon-nitrogen ratio, 4.47︰1). After thermal induction, when the concentrations of glucose and nitrogen in the media were 0.065 mol∙L1 and 0.017 mol∙L1, respectively (carbon-nitrogen ratio, 3.82︰1), the productivity of human-like collagen per cell was the highest while that of acetic acid was the lowest. The extended analysis showed that the production of lactic acid and propionic acid increased while that of some intermediate acids of the tricarboxylic acid cycle decreased if the dose of glucose in-creased. 相似文献
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In order to improve the production of human-like collagen Ⅲ (HLC Ⅲ) by fed-batch culture of recom-binant Escherichia coli BL21, the Plackett-Burman and Box-Behnken design were applied to optimize the fermen-tation process parameters.Three variables (induction time, inoculum age and pH), which have significant effects on HLC Ⅲ production, were selected from eight variables by Plackett-Burman design.With the regression coefficient analysis in the Box-Behnken design, a relationship between HLC Ⅲ production and three significant factors was obtained, and the optimum levels of the three variables were as follows: induction time 3.2h, inoculum age 12.6 h and pH 6.7.The 3D response surface plots and 2D contour plots created by the Box-Behnken design showed that the interaction between induction time and pH and that between innoculum age and pH were significant.An aver-age 9.68 g·L~(-1)HLC Ⅲ production was attained in the validation experiment under optimized condition, which was 80% higher than the yield of 5.36 g·L~(-1) before optimization. 相似文献
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类人胶原蛋白Ⅱ的离子交换吸附平衡研究 总被引:1,自引:1,他引:0
研究重组类人胶原蛋白Ⅱ(RHLCⅡ)在CM52树脂上的吸附平衡,考察pH值、NaCl浓度及温度对吸附平衡的影响。结果表明:当4.0pH≤5.0时,随着pH值增大,吸附容量减小,解离系数Kd增大;当3.0≤pH4.0时,随着pH值增大,吸附容量增大,解离系数Kd减小;随着NaCl浓度增大,吸附容量减小,解离系数Kd增大;温度对Langmuir方程参数的影响较小,温度每升高10℃,吸附容量增加3%左右,解离系数Kd的变化不显著。RHLCⅡ在CM52树脂上的吸附基本符合Langmuir方程,为离子交换法规模制备RHLCⅡ提供了理论依据。 相似文献