重组大肠杆菌分批-补料高密度发酵生产类人胶原蛋白的动力学

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 Yx/s were determined as 1.75h, 0.65h^-1 and 0.51g·g^-1, respectively. In the fed-batch culture, different specific 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 were obtained. The result shows that the concentrations of cell and product can reach 77.5g·L^-1 and 10.2g·L^-1 respectively. The modal predictions are in good agreement with the experimental data.     

类人胶原蛋白基因工程菌生长期动力学模型

研究类人胶原蛋白基因工程菌生长期动力学模型,为优化发酵调控提供理论依据和指导。应用元素衡算和代谢衡算(EMB)方法,建立类人胶原蛋白基因工程菌生长期的动力学模型,并利用线性规划法对动力学模型参数αh和mX进行估算。结果表明,αh和mX分别为1.173 mol/C-mol和2.326 mol/(C-mol.h),该模型能较好地预测重组大肠杆菌生长期的宏观反应速率,且确立了葡萄糖的流加方程。利用EMB方法建立的动力学模型具有重要的应用价值,若要进一步减小氮消耗速率和CO2产生速率预测误差,需要对重组大肠杆菌的代谢网络进行系统分析,建立该模型的修正系数。     

L-半胱氨酸浓度对氧化还原电位和生物产氢过程的影响(英文)

The effects of L-cysteine concentration on biohydrogen production by Enterobacterium Bacterium M580 were investigated in batch cultivation.The experimental results showed that L-cysteine could enhance the cell growth,hydrogen production rate and hydrogen yield when its concentration was less than 500 mg·L-1,while it had negative effects when its concentration was higher than 500 mg·L-1.The hydrogen production was the highest 1.29 mol·mol-1(H2/glucose) when 300 mg·L-1L-cysteine was added into the culture,and the yield was 9.4% higher than that in the control.The oxidation-reduction potential(ORP) ,which was influenced by L-cysteine,also affected hydrogen production.The ORP values were in the range-300 mV to-150 mV when the L-cysteine concentration was higher than 500 mg·L-1.Although the ORP in this range was favorable for hydrogen production,it was not suitable for the biomass growth.Hence,less hydrogen was produced.When the L-cysteine concentration was lower than 500 mg·L-1,the ORP was more suitable for both biomass growth and hydrogen production.In addition,at least 91%glucose was consumed when L-cysteine was added to the culture media,compared to the 97.37% consumption without L-cysteine added.     

学生自主学习生物工程设备基础的教学模式探索

生物工程设备基础是一门集理论和实践于一体的专业必修课，由于该课程信息量大、计算量大、实践性强，且学生缺乏对实物的认识和实践经验，使得该课程存在难教和难学的问题。为了在有限的授课时间内，让学生更好地学习并掌握生物技术产品的工业化生产过程及相应设备的配套设计与选型，我们结合自身教学经验与科研经历，对该课程的教学模式、教学内容、教学方式与方法、考核模式等进行了一系列改革。结果显示，激发学生自主学习的教学模式成效显著。     

重组大肠杆菌高密度发酵生产类人胶原蛋白的过程控制研究

Recombinant E. coli BL 21 was cultivated in high cell density to produce human-like collagen. The effects of the feeding of nitrogen source, controlled by an auto on/off-feeding mode with two different cycles of 0.5min and 4min intervals, oxygen-enrichment methods and inducement strength on the cell yield and human-like collagen production were investigated. The studies showed that nitrogen source feeding in fast cycle could result in higher human-like collagen production than that in slow cycle; and the feedback regulation of glucose, increase of the pressure of fermentation bioreactor, and supply of oxygen-enriched air could all increase cell yield and human-like collagen production. The effects of inducement strength on protein expression were found important. When OD600 reached 90-100, the cultivation temperature was increased to 42℃ to begin induction for 2-3 h, and then shifted to 39℃ for 5-6h induction, the cell density and human-like collagen production could reach 96g·L-1 [DCW (dry cell mass)     

玉米秸秆中半纤维素的高效综合利用

Pretreatment of the corn stover powder by dilute sulphuric acid (solid-liquid ratio 1︰20) at 130°C for 30 min was carried out with 89.09% of the hemicellulose removed. After filtration, the xylose-rich corn stover pretreatment liquid, whose fermentable sugar was from hemicellulose hydrolysis only, consisting of 81.16% xylose and 15.27% glucose, was used to cultivate genetic recombinant Escherichia coli BL21 with human-like collagen (HLC) expression enhanced by 50.00% and 63.71% xylose consumption.     

不同发酵条件对酿酒酵母甘油产量的影响

为提高酿酒酵母的甘油产量,分别考察不同初始葡萄糖和果糖质量浓度、pH值、发酵温度及SO2添加量对酿酒酵母D254甘油产量的影响。对酿酒酵母D254不同发酵初始条件进行单因素试验,其他因素固定条件下,葡萄糖质量浓度180g/L时酵母菌体生长平稳、生长量最高;果糖质量浓度108g/L时酵母甘油产量最高;pH值为3.5更适宜酵母菌体生长和合成甘油;在发酵温度和SO2添加量的单因素试验中也分别得出适宜发酵温度为28℃和适宜SO2添加量为 20mg/L。通过单因素试验,筛选出最利于酿酒酵母D254生长和产甘油的各因素的最佳质量浓度,进行Plackett-Burman发酵条件组合试验,得到发酵条件最佳组合为：初始葡萄糖质量浓度216g/L、果糖质量浓度144g/L、发酵温度32℃、pH 3.0、SO2添加量40mg/L,此条件下,酿酒酵母D254获得最高甘油产量达655.64μmol/L。