摘要
研究了重组大肠杆菌JM001(△ppc)/pTrc99a-pck发酵产琥珀酸的性能,结果表明厌氧条件下其耗糖能力和产酸能力分别为对照菌株JM001的4.2倍和15.3倍。进一步优化发酵条件表明:采用接入菌泥的发酵方式比按照10%接种量转接厌氧发酵的效果要好,琥珀酸的对葡萄糖的质量收率提高了约10%,且副产物乙酸的量进一步降低。初始葡萄糖浓度高于60g/L时会对菌株的生长和产酸产生抑制,且浓度越高,抑制作用越明显。7L发酵罐放大实验中,整个厌氧发酵阶段葡萄糖的消耗速率为0.42g/(L·h),琥珀酸对葡萄糖的质量收率为67.75%,琥珀酸的生产强度为0.28g/(L·h)。
The fermentation characteristics of recombinant E.coli JM001（△ppc）/pTrc99a-pck for succinate production was investigated.The results showed that its glucose consumption and succinate production rates were 4.2 and 15.3 folds as much as those of the parent strain E.coli JM001,respectively.The mass yield of succinate to glucose was 54%,besides the acetic acid concentration was rather low.It could be concluded that the reaction from phosphoenolpyruvate （PEP） to oxaloacetic acid （OAA） catalyzed by PEP carboxykinase （PCK） was more beneficial to the cell growth and succinate production compared to PEP carboxylase （PPC）.Further investigation was carried out to optimize the fermentation conditions.The results showed that bacterial sludge was much better than 10% （v/v） broth for the inoculation from aerobic phase to the anaerobic one,succinate mass yield increased from 55.2% to 65.1% and the entire time to consume 20g/L glucose reduced to 48h.The results of glucose tolerance experiment showed that between 20g/L and 60g/L initial glucose,cell growth and succinate production were both satisfactory,succinate mass yield was from 64.18% to 69.10% with the increase of glucose concentration.But when the glucose was higher than 60g/L,cell growth and succinate production were clearly repressed.The higher the glucose concentration was,the more obvious the inhibition effects were.For 7L fermentor research,the initial glucose of the anaerobic phase was 40.25g/L,after 96 h it was completely consumed.The succinate mass yield was 67.75%.During the anaerobic phase,the glucose consumption rate was 0.42g/（L·h） and succinate productivity was 0.28g/（L·h）.
出处
《中国生物工程杂志》
CAS
CSCD
北大核心
2010年第9期43-48,共6页
China Biotechnology
基金
国家"973"计划(2009CB724701)
国家自然科学基金(20606017)
江苏省"青蓝工程"资助项目
