摘要
基因工程菌株Klebsiella pneumoniae厌氧发酵过程中,氧化还原电位(ORP)是一个监控发酵过程的重要指标.考察了K.pneumoniae F-1在不同ORP(-190,-210,-240和-290mV)下菌体生长和代谢产物合成的情况.在ORP为-240mV时,1,3-丙二醇的发酵终浓度和得率分别为81.5g/L和0.423mol/mol,分别为4种ORP条件下的最高值.这说明ORP=-240mV是菌株K.pneumoniae F-1的最适ORP.此ORP既不同于野生菌株K.pneumoniae M5aL的最适ORP(-190mV),也不同于经过诱变的菌株K.pneumoniae YMU2的最适ORP(-280mV).另外,通过研究发酵体系ORP对甘油代谢流的影响,发现还原性氛围较有利于甘油向1,3-PD、乙醇、2,3-丁二醇等还原性较高的代谢物转化.首次报道了ORP调控发酵过程在基因工程改造菌株中的应用,这对于进一步研究ORP调控厌氧发酵过程具有一定的意义.
Redox potential （also called oxidoreduction potential, ORP） is one of important indicators to monitor the anaerobic fermentation of Klebsiellapneumoniae. In this report, the preferred ORP of a recombinant strain K. pneumoniae F-1 was investigated by controlling the ORP of broth into four levels of-190, -210, -240 and -290 mV. The results showed that in the fermentation of ORP at -240 mV, the highest final 1,3-propanediol concentration and molar yield of were achieved, being 81.5 g/L and 0.423 mol/mol, respectively. This preferred ORP to the genetic modified strain was different from those of both the wild strain K. pneumoniae MSaL （-190 mV） and the mutant K. pneumoniae MSaL YMU2 （-280 mV）. It is demonstrated that the modification of the metabolic pathway in the K. pneumoniae F-1 exerted effects on the preferred ORP of the strain. The effect of ORP on re-distribution of the metabolites was also investigated. The results demonstrated that the reduction environment facilitated the pathways from glycerol to reduction end-metabolites, such as 1,3-propanediol, ethanol and 2,3-butanediol. This work is the first investigation on the ORP regulation method in a recombinant strain, which will provide insight into the mechanism of ORP regulation in anaerobic fermentations.
出处
《过程工程学报》
EI
CAS
CSCD
北大核心
2007年第5期1014-1017,共4页
The Chinese Journal of Process Engineering
基金
国家重点基础研究发展规划(973)基金资助项目(编号:2003CB716007)
福建省自然科学计划基金资助项目(编号:2007J0287)
