【摘要】 进行了费氏中华根瘤菌(Sinorhizobium fredii)合成羟基丁酸和羟基己酸共聚体[P(HB-HH)]的研究,通过摇瓶正交试验优化了培养基成分、培养条件和癸酸盐调控条件,采用发酵罐分批发酵和两阶段补料分批发酵方式及两步加盐法研究了P(HB-HH)的高密度发酵技术参数。经55h发酵,P(HB-HH)产量可以达到17.55g/L,其中HH单体含量占共聚体的20.6%,该共聚体的分子量约为1.4×105D。结果表明S.fredii的生产性状优良,有可能通过该菌株的高密度发酵与代谢调控实现P(HB-HH)的工业化生产。更多还原

【Abstract】 The potential of a Sinorhizobium fredii strain producing a copolymer polyhydroxyalkanoate(PHA)from glucose and sodium decanoate substrates was studied in this paper.Using orthogonal design in a flask-shaker culture system,the culture medium,some culture conditions and vital regulation conditions for polymer synthesis were optimized.These optimized results were applied into further studies in two-stage fed-batch with a 10L fermentor.The whole culture process consisted of two stages,that is,the cell growth and the copolymer production.The first stage was for the cell growing to a desired biomass and the second was for the copolymer synthesis.For producing PHA polymers,the selected 8 mM sodium decanoate was added into the broth by adopting a two-step adding method for avoiding of foaming when the biomass had approached 28.5g/L dry cell.The maximum P(HB-HH)production could be 17.55 g/L with a monomer ratio of 79.4%(W/W)3-HB and 20.6%(W/W)3-HH.The molecule constitute of the copolymer is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)[P(HB-HH)] and its molecular weight(MW)is 1.4×105D.The results demonstrated that the employed S.fredii strain could be a potential candidate for industrial production of the copolymer.The fermentation parameters acquired in the experimental system offered some valuable references for studying large-scale production of the copolymer.更多还原