产二羟基丙酮的海洋菌筛选与发酵条件的优化

Screening of Dihydroxyacetone-producing Marine Bacteria and Optimization of the Fermentation Conditions

对厦门海域红树林土壤进行菌种筛选,得到20株可将甘油转化为二羟基丙酮的菌株,其中ch20-1转化率较高,达到96.3%。对该菌株进行生理生化鉴定实验和16SrDNA基因分析表明,菌株为黄杆菌属(Flavobacterium)。采用Plackett-Burman(PB)法和中心复合设计(Central Composite Design,CCD)法对该菌株进行发酵条件优化。PB实验设计与统计学分析表明:碳酸钙、山梨醇和酵母膏的浓度是影响DHA产量的三个关键因素。以DHA产量为响应目标,对三因素进行中心复合设计,并经响应面法优化分析得到了影响DHA产量的非线性模型,确定了发酵的最优培养基组成为:初始甘油浓度54.0g/L,碳酸钙浓度16.4g/L,酵母膏浓度为12.7g/L,山梨醇浓度13.1g/L。在最优条件下发酵30h,DHA产量达到52.0g/L,生产强度为1.73g/L.h-1。

20 strains capable of producing dihydroxyacetone from glycerol were isolated from the soil of the mangrove in Xiamen harbor and one of which named ch20-1 had relatively higher converting capability of 96.3%.The strain was identified by 16SrDNA sequence and systematic biochemical characteristics analysis.The results showed that the strain belongs to Flavobacterium.Plackett-Burman（PB） design and Central Composite Design（CCD） were applied to screen and optimize the fermentation conditions to produce DHA.The amount of CaCO3,and the concentrations of sorbitol and yeast extract,as three key factors,were found to significantly influence the yield of DHA PB design and the following statistic analysis.By CCD design and response surface analysis,the quadratic model for three significant factors was established with the yield of DHA as the target response.Under the optimal conditions,i.e.,30 hours of fermentation,the initial glycerol concentrations of 54g/L,16.4g/L CaCO3,12.7g/L yeast extract and 13.1g/L sorbitol,the yield of DHA were 52.0 g/L with 1.73 g/L.h-1 of production intensity.