细菌发酵生产聚羟基烷酸的摇瓶条件优化

Optimization of Polyhydroxyalkanoates Shake Flask Fermentation Condition

为选育能利用廉价碳源并且高产聚羟基烷酸的优良菌株,对分离自活性污泥中的菌株Zoogloeasp.GY3进行了摇瓶发酵条件的优化试验。结果表明,其最佳发酵条件为:初始蔗糖浓度3%,摇瓶种子接种量10%,接种种龄18 h,在此条件下发酵32 h后,PHAs的含量可以达到84.1%。此外,在以自来水为溶剂的条件下,菌株GY3对微量元素无特殊要求,因而降低了发酵成本。

It is one of most important factors that screening excellent strains that could use cheap carbon sources and accumulate polyhydroxyalkanoates fruitfully,to produce biodegradable plastic for industrial utilization.Shake flask fermentation conditions of Zoogloea sp.GY3 that was isolated from activated sludge were optimized.Zoogloea sp.GY3 was rod with size of(0.5~1.0)×(1.0~3.0)μm,had polar flagellum,produced 3~5 small and roundish PHAs granules through transmission electron microscope under 12 h.After fermentation,the microorganism became larger and anomalistic shape and PHAs granules were full of cell.Initial sucrose concentration had some influence on microorganism growth and PHAs accumulation.The best initial sucrose concentration was 3% and the sucrose consumption rate was 70%,below or over this level having negative effect.Furthermore,the best inoculation rate of shaking flask was 10% and seeding age was 18 h.PHAs concentration could reach 84.1% after 32 h of total fermentation time.Using L_(18)(3)^(7)orthogonal layout,the influences of trace elements B^(3+),Ca^(2+),Zn^(2+),Mn^(2+),Mo^(6+),Ni^(2+)and Cu^(2+)were tested.The results showed that the trace elements were not necessary for strain GY3 when used tap water as solvent,and this reduced the production cost.