蝉拟青霉液体发酵条件优化

采用液体发酵蝉拟青霉,对蝉拟青霉的发酵条件进行优化,以提高蝉拟青霉胞外多糖产量及生物量。摇瓶发酵条件下,在单因素基础上设计正交实验确定各因素的最佳组合。优化后得最佳发酵培养基:蔗糖8%,牛肉膏0.75%,酵母膏0.125%,MgSO_4·7H_2O 0.3%,KH_2PO_4 0.2%,麸皮0.5%。该条件下胞外多糖产量为5.96 g/L,生物量为42 g/L,较优化前提高了1倍。采用发酵罐进行扩大培养,对分批发酵时的初糖浓度进行了优化,并分析了补料分批发酵对发酵过程的影响。发酵罐培养时最适初糖浓度为5%,此时生物量最高为38 g/L,多糖含量最高为5.5 g/L;采用补料分批发酵时,多糖产量最高为5.89 g/L,生物量最高为40 g/L,效果优于分批发酵。

Optimization of Liquid Fermentation Condition of Paecilomyces cicadae

In order to improve biomass and the production of extracellular polysaccharide from Paecilomyces cicadae,liquid fermentation was adopted, and the fermentation conditions of P. cicadae were optimized. Under the conditions of shaker flask fermentation, orthogonal experiment was designed based on single factor to determine the best combination of each factor. The optimum fermentation medium: sucrose 8%, beef extract 0.75%, yeast extract 0.125%, MgSO₄·7H₂O 0.3%, KH₂PO₄ 0.2%, bran 0.5% was obtained after the optimization. Under these conditions, the highest yield of extracellular polysaccharide was 5.96 g/L, and the biomass was at 42 g/L, doubled than before the optimization. Afterwards, the fermentation tank was used for the expansion culture of P. cicadae, and the initial sugar concentration was optimized, and the effect of fed batch fermentation on the fermentation process was analyzed. The most suitable initial sugar concentration of fermenter culture was 5%, the highest biomass at the moment was 38 g/L and the highest extracellular polysaccharide content was 5.5 g/L under the condition. When adopting fed batch fermentation, the highest polysaccharide yield was 5.89 g/L, the highest biomass was 40 g/L, and the effect was better than batch fermentation.