不同流加策略对内生真菌拟茎点霉生产去乙酰真菌环氧乙酯的影响

Abstract

去乙酰真菌环氧乙酯是红树林内生真菌拟茎点霉(PHOMOPSISSP.)的次级代谢产物,为罕见的去乙酰真菌环氧二烯类化合物,结构十分新颖,具有较好的抗肿瘤活性.本实验以诱变后获得的拟茎点霉A818为出发菌株,采用发酵罐对拟茎点霉A818进行培养,考察了不同发酵策略对去乙酰真菌环氧乙酯积累的影响,获得了适合去乙酰真菌环氧乙酯发酵生产的流加策略.与间歇培养相比,分别流加麦芽糖和马铃薯煮汁均能显著提高去乙酰真菌环氧乙酯的积累量,而且将糖质量浓度控制在30--40 g/l利于去乙酰真菌环氧乙酯的积累.实验最终确定的发酵策略为:前期恒速流加马铃薯煮汁同时变速流加麦芽糖,并控制糖质量浓度在30--40 g/l的联合流加方式.采用该发酵策略对拟茎点霉A818进行发酵,最终去乙酰真菌环氧乙酯质量浓度达到184.0 Mg/l,为间歇发酵的4.64倍.

Deacetylmycoepoxydiene(DAM) is a secondary metabolite derived from a mangrove endophytic fungus phomopsis sp..It would become a new type of antitumor agent because of its novel structure and remarkable antitumor activity.In this work,a mutant strain-Phomopsis sp.A818 was employed to produce DAM.In order to evaluate the influence of different feeding modes on DAM production,batch and fed-batch cultivations of Phomopsis sp.A818 were performed in a conventional stirred bioreactor.Compared with batch fermentation,DAM production was significantly improved by feeding potato steep liquor and maltose with a constant feeding rate,respectively.DAM production was increased in fed-batch cultivation by maintaining a constant maltose concentration of 30 g/L to 40 g/L.Finally,the feeding mode that maintaining a constant maltose concentration(30 g/L to 40 g/L) and feeding potato steep liquor at a constant rate during fermentation was selected as the optimized feeding strategy.By using it,a high DAM yield of 184.0 mg/L was achieved,which was approximately 4.64 times of which obtained in batch fermentation.