外源有机酸对红树林内生真菌发酵生产1403C的影响

Influence of exogenous organic acid on 1403C production by submerged culture of mangrove endophytic fungi HaloroselUnia sp.

本文主要研究了外源有机酸对红树林内生真菌No.1403发酵生产1403C的影响,并且分别在摇瓶和5 L反应器进行柠檬酸(钠)的间歇性补加实验。研究发现在新培养基条件下添加丙二酸前体对1403C产量无促进作用。摇瓶发酵前期添加的柠檬酸对1403C合成代谢有轻微抑制效应,中后期补加的柠檬酸很可能被用于维持菌体的初级代谢。而反应器发酵的1403C产量比对照产量提高8.6%,达到0.81 g/L;碳饥饿时期,在pH<7.0且菌体稳定存在条件下,添加外源柠檬酸可促进1403C的合成。

In this study, intermittent organic-acid-fed-batch fermentation of mangrove endophytic fungi Halorosellinia sp. （No. 1403 ） was performed in shake flask and 5 L bioreactor to discover the influence of exogenous organic acid on 1403C production. The results showed that it was unfavorable to feeding malonic acid, the precursor of product biosynthesis, any- time under optimized medium culture in this case, which was opposite to the former report. Citric acid did slight harm to 1403C production via shake flask culture. It was probable that citric acid was used for maintaining the primary metabolism during the stationary phase. Moreover, 1403C production of citrate-fed-batch fermentation in 5 L bioreactor reached 0.81 g/L, which was 8.6% higher than that of the control. When carbon starvation occurred, accompanied with healthy mycelium and pH 〈7.0, it was beneficial for 1403C biosynthesis by feeding exogenous citric acid.