利用微生物混合培养技术生产聚羟基烷酸(PHA)研究

Production of Polyhydroxyalkanoates by a Mixed Culture

研究了圆褐固氮菌 (Azotobacterchroococcum)突变株G 3与巨大芽孢杆菌 (Bacillusmega terium)G 6发酵生产聚羟基烷酸 (PHA)的人工可配伍性 ,确定了它们混合培养的适宜条件 ,先将G 3菌株发酵培养 2 4～ 2 8h后 ,再以 1 5 % (v v)接种量接入G 6菌株并同时补加 0 5 % (g g)蛋白胨 (FP)和 0 5 % (g g)NH4 NO3,继续混合培养 42～ 46h ,细胞干重达 32g L ,PHA含量为80 % ,再结合补料技术最终生物量可达 5 3g L ,PHA产生量达 42 4g L。糖对PHA的转化率为0 32。人工混合培养成功地解决了固氮菌发酵生产PHA过程中 ,发酵液粘度过高 ,传质较差 ,补糖总量上不去等技术问题。

The feasibility of using a mixed culture of A.chroococcum G-3 and B.megaterium G-6 in the production of polyhydroxyalkanoates has been studied. The optimal conditions for the mixed culture were established. After the G-3 strain was incubated alone for 24～28 hours, the broth was inoculated with 15% (v/v) of the G-6 culture. 0.5% peptone and 0.5% NH_4NO_3 were added to the mixture. The mixed culture was proceed to 42～46 h. Final dry cell weight was up to 32 g/L and the content of PHA was up to 80%. Combined with the nutrient supplement, the dry cell weight increased to 53 g/L and the content of PHA increased to 42g/L. The conversion of sucrose to PHA is 0.32.The mixed culture solved the problems caused by the increase in viscosity, poor mass transfer, low supplemental sucrose amounts.