木葡糖醋杆菌发酵产细菌纤维素的培养基优化及外源物质对其代谢的影响

Optimization of Fermentation Medium of Bacterial Cellulose Production by Gluconacetobacter and Effects of Exogenous Substances on Its Metabolism

为了提高细菌纤维素(Bacterial Cellulose,BC)的产量,采用响应面法优化了木葡糖醋杆菌(Gluconaceto-bacterxylinus)的发酵培养基,基于优化结果探究了海藻酸钠(SA)、羧甲基纤维素钠(CMC-Na)、羧甲基纤维素(CMC)三种外源物质对BC合成过程中BC产量、总糖消耗、乙酸、丙酮酸等的影响。结果表明,最优培养基成分为葡萄糖4%、酵母浸粉1%、蛋白胨0.8%、MgSO_(4)1.9%、Na_(2)HPO_(4)0.2%、乙酸0.4%、乙醇1.6%,BC产量为5.19 g/L。外源添加SA、CMC-Na、CMC后,总糖的消耗量分别提高了29.9%、22.82%和15.73%,BC终产量分别为6.72、6.01和5.1 g/L。相较于对照组,SA和CMC-Na组丙酮酸含量的增幅分别为29.02%和16.52%,促进了丙酮酸的积累与利用,提高了BC的积累量。CMC添加组乙酸的积累量最高为4.27 g/L,这与BC产量的下降有一定关系。

In order to improve the yield of bacterial cellulose(BC),the fermentation medium of the Gluconacetobacter xylinus was optimized by response surface methodology.Based on the optimization results,the effects of sodium alginate(SA),sodium carboxymethyl cellulose(CMC-Na)and carboxymethyl cellulose(CMC)on the yield of BC,total sugar consumption,acetic acid and pyruvic acid were investigated.The results showed that when the amounts of addition of glucose was 4%,yeast extract powder was 1%,peptone was 0.8%,MgSO_(4) was 1.9%,Na_(2)HPO_(4) was 0.2%,acetic acid was 0.4%,ethanol was 1.6%,the actual yield of BC could reach 5.19 g/L.After adding SA,CMC-Na and CMC,the total sugar consumption increased by 29.9%,22.82%and 15.73%,and the yield of BC was 6.72,6.01 and 5.1 g/L,respectively.The content of pyruvic acid in SA group and CMC-Na group was increased by 29.02%and 16.52%compared with the control group.SA and CMC-Na promoted the accumulation and utilization of pyruvate acid,the yield of BC accumulation was increased.The highest acetic acid accumulation(4.27 g/L)was observed in the CMC addition group,which had a certain relationship to the lower yield of BC than the control group.