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

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%, MgSO₄ was 1.9%, Na₂HPO₄ 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.