醋酸菌发酵产细菌纤维素的过程优化

汉逊氏葡糖酸醋杆菌(Gluconacetobacter hansenii)利用传统Hestrin-Scharmm (HS)培养基发酵生产细菌纤维素(bacterial cellulose,BC)的过程中,普遍存在着BC产量不高、葡萄糖利用率低等问题。本研究首先比较了传统HS培养基和改良HS培养基发酵生产BC的结果,改良HS培养基中BC干重产量达到3.34g/L,较传统HS培养基提高了28%,但培养基废液中仍含有41%和70%的残糖和残氮;继而对改良HS培养基一次发酵废液进行优化,添加2.5 g/L酵母粉和1.8 g/L磷酸氢二钠,调节p H至5.9进行二次发酵,可获得3.16 g/L的BC干重,同时发酵液中副产物乙酸浓度仅为一次发酵的一半。综上,利用改良HS培养基发酵结合优化发酵废液进行二次发酵,共获得6.50 g/L的BC干重,是优化前的2.5倍以上,并且葡萄糖的利用率和转化率也分别由56.74%,22.86%提高至88.02%,36.87%。

Fermentation Process Optimization of Bacterial Cellulose via Acetic Acid Bacteria

In the production of bacterial cellulose (BC) by Gluconacetobacter hansenii via traditional Hestrin-Scharmm (HS) medium, there are still some problems that limit the production, such as low BC production and utilization rate of glucose. In this study, the results of BC production by fermentation of traditional HS medium and improved HS medium were first compared and the BC yield by improved HS medium was increased by 28% to 3.34 g/L. However, the fermentation waste still contained 41% residual sugar and 70% residual nitrogen. Afterwards, the primary fermentation waste was optimized and used for secondary fermentation. In consequence, 3.16 g/L of BC could be produced by adjusting the pH of fermentation waste to 5.9 and adding 2.5 g/L yeast extract and 1.8 g/L Na2HPO4, and the concentration of acetic acid was only half of that in primary fermentation. In conclusion, the yield of BC achieved 6.50 g/L, which was 2.5 times as much as before. Moreover, the utilization rate and conversion rate of glucose were increased from 56.74% to 88.02% and 22.86% to 36.87%, respectively.