丙酮丁醇梭菌发酵菊芋汁生产丁醇

Butanol production from hydrolysate of Jerusalem artichoke juice by Clostridium acetobutylicum L7

摘要:

对丙酮丁醇梭菌Clostridium acetobutylicum L7发酵菊芋汁酸水解液生产丁醇进行了初步研究。实验结果表明，以该水解液为底物生产丁醇，不需要添加氮源和生长因子。当水解液初始糖浓度为48.36 g/L时，其发酵性能与以果糖为碳源的对照组基本相同，发酵终点丁醇浓度为8.67 g/L，丁醇、丙酮和乙醇的比例为0.58∶0.36∶0.06，但与以葡萄糖为碳源的对照组相比，发酵时间明显延长，表明该菌株葡萄糖转运能力强于果糖。当水解液初始糖浓度提高到62.87 g/L时，发酵终点残糖浓度从3.09 g/L增加到3.26 g/L，但丁醇浓度却提高到11.21 g/L，丁醇、丙酮和乙醇的比例相应为0.64∶0.29∶0.05，表明适量糖过剩有助于C. acetobutylicum L7胞内代谢从丙酮合成向丁醇合成途径调节；继续提高水解液初始糖浓度，发酵终点残糖浓度迅速升高，丁醇生产的技术经济指标受到明显影响。

Abstract:

Butanol production from acid hydrolysate of Jerusalem artichoke juice by Clostridium acetobutylicum L7 was investigated, and it was found that natural components of the hydrolysate were suitable for solvent production with the species. With batch fermentation using the medium containing 48.36 g/L total sugars, 8.67 g/L butanol was produced at 60 h, and the ratio of butanol to acetone to ethanol was 0.58:0.36:0.06, which were similar to the fermentation with fructose as carbon source, but both of these two fermentations were slower than that with glucose as carbon source, indicating the fructose transport of the species might not be effective as that for glucose. When the total sugars of the medium were increased to 62.87 g/L, the residual sugars increased slightly from 3.09 g/L to 3.26 g/L, but butanol production of the fermentation system was improved significantly, with 11.21 g/L butanol produced and the ratio of butanol to acetone to ethanol at 0.64:0.29:0.05, which illustrated that an excess in sugars enhanced the butanol biosynthesis of the species by compromising its acetone production. When the sugar concentration of the medium was further increased, much more sugars were remained unconsumed, making the process economically unfavourable.