Ethanolic fermentation of hydrolysates from ammonia fiber expansion (AFEX) treated corn stover and distillers grain without detoxification and external nutrient supplementation
Ethanolic fermentation of hydrolysates from ammonia fiber expansion (AFEX) treated corn stover and distillers grain without detoxification and external nutrient supplementation
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DOI：
10.1002/bit.21609
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发表时间：
2008-02-15
影响因子：
3.8
通讯作者：
Balan, Venkatesh
中科院分区：
文献类型：
--
作者：
Lau, Ming W.;Dale, Bruce E.;Balan, Venkatesh
外部营养补充和水解物解毒显着增加了纤维素乙醇的生产成本。在本研究中，我们研究了在低初始细胞密度（16 mg 干重/L）下使用产乙醇菌大肠杆菌 KO11 和适应菌株 ML01 在不清洗、解毒或外部营养补充的情况下发酵纤维素水解产物的可行性。纤维素水解产物源自酶消化氨纤维膨胀 (AFEX) 处理的玉米秸秆和干酒糟和可溶物 (DDGS) 在高通过对来自 AFEX 处理的玉米秸秆的水解产物进行 KO II 的选择性进化来实现适应，无论菌株如何，代谢乙醇产量都接近理论极限（0.51 克乙醇/克消耗的糖）。 DDGS 提高了玉米秸秆水解产物的发酵能力，然而，在这些实验条件下，发酵过程中的酶水解和木糖利用是玉米秸秆生产乙醇的瓶颈。 总之，在发酵中利用 DDGS 等营养丰富的原料可以替代昂贵的培养基补充。
External nutrient supplementation and detoxification of hydrolysate significantly increase the production cost of cellulosic ethanol. In this study, we investigated the feasibility of fermenting cellulosic hydrolysates without washing, detoxification or external nutrient supplementation using ethanologens Escherichia coli KO11 and the adapted strain ML01 at low initial cell density (16 mg dry weight/L. The cellulosic hydrolysates were derived from enzymatically digested ammonia fiber expansion (AFEX)-treated corn stover and dry distiller's grain and solubles (DDGS) at high solids loading (18% by weight). The adaptation was achieved through selective evolution of KO I I on hydrolysate from AFEX-treated corn stover. All cellulosic hydrolysates tested (36-52 g/L glucose) were fermentable. Regardless of strains, metabolic ethanol yields were near the theoretical limit (0.51 g ethanol/g consumed sugar). Volumetric ethanol productivity of 1.2 g/h/L was achieved in fermentation on DDGS hydrolysate and DDGS improved the fermentability of hydrolysate from corn stover. However, enzymatic hydrolysis and xylose utilization during fermentation were the bottlenecks for ethanol production from corn stover at these experimental conditions. In conclusion, fermentation under the baseline conditions was feasible. Utilization of nutrient-rich feedstocks such as DDGS in fermentation can replace expensive media supplementation.