Bio-energy Research Center, Chonnam National University, Gwangju 500-757, Republic of Korea.
Biotechnol Biofuels. 2013 Nov 29;6(1):166. doi: 10.1186/1754-6834-6-166.
Rice straw has considerable potential as a raw material for bioethanol production. Popping pretreatment of rice straw prior to downstream enzymatic hydrolysis and fermentation was found to increase cellulose to glucose conversion efficiency. The aim of this study was to investigate the influence of popping pretreatment and determine the optimal enzyme loading using a surface response design.
The optimal doses of cellulase and xylanase enzymes were 23 FPU and 62 IU/g biomass, respectively. Using the optimized enzyme condition and popping pretreatment of rice straw (15% substrate loading, w/v), a sugar recovery of 0.567 g/g biomass (glucose; 0.394 g/g) was obtained in 48 h, which was significantly higher than that from untreated rice straw (total sugar recovery; 0.270 g/g biomass). Fermentation of the hydrolyzates by Saccharomyces cerevisiae resulted in 0.172 g ethanol/g biomass after 24 h, equivalent to 80.9% of the maximum theoretical yield (based on the amount of glucose in raw material). Changes in the chemical composition and surface area of rice straw were also investigated before and after popping pretreatment. The results showed little or no difference in chemical composition between the pretreated rice straw and the control. However, the surface area of pretreated rice straw increased twofold compared to the control.
Popping pretreatment of rice straw can effectively improve downstream saccharification and fermentation, important for bioethanol production.
稻草作为生物乙醇生产的原料具有相当大的潜力。研究发现，对稻草进行爆裂预处理，然后进行下游的酶解和发酵，可以提高纤维素转化为葡萄糖的效率。本研究旨在探讨爆裂预处理的影响，并使用表面响应设计确定最佳酶用量。
纤维素酶和木聚糖酶的最佳酶用量分别为 23 FPU 和 62 IU/g 生物质。使用优化的酶条件和稻草爆裂预处理（底物负载量为 15%，w/v），在 48 小时内获得了 0.567 g/g 生物质的糖回收率（葡萄糖为 0.394 g/g），明显高于未处理稻草的糖回收率（总糖回收率为 0.270 g/g 生物质）。将水解物通过酿酒酵母发酵 24 小时后，可获得 0.172 g 乙醇/g 生物质，相当于原料中葡萄糖最大理论产量的 80.9%（基于原料中葡萄糖的量）。还研究了爆裂预处理前后稻草的化学成分和表面积的变化。结果表明，预处理后的稻草与对照稻草在化学成分上几乎没有差异，但预处理后的稻草表面积比对照增加了一倍。
稻草的爆裂预处理可以有效地改善下游的糖化和发酵，这对生物乙醇生产很重要。
