为探究以原位酶解方式整合产酶菌株的发酵条件和酶解条件差异的可行性,以木质纤维结构典型的水稻秸秆为对象,里氏木霉为产酶微生物,通过研究液态发酵原位酶解糖化水稻秸秆,对发酵过程和酶解过程协同控制条件进行优化。结果显示,最优产酶发酵条件为水稻秸秆添加量 30 g/L,发酵温度30 ℃,初始pH 6.5,发酵时间48 h;最优酶解条件为酶解pH 4.8,酶解温度50 ℃,酶解时间24 h,最终的秸秆比产糖量为0.350 g/g。通过在酶解阶段时补加少量的粗酶液(体积分数5%),可以提升最终的比产糖量,由0.332 g/g提升至0.400 g/g,约提升了20%。原位酶解糖化秸秆纤维素是实现水稻秸秆高效降解利用的可行方式。该研究可为纤维素酶解工艺提供技术参考,为秸秆纤维素资源化利用提供一定理论依据。
To explore the feasibility of integrating the fermentation conditions and enzymatic hydrolysis conditions of enzyme producing strains by in situ enzymatic hydrolysis, the rice straw with typical lignocellulosic structure was used as the substrate and Trichoderma reesei was used as the enzyme producing microorganism. By analysis of the in situ enzymatic hydrolysis of rice straw after T. reesei fermentation, the synergistic control conditions of fermentation and enzymatic hydrolysis were optimized. The optimal fermentation conditions were as follows: the addition amount of rice straw 30 g/L, 30 ℃, initial pH 6.5, fermentation time 48 h. The enzymolysis conditions were pH 4.8, 50 ℃, enzymolysis time 24 h. The final straw specific yield of sugar was 0.350 g/g. By adding small amount of crude enzyme solution (5%) in the enzymatic hydrolysis stage, the final straw specific yield of sugar increased from 0.332 g/g to 0.400 g/g, increased by 20%. The results showed that in situ enzymatic hydrolysis and saccharification of straw cellulose was capable of achieving efficient degradation and utilization of rice straw. This study provides technical example for cellulase hydrolysis and certain theoretical basis for resource utilization of straw cellulose.
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