化学预处理对牧草酶解糖化发酵效果的影响

目的]研究化学预处理对高丹草、沙打旺、御谷和紫花苜蓿酶解糖化发酵效果的影响，评价4种牧草的能源性。方法]用不同质量分数的硫酸预处理牧草，测定处理前后纤维素、半纤维素和木质素的含量以及不同发酵时间后的葡萄糖浓度和乙醇浓度。结果]预处理后，牧草的纤维素含量上升，半纤维素和木质素的含量下降。在柠檬酸-柠檬酸钠缓冲液体系（pH=4．8）中，经1．0％（W／V）稀酸预处理后，4种牧草的乙醇提取浓度均最高。发酵过程中，葡萄糖浓度和乙醇浓度均先增加后降低，分别在发酵后24和48h达到高峰。结论]预处理促进了紫花苜蓿、高丹草、御谷、沙打旺的酶解糖化发酵，4种牧草的能源性依次降低。

Effects of Chemical Pretreatment on Enzymatic Saccharification and Fermentation of Forages

Objective] To study the effect of pretreatment with chemical substances on enzymatic saccharification of alfalfa(Medicago sativa L.),sorghum hybrid sudan grass Sorghum bicolor(L.) Moench × Sorghum sudanese(Piper) Stapf],erect milkvetch(Astragalus adsurgens Pall.) and pearl millet(Pennisetum americanum(L.) Leeke).Method] The forages were pretreated with sulfuric acid at different concentrations,and then the content of cellulose,hemicellulose,and lignin were detected and compared with that before pretreatment.The concentrations of glucose and ethanol after different fermentation time were also determined.Result] After pretreatment,the content of cellulose increased,while that of hemicellulose and lignin increased.After treatment with 1.0%(W/V) sulfuric acid,all the four kinds of forages had the highest concentration of ethanol in the citric acid-sodium citrate buffer system(pH 4.8).During fermentation process,the concentrations of glucose and ethanol first increased and then declined,peaking respectively at 24 and 48 h post fermentation.Conclusion] Pretreatment promotes the enzymatic saccharification and fermentation of alfalfa,sorghum hybrid sudan grass,pearl millet,and erect milkvetch,and their energy performance decreases in order.