利用曲霉sp.HX-1发酵稻草秸秆制备纤维素酶

以稻草秸秆原料，利用曲霉sp.HX-1固态发酵生产纤维素酶，研究了不同发酵时间、不同氮源和氮源浓度对曲霉sp.HX-1纤维素酶系的影响，并最终用硫酸铵分级沉淀和低温冷冻干燥的方法得到混合纤维素酶干品.结果表明，发酵6 d后稻草秸秆产生的纤维素酶活力单位最大，分别为CMC酶307 U/mL，C1酶841 U/mL、β-葡萄糖苷酶205 U/mL.以不同氮源优化发酵条件时发现，NH4NO3质量浓度为1 g/L时CMC酶活力达到1 652 U/mL，且失重率也到达最大值17.42%；NH4Cl质量浓度为0.5 g/L时，C1酶活力达到1 807 U/mL；尿素（UREA）质量浓度为2.0 g/L时，β-葡萄糖苷酶活力为2 033 U/mL，这表明氮源对曲霉sp.HX-1纤维素酶系的影响很大.最后在NH4NO3质量浓度为1.0 g/L的条件下，将120 g稻草秸秆发酵6 d，从发酵液中提取得到8.851 7 g混合纤维素酶的干品.此实验为以后探讨碳源或者其他因素的影响提供方法借鉴，也可以为获得纤维素酶混合酶干品的获得提供参考方法.

Production of Cellulase by Solid Fermentation of Straw Stalk Using Aspergillus sp.

This paper expounds the experiment on cellulase solid fermentation under the conditions of different fermentation days,nitrogens sources and nitrogen concentration.The experiment used the straw stalk as raw substrate,and finally obtained dry product which was high in cellulase by methods of ammonium sulfate fractionation and freeze-drying.The researches demonstrated that cellulase activity of endoglucanase,exoglucanase and β-glucosidase could reach 1652,841,205 U/mL,respectively,after 6 days’ fermentation.The optimal nitrogen sources and nitrogen concentrations to generate cellulase by Aspergillus sp.were also investigated.The results also showed that endoglucanase,exoglucanase and β-glucosidase could reach 1652 U/mL(NH4NO3 1.0 g/L),1 807 U/mL(NH4Cl 0.5 g/L),2033 U/mL(UREA 2.0 g/L),respectively.What’s more,the weight loss ratio reached 17.42% which is the maximum value under the optimal endoglucanase fermentation condition.It also demonstrated that nitrogen sources have a great impact on cellulose production.At last,8.8517 g dry product was obtained from 120 g straw fermentation broth which fermented under optimal nitrogen source(NH4NO3),nitrogen concentration(1.0 g/L) and fermentation days(6 d).