关键词： 曲霉sp.HX-1, 稻草秸秆, 纤维素酶, 氮源, 硫酸铵分级沉淀, 低温冷冻干燥

Abstract: 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).

Key words: aspergillus sp.HX-1, straw stalk, cellulase, nitrogen sources, ammonium sulfate fractionation, freeze-drying