高温纤维素分解菌筛选及JSU-5产纤维素酶特性研究

目的]为产纤维素酶菌株的选育和产酶研究提供参考依据。方法]从牛粪和麦秸秆堆肥中筛选出高温纤维素分解菌,对其产纤维素酶的条件：碳源、氮源、pH值、NaCl浓度、装液量等进行研究,并用正交试验确定最佳发酵条件。结果]从筛选出的分解纤维素的11株高温菌种中选出产酶活性较高的JSU-5。其高温产酶条件优化结果表明,当pH值在6左右时,产酶活性最高;培养时间为5 d时,产酶活性最高;以麦草为碳源,产酶活性最高;以黄豆饼粉为氮源,产酶活性最高;较为适合的钠盐浓度为0.2%。培养基组分中影响纤维素酶活性的主要因素为碳源、水分和氮源。结论]菌株JSU-5产纤维素酶培养基的最佳营养组成为麦草装量50 g/L,黄豆饼粉30 g/L,NaCl2 g/L,装液量60 ml,pH值为6.0,发酵温度为50℃。该条件下所产酶活力为113.4 U/ml。

Research on the Screening of Bacteria Decomposing High-temperature Cellulose and the Characteristics of JSU-5 Producing Cellulase

Objective] The reference for the bacteria strain producing cellulase enzyme and its efficiency was provided.Method] The bacteria decomposing hightemperature cellulose was screened out from cow dung and wheat straw compost.The condition of cellulase production such as carbon,nitrogen,pH value,NaCl concent-ration,the volume of liquid and so on was researched and the optimum fermentation condition was determined with orthogonal test.Results] The bacteria strain——JSU-5,selected from 11 high-temperature bacteria of cellulose decomposition,had the highest enzyme activity.The result indicated there was the highest activity of enzyme production when the pH value was at around 6 or when the culture time was for 5 d.And also there was the highest activity of enzyme production when the wheat straw was used as carbon source,or the soybean powder was used as nitrogen source.The concentration of sodium was 0.2%.The main factor affecting the cellulose enzyme activity in medium components was carbon,water and nitrogen.Conclusion] The best nutrition component in medium for strains——JSU-5 producing cellulase was the quantity of wheat straw,50 g/L;soybean flour,30 g/L;NaCl,2 g/L;the volume of liquid,60 ml;pH value,6.0 and the fermentation temperature,50 ℃,under which,113.4U/ml of enzyme was produced.