高效降解纤维素菌系的筛选分离及复合菌系的构建

为了从土壤及腐烂的秸秆中筛选一组高效降解纤维素的复合菌系，并研究其在天然纤维素中的应用。通过采用刚果红染色液法对分离的菌株初步筛选，利用DNS法测定纤维素酶活力。选取无拮抗高效降解纤维素菌株进行组合培养构建降解纤维素复合菌系。结果表明，3株真菌混合培养后酶活力效果优于单一菌株。经过形态学和分子生物学鉴定，真菌F1为葡萄座腔菌(Botryosphaeria)、F2为米根霉(Rhizopus oryzae)及F5为尖孢镰刀菌(Fusarium oxysporum)。复合培养后，在碳源为秸秆时，单菌株酶活值分别为F1 39.2 μmol/mL，F2 31.4 μmol/mL，F5 40.6 μmol/mL，真菌组合F1+F2+F5培养后酶活值为50.12 μmol/mL，复合真菌系酶活值比F5单菌株提高了23%。通过实验研究得出复合菌系对纤维素的降解效果优于单一菌株，菌株F1、F2和F5具有潜在的开发价值。

Screening of Straw Cellulose Degrading Microorganisms and Construction of A High Efficient Complex Microbial System

This article aims to screen an efficient cellulolytic mixed strain from the soil and rotten stalk, and study its application to natural cellulose. Congo red stain was used to primarily screen the isolated strains, and DNS method was used to measure all strains＇ CMC enzyme activity. A complex microbial system capable of degrading cellulose with high efficiency was constructed by mixed cultured of strains of high enzyme activity and no antagonism. The results showed that, the enzyme activity of 3 fungus mixed culture was higher than that from the fermentation of single fungus. Strain F1 was identified as Botryosphaeria, F2 was identified as Rhizopus oryzae and F5 was identified as Fusarium oxysporum by morphological and molecular technology.When the carbon source was straw, the CMC enzyme activity of F1, F2, F5 was 39.2 μmol/mL, 31.4 μmol/mL,40.6 μmol/mL respectively. The cellulase produced by mixed fermentation of F1＋F2＋F5 showed a strong enzyme activity of 50.12 μmol/mL. The enzyme activity of fungus community was 23% higher than that of F5 single fungus. The experiment results indicated that the enzyme activity of the microbial community was higher than that from the fermentation of single fungus, and fungus F1, F2 and F5 had tremendous potential value for microbial fertilizer.