混菌固态发酵玉米秸秆提高基质粗蛋白含量的优化培养及相关酶系活性的研究

目的]研究平菇和酵母菌混菌固态发酵玉米秸秆提高基质粗蛋白含量的优化培养条件,并探讨基质粗蛋白含量与相关酶系活性的关系。方法]以酵母种类(酿酒酵母、热带假丝酵母和产朊假丝酵母)、酵母接种量和酵母接种时间为因素设计正交试验,研究了平菇和酵母菌混菌发酵玉米秸秆提高基质粗蛋白含量的优化培养条件,同时研究了各培养条件组合下木质素酶系、滤纸酶和羧甲基纤维素酶的活性,探讨了基质粗蛋白含量与相关酶系活性的关系。结果]正交试验结果表明在A3B2C1组合培养条件下发酵基质粗蛋白含量最高,达13.36%;在此发酵条件下,培养的第5～15天漆酶和锰过氧化物酶的活性也最高,而各组合培养条件下基质滤纸酶和羧甲纤维素酶的活性则无规律可循。结论]混菌固态发酵玉米秸秆基质粗蛋白含量的优化培养条件为:在接种平菇的同时接种10%的产朊假丝酵母液体菌种。木质素酶系的活性与发酵基质的粗蛋白含量可能呈正相关关系。

Study on the Optimization of Culture Conditions for Promoting the Crude Protein Content of Fermentation Corn Straw Substrate and Activity of Relevant Enzymes under the Solid-state Fermentation with Mixed Strain

Objective] The aim was to study the optimization of culture conditions for promoting the crude protein content of fermentation corn straw substrate under the solid-state fermentation with mixed strains and discuss the relationship between crude protein content and the activity of relevant enzyme systems of the fermented corn straw substrate.Method] Different kinds of yeasts（Saccharomyces cerevisiae,Candida tropicalis and Candida utilis）,inoculation volume of yeast（5%,10% and 20%） and inoculation time were used as factors to make orthogonal experiment.The optimization of culture conditions for promoting the crude protein content of fermentation corn straw substrate under the solid-state fermentation with Pleurotus ostreatus and yeasts were studied.Meanwhile,the activities of ligninolytic enzymes,filter paper enzyme and carboxymethyl cellulose under different culture conditions were studied.The relationship between the between crude protein content and the activity of relevant enzyme systems of the fermented corn straw substrate was discussed.Result] The results of the orthogonal experiment showed that the crude protein content of fermentation substrate was highest（13.36%）under A3B2C1 combination culture conditions.Under these fermentation conditions,the activities of laccase and manganese peroxidase of the fermentation substrate were also highest during the 5th-15th day.But activities of filter paper enzyme and carboxymethyl cellulose under different combination culture conditions had no obvious difference.Conclusion] The optimal culture conditions for promoting the crude protein content of fermentation corn straw substrate under the solid-state fermentation was as follows：inoculating 10% liquid strain producing C.utilist at the same time of inoculating P.ostreatus.The activity of ligninolytic enzyme system might have a positive correlation with crude protein content of the fermented corn straw substrate.