| This paper studied on the microorganisms in the Wheat Qu of shaoxin and the character of the major filamentous fungus. Three mediums, PDA, MEA, CDA, were used to seperated mould from Wheat Qu. Sixteen kinds of mould were obtained. Chromosome DNA of every kind of the pure culture was extracted by benyl chloride lysis, then the ITS rDNA fragment was amplified and sequenced. The results of identification were obtained after blastn with the GenBank database. According to the quantity of the single clones, Absidia corymbifera, Rhizopus oryzae, Rhizomucor Pusillus, Aspergillus orgyze and Aspergillus fumigatus were the major fungi in Wheat Qu.To obtain the total chromosome DNA of microbial mixture in Wheat Qu, three DNA extraction methods were applied. According to the quality, purity and integrality of DNA fragements, the benzyl chloride lysis was considered as the most effective method to extract the total chromosome DNA of microbial mixture in Wheat Qu. Funal diversity of Wheat Qu was analysed with an unclutred method RISA ( Ribosomal intergenic spacer analysis ), which based on the ITS fragement length polymorphism. ITS rDNA of microbial mixture in Wheat Qu were seperated by polyacrylmide gel electrophoresis after PCR amplification.RISA were carried out to analyze the fungal community in wheat Qu during the process of making Qu. Results showed that with increasing Qu-making the diversity of fungi in wheat Qu increased first and decreased subsequently. Gene clone libraries (ITS rDNA) containing 12 clonal sequences were successfully constructed. The fungal diversity shift observed by RISA was also shown by the clone library analysis. Consequently, the predominant fungus of wheat Qu were Absidia corymbifera, Saccharomyces cerevisiae, Rhizopus oryzae, Rhizomucor pusillus, Aspergillus oryzae, Emericella nidulans.The enzyme system of seven mold, which had been isolated from wheat Qu, was studied. Three enzymes includingα-amylase (112.5 u/g?Qu), glucoamylase (1359.4 u/g?Qu), proteinase (817.6 u/g?Qu) were produced by the Aspergillus oryzae AO-01. It could be used for starch saccharification in rice wine brewing. In addition, the effects of mixed mold culture on enzyme production were studied. The results showed that when Aspergillus oryzae AO-01 and Aspergillus niger AN-13 were incubated together, the activity of proteinase was 4.7-folds of initial activity.Box-Behnken experimental design was used to optimize the condition levels of incubation time, incubation temperature and moisture content. By response surface methodology and canonical analysis, the optimal conditions for higher production of glucoamylase were: incubation time, 32.8 h; incubation temperature, 31.2℃; moisture... |
