| The maotai-luzhou-flavor liquor is one of innovative liquor types in China, which has been universally popular for its technology characteristics combined with multifold-flavor liquors and maotai-luzhou flavor. Daqu plays an unparalleled role in the production process of maotai-luzhou-flavor liquor in china, due to the unique features of traditional fermentation technology and the limitation of research methods in this field, the knowledge of microbes community structure occurred in high temperature Daqu is still imperfect. In this experiment, the 9 samples, which were collected from the various stages of high temperature Daqu fermentative process manufactured by Baiyunbian Co. Ltd, were used as the tested subject. The main research use physicochemical analysis technology and high-throughput sequencing technology to study the change law of physicochemical indexes and the microflora multiplicity of the Baiyunbian high temperature Daqu in the fermentative process. The results were showed as follows:The physicochemical indexes results show the temperature got a rapid rise at first and reached top temperature at 62.3℃, after then lowered continuously to near room temperature during the whole fermentative process of Daqu; Total acid, reducing sugar rised at first and lowered later, both of them begun to recover at the later time; During the cultivate period of Daqu, saccharifying and liquefaction power had a biggest drop in and kept a low level until they got to the storage period, both of them recovered continuously, at last, they were 158 u /g and 1.2 u/g in matured Daqu, respectively.The culture-dependent analysis results show the bacterial population got a rapid drop firstly and continued to rise, it reached highest value 2.73×106 CFU/g on day 50, and lowered when it got to the storage period; The population of spore rised when cultivate period begun, its change trend consistent with bacteria from day 14; In the fermentative process of Daqu, the proportion of bacteria in spore status played a trend like this: Firstly rised, and fell later, at last it continued to rise and reached 69.1% on day 140; In the cultivate period, the mold was few, but when it got to the storage period, its population rising rapidly and reached 2.83×105 CFU/g on day 140; The yeast was rare to discover in samples.11 different microbial species were selected according to plate screening, there were 3 bacteria strains: Bacillus amyloliquefaciens, Bacillus methylotrophicus, Bacillus licheniformis, all of them were Bacillus sp; 1 yeast strain: Saccharomycopsis fibuligera; 7 mold strains: Beauveria bassiana, Eurotium athecium, Eurotium amstelodami, Aspergillus versicolor, Thermoascus crustaceus, Mycocladus corymbiferus, Paecilomyces variotii.The 16 S rDNA amplicon sequencing results of bacterial community show when it got to the cultivate period, the quantity of OTUs in Daqu samples was rapidly dropped and quickly rised, after then there were another drop and rise, and its constantly dropped in storage period. 117 OTUs were obtained from all samples. The main bacterial phylums were Firmicutes and Actinobacteria; The main bacterial familys were Bacillaceae, Thermoactinomycetaceae, Pseudonocardiaceae and Lactobacillaceae. The main bacterial genera were Saccharopolyspora, Thermoactinomyces, Unclassified Thermoactinomyce-taceae and Lactobacillus; The bacterial community composition of the adjacent time samples was similar.The ITS amplicon sequencing results of fungal community show in the whole fermentative process, the quantity of OTUs in Daqu samples was played a trend like this: Firstly its dropped and rised later, after then there were another drop and rise; 82 OTUs were obtained from all samples. The main fungal phylum was Ascomycota. The main fungal familys were Unclassified Eurotiales, Trichocomaceae and Cryptococcaceae. The main fungal genera were Thermomyces, Aspergillus and Candida; The fungal community composition of the adjacent time samples was similar. |
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