Papers by Keyword: Luzhou-Flavor DaQu

Abstract: Six moulds were isolated from Luzhou-flavor Daqu through traditional microorganism isolation method. Among them, two strains njsys-3 and njsys-6 have shown higher glucoamylase activity, their enzyme activity were 1842 U/g and 2349U/g separately. Molecular biological identification results shown that strain njsys-3 was Aspergillus clavatus and strain njsys-6 was Aspergillus niger. Daqu-making test showed that once the inoculating amount of seeding broth of njsys-3 attached to 6 ‰, the glucoamylase activity of Daqu can increase 26.9%; when the inoculating amount of seeding broth of njsys-6 attached to 6 ‰, the activity of glucoamylase of Daqu can increase 34.1% and the fragrance of Daqu can increase.

Abstract: The metabolites characteristics of a bacteria producing esterifying synthetase in different fermentation conditions were studied. A bacteria strain producing esterifying enzyme was isolated from Luzhou-flavor Daqu and it was identified by Biolog Microbes automated identification System. Fermentation conditions such as fermentation time, fermentation initial pH and fermentation temperature were changed. The fermentatiom broth was extracted by ethanol and analyzed by GC-MS. The results showed that the strain was Geobacillus thermoglucosidasius. With the prolonging of fermentation time, methanol and various higher alcohols were gradually decreased and even disappeared, but the esters were gradually increased. With the rise of fermentation initial pH, the acids were decreased. When initial pH was 7.5, more esters were produced, but some metabolites were not changed with the initial pH of fermentation, such as acetic acid, acetaldehyde, 3-methyl butanol and 3-Hydroxy-2-butanone etc. With the increase of fermentation temperature, the alcohols and acids kinds increased. When the fermentation temperature was 35°C, the more esters were produced.

Abstract: A Rhizopus strain producing esterifying enzyme was isolated from Luzhou-flavor DaQu. It was preliminary identified as Rhizopus arrhizus. Through the research of the culture conditions of the strain producing esterifying enzyme, it was found that the enzyme activity could reach 7.91U/mL as 2% corn meal used as C source, 6% peptone used as N source, initial pH value was 6.0, and 72h culture with 150 r/min agitation at 30°C.

Abstract: The metabolies characterization of mold producing esterifying synthetase of different culture conditions were studied. A mold strain producing esterifying enzyme was isolated from Luzhou-flavor DaQu and it was identified by Biolog Microbes automated identification System. Culture conditions such as culture temperature, fermentation time and carbon source were changed. The fermentatiom broth was extracted by ethanol and analyzed by GC-MS. The results showed that the strain was Aspergillus flavus. When the culture temperature increased, the molecular weight of its metabolites increased, the synthesis of high alcohol increased too, and their carbon chain lengthened gradually. When incubation time was prolonged, the varying law of the synthesis of its metabolites was alcohols-acid-ester, the metabolites with longer carbon chain produced earlier than the metabolites with shorter carbon chain. When the carbon source were starch, sucrose and bran, n-butyl alcohol and isoamyl alcohol were the common metabolites. When the carbon source was sucrose, most of the metabolites were alcohol and acid with shorter carbon chain. When the carbon source was starch, diethyl succinate was produced. When the carbon source was bran, the metabolites were less.