The Breeding And Application Of Killer Yeasts In Xiaoqu-making With Low-carbon Model

This paper used the Saccharomyces cerevisae1445and antibacterial bacillus subtilisas the parent strain, by the protoplast fusion technology selected one strain which has thebacteriostatic action, and identified this strain belonged to Sacchromyces cerevisiae andnamed it killer yeast Sa2. Firsyly I studied the killer yeast Sa2antibacterial characteristicsand researched the strain’s growth and fermentation condition. Secondly I explored the keytechnical parameters of Xiaoqu-making with low-carbon model.Finally I studied thefermentation condition by using long-shaped rice as raw material and xiaoqu assaccharifying leaven. The research contents and results were listed as follows:(1)According to protoplast fusion method we fused Sacchromyces cerevisae1445andbacillus subtillus together then selected a fusion strain based on the physiological andbiochemical characteristics as well as the18SrDNA sequence analysis identified assacchromyces cerevisae. named it killer yeast Sa2. The antibacterial action of the strainwas studied by the method of paper-disc. The result display the killer yeast Sa2have agood inhibitory effect to E. coli and other bran bacteria A、B、C、D, less effect observed formold but have a good inhibition to mold spores.(2) According to studies of the growth and fermentation characteristics we confirmedthat the killer yeast Sa2’s premium temperature is30℃, the optimal pH of growth is6.5while the optimal pH of fermentation is3.8. Compared with the Sacchromyces cerevisae1445It showed the better resistance to alcohol and sugar.(3)Key technologies of The low carbon mode production of xiaoqu were studied withsaccharifying enzyme activity as indicators. the proportion Raw to clinker, koji inoculation,additive water amount to bran, acid content, inoculation time Lactic acid to adjust pH firstuse above factors confirm the effects by the single factor experiment. And then based thesingle-factor used the orthogonal L9(34). To determine the optimum productioncondition:the ratio of raw material and clinker is4:6starter inoculation amount is0.8%water addition50%Raw acid content0.25%, culture time2days Lactic acid adjusting pHto5.0. at such condition we can get the highest quality brans.(4)Used long-shaped rice as raw material and pure rhizopus starter as saccharifyingagent under the low carbon mode using the killer yeast as leavening agents study thexiaoqu wine the production process techniques even the liquor yield and liquorquality(saccharifying temperature saccharifying time pure rhizopus start amount the addedamount of killer yeast the amount of added water and fermentation time)The optimumprocess condition of fermentation is pure rhizopus starter is0.4%, saccharifyingtemperature30℃, saccharifying time1day, the amount of added water is120%,fermentation time is4days the killer yeast added amount is0.8%.