Multi-Scale Optimize The Immobilized Of Molasses Alcohol Yeast Cells And Research Its Biological Characteristics

Molasses is the by-products of sugar industry, which has the feature of production concentration, large output, etc. At present, molasses are mainly used for alcoholic fermentation. This research is mainly to optimize the immobilized of yeast cells.The main research results are as follows:(1) By comparing the six brewing yeast strains (Starch yeast A, Molasses alcohol yeast Ag、A、A6、B2、D4screened by domesticated AS2.1190) from colonial morphology and ferment ability to screen the most suitable wine yeast strains used for immobilization. The results indicate that the molasses alcohol yeast A43was the best yeast among six candidates of molasses alcohol yeast.(2) By comparing the mechanical strength, mass transfer properties, and fermentation performance of Alginate-Ca, PVA and PVA-Alginate-Ca, the results indicate that PVA-Alginate-Ca have the higher mechanical strength, better transfer properties and stronger fermentation performance, so it has the potential of industrial application. Compare the effect of different treatment and the molding process method on composite material immobilized yeast, we use the single factor and orthogonal experiment to optimize the preparation of composite PVA-Alginate-Ca immobilized carrier conditions. The sequence of factors which have effects on ethanol content was SA concentration> PVA concentration> shape of the carrier. The highest ethanol content was1.0%concentration of sodium alginate,9.0%concentration of PVA, and granular shape. Considering the two aspects from practical industrial production and continuous fermentation process, we decided to take repeated freezing-thawing into honeycomb briquette processing method to preparation of immobilized yeast. According to the optimal preparation process, the immobilized molasses alcohol yeast mechanical strength is37.52gmm-2, the mass transfer resistance is0.1935, and the alcohol content is12.18%.(3) Select the four factors of brix, initial pH, fermentation temperature and the immobilized yeast inoculation quantity, through the single factor experiment and choose the table L16(45) orthogonal experiment to optimize the immobilized yeast fermentation conditions. The sequence of factors which have effects on ethanol content was brix> fermentation temperature> inoculation quantity> initial pH. The optimal fermentation conditions was initial pH (3.5), inoculation quantity (4%) and brix (32°Bx) at34℃.