机械化生产黄酒酵母菌性能的研究

针对“三边发酵“理论中黄酒酵母菌性能的要求,通过研究黄酒酵母在TTC培养基中的变色情况、发酵力情况、糖化酶糖液中酵母生长情况、酵母耐酒精度、酵母形态和产香、酵母醭生成情况、酵母起发速度、酵母巨大菌落形态、酵母死灭温度、酵母与杆菌在MRS液体培养基中共同生长和凝聚情况及在锥形瓶中发酵试验.从中筛选出2#和3#酵母菌株搭配使用,更加适宜于机械化黄酒中的大罐发酵.     

Continuous ethanol fermentation from non-sulfuric acid-washed molasses using traditional stirred tank reactors and the flocculating yeast strain KF-7

Waste molasses is one of the most important feedstock for ethanol production in Brazil as well as in many Southeast Asian countries, including China. Sulfuric acid pretreatment is employed in most ethanol distilleries in China to control bacterial contamination, which results in difficulties in the treatment of wastewater containing high levels of sulfate ions. In this study, a high efficiency, non-sterilized, continuous ethanol fermentation process without sulfuric acid pretreatment was developed using the flocculating yeast strain KF-7 and the widely utilized, traditional, stirred tank reactors. An alternative molasses medium feeding method, which differs from traditional methods, is proposed that effectively controls bacterial contamination. Separate feeding of 1.2-fold diluted molasses and tap water into the reactor proved to be effective against bacterial contamination during long-term continuous fermentation. By feeding yeast cells with high metabolic activity to the second reactor, a two-stage continuous fermentation process that yielded a high ethanol concentration of 80 g/l as well as high ethanol productivity of 6.6 g/l/h was successfully operated for more than one month. This fermentation process can be applied to ethanol distilleries in which traditional tank reactors are used.     

Two-dimensional electrophoretic separation of yeast proteins using a non-linear wide range (pH 3–10) immobilized pH gradient in the first dimension; reproducibility and evidence for isoelectric focusing of alkaline (pI >7) proteins

The proteome of the yeast Saccharomyces cerevisiae was analysed by two-dimensional (2D) polyacrylamide gel electrophoresis utilizing a non-linear immobilized pH gradient (3–10) in the first-dimensional separation. Cells were labelled by [³⁵S]methionine incorporation in the respiro-fermentative phase during exponential growth on glucose. Gels were run, visualized with phosphoimager technology and all resolved proteins automatically quantified. Proteins were well resolved over the whole pH interval, and evidence for isoelectric focusing on the basic side of the pattern was generated by sequencing of some spots, revealing the 2D positions of Tef1p, Pgk1p, Gpm1p, Tdh1p and Shm2p. Roughly 25% of the spots were resolved at the alkaline side of the pattern (pI>7). The position reproducibility was high and in the range 1–2 mm in the x-and y-dimension, respectively. No quantitative variation was linked to a certain size or charge class of resolved proteins, and the average quantitative standard deviation was 17±11%. The obtained immobilized pH gradient based pattern could easily be compared to the old ampholine-based 2D pattern, and the previously reported identifications could thus be transferred. Our yeast pattern currently contains 43 known proteins, all identified by protein sequencing. Utilizing these identified proteins, relevant pI and Mr scales in the pattern were constructed. Normalization of the expression of identified spots by compensating for the number of methionine residues a protein contains allowed stoichiometric comparisons. The most dominant proteins under these growth conditions were Tdh3p, Fba1p, Eno2p and Tef1p/Tef2p, all being expressed at more than 500 000 copies per cell. The differential carbon source response during exponential growth on either glucose, galactose or ethanol was examined for the alkaline proteins identified by micro-sequencing in this study. © 1997 John Wiley & Sons, Ltd.