Lactose uptake rate measurements by C-labelled lactose reveals promotional activity of porous cellulose in whey fermentation by kefir yeast

Lactose uptake rate by kefir yeast, immobilized on tubular cellulose and gluten pellets during fermentation of lactose and whey, was monitored using ¹⁴C-labelled lactose. Results illustrated that, in all cases, lactose uptake rate was strongly correlated with fermentation rate and the fermentation’s kinetic parameters were improved by kefir yeast entrapped in tubular cellulose. As a result, twofold faster fermentations were achieved in comparison with kefir yeast immobilized on gluten. This is probably due to cluster and hydrogen bonds formation between cellulose and inhibitors, such as Ca⁺⁺ and generated lactic acid, by which they leave the liquid medium. The findings, regarding the promotional effect of cellulose, seem promising for application in industrial whey fermentations.     

采用高压CO2气体灭活啤酒酵母的试验研究

本文对啤酒酵母溶液采用高压CO2气体杀菌过程进行了试验研究。试验表明，向啤酒酵母溶液中通入高压CO2气体，对啤酒酵母有明显的杀灭作用。CO2气体压力、通气时间、酵母溶液浓度、微孔气体分配管孔径等参数对杀菌效果有明显影响。在1MPa的CO2压力下，通气4min，即可达到37．2％的杀菌率。     

Effect of Disruption Methods on the Dead-End Microfiltration Behavior of Yeast Suspension

High voltage electrical discharges (HVED) and high pressure homogenization (HPH) were compared for extracting intracellular compounds from yeasts. The efficiency of cell disruption was evaluated by measurements of electrical conductivity, UV-spectroscopy, etc. It was shown that the HPH permits better extraction than HVED. The filtrations of yeast suspension were studied in a dead-end stirred cell. The filtration of untreated, HVED and HPH treated yeast suspensions without stirring was governed by cake formation mechanism. The filterability of HVED and especially HPH-treated yeast suspension was very low. Under stirring, different filtration mechanisms were observed for untreated and treated yeast suspensions.     

Microalgal biomass as a fermentation feedstock for bioethanol production

BACKGROUND: The increasing cost of fossil fuels as well as the escalating social and industrial awareness of the environmental impacts associated with the use of fossil fuels has created the need for more sustainable fuel options. Bioethanol, produced from renewable biomass such as sugar and starch materials, is believed to be one of these options, and it is currently being harnessed extensively. However, the utilization of sugar and starch materials as feedstocks for bioethanol production creates a major competition with the food market in terms of land for cultivation, and this makes bioethanol from these sources economically less attractive. RESULT: This study explores the suitability of microalgae (Chlorococum sp.) as a substrate for bioethanol production via yeast (Saccharomyces bayanus) under different fermentation conditions. Results show a maximum ethanol concentration of 3.83 g L^?1 obtained from 10 g L^?1 of lipid‐extracted microalgae debris. CONCLUSION: This productivity level (～38% w/w), which is in keeping with that of current production systems endorses microalgae as a promising substrate for bioethanol production. Copyright © 2009 Society of Chemical Industry     

Fining of red wines with gluten or yeast extract protein

Due to a growing interest in alternatives to substitute gelatin as clarifying agent, this work investigates the use of yeast extracts and glutens. Physico‐chemical characteristics of proteins were analysed. Fining experiments were carried out on young red wines. Turbidity reduction, lees volume and effects on polyphenolic content and colour characteristics were determined. The results indicated that glutens and yeast extracts turbidity reduction is comparable to gelatin. Lees production was considerably reduced by non‐animal proteins: yeast extracts produced 44%, wheat glutens 60% and maize gluten 92% less than gelatin. Lees volume is highly correlated (R = ?0.720) with the absolute superficial charge density value (SCD) and with the pI (0.936) when clarifier was used in combination with bentonite. Treatments with glutens reduced less the polyphenolic content (between 0.6 and 8.7 units) than gelatin did. There were slight differences on the modification of colour intensity.     

固定化酵母载体材料的研究及应用

对聚乙烯醇（ＰＶＡ）和海藻酸钠两种载体材料用于产酯酵母细胞的固定化方法和性能进行了比较。结果是ＰＶＡ比海藻酸钠优越。在上述研究的基础上，应用固定化酵母利用酒厂酒尾产酯，获得了高产乙酸乙酯的结果。利用固定化酵母发酵的酯香液提高白酒质量取得了良好的效果。     

产酯活性干酵母的研究

本文研究在收集到的三株优良产酯酵母中，优选出一株产酯力最高的酵母菌株１３１２，并以此为生产菌株，试制产酯活性干酵母（ＡｃｔｉｖｅＤｒｙＹｅａｓｔ，简称ＡＤＹ）．同时，应用产酯ＡＤＹ进行提高白酒质量的试验．产酯ＡＤＹ对白酒总酯含量及风味有一定的提高和改善作用．本试验对改造白酒传统生产技术具有积极意义．     

酵母流加培养的参数检测与控制

在酵母流加培养过程中，因缺乏应用的传感器，不能在线检测菌体浓度等参数。本文把可测得且又与菌体生长密切相关的氧吸收率作为被控参数，用呼吸商判别代谢途径，采用预估校正算法控制基质的流加量。     

饲料酵母的快速活菌计数法

将样品研磨稀释，用美兰染色，制成染色活菌液，以纽巴氏计数板载液，置显微镜下，统计一个大方格中的活菌数，乘以稀释倍数，即可得出单位重量样品中的活菌含量。     

快速酿造葡萄酒酵母的筛选

通过SO2、酒精和高酸度的耐受性实验，从22株葡萄酒酵母菌中筛选出若干株发酵能力和耐受性均较高的优良菌株，用于低档葡萄快速发酵生产。实验的极限值为：在初发酵液中，SO2的含量为250mg/L，酒精浓度为18％，pH值为2．7。经验证，用筛选株12号菌生产的红葡萄酒可以达到国家标准。