共查询到18条相似文献,搜索用时 62 毫秒
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低温锻炼技术被广泛地应用到实际活性干酵母的活化过程中,该文以普通酿酒酵母和经低温锻炼的酿酒酵母BH8为实验材料分别对葡萄汁进行发酵实验。实验结果表明,在13 ℃的低温发酵条件下,经过低温锻炼的酿酒酵母与对照相比发酵时间缩短2 d,发酵效率提高了7.41%;最大活菌数增加了8.33%;残糖量降低了16.28%;乙醇含量增加了4.04%;乙酸含量降低了6.70%。然而其甘油、海藻糖和琥珀酸的含量却低于对照组,这很可能是由于酿酒酵母在低温锻炼过程中已经产生了抗低温胁迫的原因。 相似文献
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以sod1Δ、sod2Δ、sod1Δsod2Δ酿酒酵母基因缺失菌株为遗传材料,采用休止细胞梯度生长法,分析SOD1和SOD2基因缺失对高温、乙醇毒性、高渗透压、高盐、乙酸毒性及营养饥饿胁迫条件耐受性的影响。结果显示,与野生型菌株相比,sod1Δ菌株对高温、高渗透压和乙酸胁迫的耐受性降低;sod2Δ菌株耐受性无明显变化;sod1Δsod2Δ双缺失菌株对高温、乙醇毒性、乙酸毒性、高渗透压和高盐的耐受性均下降,表明酵母超氧化物歧化酶基因与多种胁迫耐受性密切相关。 相似文献
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酿酒酵母是生产酒类产品的主要微生物,而生产中的发酵环境对酿酒酵母来说是一种不利的生长代谢环境,存在多种胁迫因素,其中就包括弱有机酸引起的低pH胁迫。酿酒酵母应对胁迫环境,有自身一套完备的适应机制,不同胁迫应对机制既有相同之处亦有不同之处。本文概括了近年来酿酒酵母对弱有机酸应激机制的研究热点,主要从弱有机酸胁迫的基因表达、转录表达以及蛋白质表达3个水平进行阐述,涉及ATP结合区转运子Pdr12及其转录因子War1p,HOG-MAPK途径,水通道蛋白Fps1p,质膜H+-ATP酶,SOD,CAT,以及弱有机酸与其他胁迫的交互作用,旨在为更好地研究酿酒酵母的弱有机酸应激机制提供一定的参考。 相似文献
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Marian Redón Anna Borrull Maria López Zoel Salvadó Ricardo Cordero Albert Mas José Manuel Guillamón Nicolas Rozès 《Yeast (Chichester, England)》2012,29(10):443-452
The phospholipid metabolism of Saccharomyces cerevisiae plays a central role in its adaptation to low temperatures. In order to detect the key genes in this adaptation, various phospholipid mutants from the EUROSCARF collection of Saccharomyces cerevisiae BY4742 were tested to ascertain whether the suppression of some genes could improve the fermentation vitality of the cells at low temperature. The cell vitality and phospholipid composition of these mutants were analysed. Some knockouts improved (hmn1Δ) or impaired (cho2Δ and psd1Δ) their vitality at low temperature (13 °C) but were not affected at optimum temperature (25 °C). A common trait of the mutants that had some defect in vitality was a lower concentration of phosphatidylcholine and/or phosphatidylethanolamine. The supplementation with choline allowed them to recover viability, probably by synthesis through the Kennedy pathway. Hmn1Δ showed a lower concentration of phosphatidylcholine, which explains the dominant role of the de novo pathway in cellular phosphatidylethanolamine and phosphatidylcholine vs the Kennedy pathway. The absence of such genes as CRD1 or OPI3 produced important changes in phospholipid composition. Cardiolipin was not detected in crd1Δ but phosphatidylglycerol circumvents most of the functions assigned to CL. The considerable reduction in PC diminished the cell vitality of opi3Δ at both temperatures, although the decrease at 13 °C was more marked. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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葡萄酒的酒精发酵主要是由酿酒酵母(Saccharomyces cerevisiae)完成的,不同的培养条件会影响酿酒酵母的发酵效率。该文以模拟葡萄汁代替天然葡萄汁进行试验,考察环境温度、摇床转速以及发酵基质pH对酿酒酵母的影响。试验结果显示,在18~33 ℃温度范围内,随着温度的升高,发酵效率逐渐增大。28 ℃是最适宜酵母生长的温度条件。在50~150 r/min范围内,随着转速的增大,酵母的发酵效率逐渐增加,所需发酵时间逐渐缩短,以150 r/min为最适转速。在葡萄酒酿造常用的pH范围内,酿酒酵母的生长和发酵情况随pH的升高而增强,在pH值为4.0时达到最佳生长和发酵效率。 相似文献
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以实验室现有菌种AY12a为出发菌株,URA3基因作为筛选标记,利用胞内重组,在MSN4基因的N端加上强启动子PGK1p以实现基因的过表达,最终通过多聚酶链式反应(PCR)验证,成功构建突变株AY12a-msn4。结果表明,该突变株具有一定的耐高温性能,在55 ℃条件下热击后仍能正常生长。同时将突变株AY12a-msn4与出发菌株AY12a进行玉米高温浓醪发酵,并测定发酵完成后的酒精度、残糖、48 h细胞存活率、CO2失重及发酵时间。结果表明,突变株AY12a-msn4发酵液酒精度提高3.85%,48 h细胞存活率上升,残糖含量下降14.5%。 相似文献