Attfield P V, Kletsas S
Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.
Lett Appl Microbiol. 2000 Oct;31(4):323-7. doi: 10.1046/j.1472-765x.2000.00825.x.
Four strains of bakers' yeast were analysed for their hyperosmotic responses when in media that mimic conditions occurring in bread doughs. Two of the strains produced strong fermentative activity in medium with low osmotic stress, but produced considerably less ethanol in high sucrose concentration medium. Two other strains produced more similar fermentation activities across the range of media tested. The strains that were inhibited by high sucrose concentration were unable to produce significant amounts of glycerol under hyperosmotic conditions. By contrast, the yeasts that were not inhibited significantly by high sucrose produced a considerable amount of glycerol. The strains that produced significant glycerol exhibited efficient expression of the glycerol-3-phosphate dehydrogenase gene GPD1. These novel data on the molecular responses of industrially relevant strains of bakers' yeasts are prerequisite to designing strategies for improving the performance of industrial yeasts in high sugar concentration media.
对四种面包酵母菌株在模拟面包面团条件的培养基中的高渗反应进行了分析。其中两种菌株在低渗透胁迫培养基中产生强烈的发酵活性，但在高蔗糖浓度培养基中产生的乙醇要少得多。另外两种菌株在测试的一系列培养基中产生的发酵活性更为相似。被高蔗糖浓度抑制的菌株在高渗条件下无法产生大量甘油。相比之下，未被高蔗糖显著抑制的酵母产生了大量甘油。产生大量甘油的菌株表现出甘油-3-磷酸脱氢酶基因GPD1的高效表达。这些关于工业相关面包酵母菌株分子反应的新数据是设计提高工业酵母在高糖浓度培养基中性能策略的先决条件。
