糖浓度对酒精酵母GJ2008果糖与葡萄糖利用差异性的影响

在不同糖浓度条件下,以YPDF培养基模拟甘蔗汁进行酒精发酵,测定过程中各参数的变化,并对果糖与葡萄糖消耗过程进行曲线拟合,以拟合方程计算出果糖与葡萄糖代谢一半和代谢完全所需时间.结果表明,糖浓度为90gL～270g/L,酵母GJ2008始终会偏用葡萄糖,果糖利用一直受到葡萄糖的竞争性抑制.糖浓度为90g/L时,细胞生长受糖浓度抑制程度最小,但乙醇产率较低;糖浓度为230g/L,发酵液中葡萄糖含量较低时,果糖受葡萄糖的竞争性抑制得到了解除,果糖的利用急剧加快;糖浓度为250g/L和270g/L,发酵液中葡萄糖含量较低时,果糖受葡萄糖的竞争性抑制得到了解除,但果糖的利用并没有加快,表现为后期酵母数维持值较低.糖浓度对果糖代谢的影响要大于对葡萄糖代谢的影响,较低糖浓度有利于后期果糖与葡萄糖利用差异性的缩小.

Effect of sugar concentration on discrepancy in fructose and glucose utilization during ethanol fermentation by Saccharomyces cerevisiae GJ2008

YPDF basic medium was used to simulate sugarcane juice to conduct ethanol fermentation at different sugar concentrations.Parameters along the fructose and glucose consumption process were determined for curve fitting,and through the fitting equation to calculate the time needed for both half and full metabolism of fructose and glucose.Saccharomyces cerevisiae GJ2008 always showed a priority in using glucose when the sugar concentration was 90g/L to 270g/L,so the fructose utilization was always in competitive inhibition.The cell growth was least affected at the sugar concentration of 90g/L,but a relatively lower productivity of ethanol production.For sugar concentration of 230g/L,fructose consumption accelerated rapidly due to the competitive inhibition released by the low concentration of glucose in the fermentation liquor.For sugar concentration of 250g/L to 270g/L,competitive inhibition of fructose was released by the lower concentration of glucose.However,the late cell generation became lower instead of fructose consumption speeding up.Data suggested that sugar concentration affected more in fructose consumption than glucose consumption,and lower sugar concentration could result in a lower discrepancy in fructose and glucose utilization.