扣囊复膜酵母菌高产突变株转化可溶性淀粉生产海藻糖的研究

以前的研究曾发现扣囊复膜酵母菌 (Saccharomycopsisfibuligerasdu)能利用可溶性淀粉发酵累积质量浓度为 180 g/L的海藻糖。然而 ,该菌株含有高活性的酸性和中性海藻糖酶 ,使发酵过程中海藻糖的累积下降。为了提高海藻糖的产量 ,去除海藻糖酶的活性是必要的。野生型菌株通过EMS的诱变作用 ,筛选出了 1株不能同化海藻糖 ,但生长速率不变的突变株。该突变株与野生型菌株相比能够利用淀粉发酵累积更高含量的海藻糖 ,与野生型菌株相比 ,突变株细胞的酸性海藻糖酶的活性低 3倍 ,中性海藻糖酶的活性低 3 7倍。这意味着酸性和中性海藻糖酶活性的降低对该突变株的海藻糖产量的提高起关键作用

Studies on Enhanced Conversion of Soluble Starch to Trehalose by a Mutant of Saccharomycopsis fibuligera

The previous studies found that Saccharomycopsis fibuligera sdu could accumulate 18% (w/v) trehalose from soluble starch However, the yeast strain contains high activities of acid and neutral trehalase which can mobilize trehalose accumulated during fermentation In order to enhance the yield of trehalose, it is necessary to remove the trehalase activities from the cells By mutagenesis of EMS, one mutant which could not assimilate trehalose, but could grow as fast as its wild type, was isolated This mutant could accumulate much higher amount of trehalose from starch than its wild type The acivity of its acid trehalase is 3 times lower than its wild type and the activity of its neutral trehalase is almost 37 times lower than its wild type The reduction in acid trehalse activity, especially neutral trehalse activity is responsible for the increased yield of trehalose accumulated by the mutant