固定化酵母生产L－间羟基苯基乙酰基甲醇的研究

Studies on Production of L-m-Hydroxyphenyl Acetyl Carbinol by Immobilized Yeast Cells

报道间羟基苯基乙酰基甲醇的高产酵母菌株筛选，并将其固定化，海藻酸钙包埋法比聚乙烯醇（ＰＶＡ）－海藻酸钙包埋法效果好，其浓度为１％，包埋量为３ｇ／１０ｍｌ。固定化细胞的最佳底物浓度、糖浓度和最佳反应时间与游离细胞一致，分别为１０ｍｇ／ｍｌ、１００ｍｇ／ｍｌ和６ｈ；但最适反应温度比游离细胞高５℃，为３０℃；最佳ｐＨ比游离细胞高１～２个ｐＨ单位，为ｐＨ６。固定化细胞能反复用于羟基苯基乙酰基甲醇生产５次。但在柱式反应器中，转化效率大大下降。固定化细胞在４℃时贮存３０ｄ活性基本上无损失。

A yeast strain S. cereisiae CPU 93-1 with high m-hydroxyphenyl acetyl carbinol(HPAC)producing capacity was found out from 6 strains of genera Saccharomyces.The immobilization of S.cerevisiae CPU 93-1 using the PVA-calcium alginate entrapment,which was superior to PVA-calcium alginate,was investigated.Biomass of 3 g of wet cells entrapped in 10 ml of 1% of alginate solution was shown to be favourable.Comparison of the kinetics,of reaction of calcium alginate-immobilized cells and free cells showed that optimal concentration of substrate( m-hydroxybenzaledyde),optimal glucose concentration and optimal reaction time were same in both systems:10 mg/ml, 100mg/ml and 6 h, respectively.The optimal reaction temperature of immobilized cells was 30℃,which was 5℃ higher than that of free cells.The immobilization of cells gave rise to increase of pH 1～2 in optimal reaction pH,which was pH 4～5 in free cells, and HPAC preduction can be performed with calcium alginateimmobilized cells semicontinuously over 5 cycles without loss of activity. The production effciency of immobilized cells was greatly lowered when biotransformation was carried out in column reactor under the same conditions as the batch reaction, Immobilized cells can be stored at 4℃ for 30 days without loss,of activity.