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采用响应面分析法对影响粘红酵母细胞固定化的4个主要因素——单体浓度、交联剂浓度、包埋量、包埋时间进行了优化.首先用Plackett-Burman法设计实验对以上4个影响因素进行了评价,并筛选出显著影响因素——单体浓度和包埋量;第2步用最陡爬坡实验逼近以上两因素最优水平;最后由中心复合实验及响应面分析确定主要影响因素的最佳条件.固定化粘红酵母细胞的最优包埋条件为:单体浓度16.7%,包埋量43%,交联剂浓度2.0%,包埋时间45min.在此条件下得到的固定化细胞与游离细胞相比,酶活保留率可达63%,较优化前提高了31%.实验室制备试验中L-苯丙氨酸(L-Phe)积累浓度可达53.3g/L,与该菌株的中试游离整细胞一次批式转化产L-Phe浓度30g/L比较,产率提高了1.8倍.图3表9参15
Response surface methodology was used to optimize the four factors influencing the immobilization of Rhodotorula glutinosa cells, such as monomer concentration, concentration of crosslinker, encapsulation amount and embedding time.First, Plackett-Burman method 4 influencing factors were evaluated, and significant influencing factors - monomer concentration and embedding volume were screened out. In the second step, the steepest ascent was used to approximate the optimal level of the above two factors. Finally, the central composite experiment and response surface analysis The optimal conditions for determining the main influencing factors were as follows: the optimum embedding conditions of immobilized Rhodotorula glutinis cells were: monomer concentration 16.7%, entrapment 43%, cross-linker concentration 2.0%, embedding time 45 min.In this condition Compared with free cells, the immobilized cells obtained under the conditions of enzymatic activity retention rate up to 63%, compared with the pre-optimization increased by 31% .L-Phe concentration in laboratory preparation experiments up to 53.3 g / L, compared with the yield of L-Phe 30g / L produced by batch transformation of the free cell from the pilot plant of this strain, the yield increased by 1.8 times.