乳化-内部凝胶化工艺制备固定化酵母微胶囊

乳化-内部凝胶化技术可制备粒径可控且分布较均匀的海藻酸钙凝胶微球，其工艺易于放大以实现工业规模生产，因而已被用于蛋白、多肽类药物的缓控释载体和酶的固定化研究。本文提出将乳化-内部凝胶化工艺用于微生物固定化培养的研究，以啤酒酵母S.cerevisiae BY4741为模型，重点考察了乳化-内部凝胶化工艺过程相关参数对微生物活性的影响规律，发现酸是影响其活性的主要因素。因此，从内部凝胶化的原理入手，确定了适合微生物包埋的工艺条件，制备过程中微生物活性可保持77.0%，凝胶微球体积产率93.5%。进而制备载细胞海藻酸钠-壳聚糖微胶囊(AC微胶囊)，考察AC微胶囊固定化培养过程中啤酒酵母的生长动力学，结果表明：在细胞增殖过程中，微胶囊形态保持良好，酵母菌的生长动力学明显优于游离培养组。因此，乳化-内部凝胶化工艺有望成为规模化微生物固定化培养和生产的新技术。

Preparation of microcapsules for immobilization of Saccharomyces cerevisiae by emulsification-internal gelation technology

The emulsification-internal gelation technology has attracted considerable interest in scale-up preparation of calcium alginate gel beads with controllable size and uniform size distribution, and has been used as controlled release carriers of enzymes, proteins and poly-peptide drugs and in immobilization of enzymes. In this paper, the idea of preparing immobilization carrier of microbes using the emulsification-internal gelation technology was put forward with S. cerevisiae BY4741 (yeast cells) as a model. The influence of process parameters on the survival rate of microbes was firstly evaluated, which showed that acetic acid was harmful to yeast cells. Based on the mechanism analysis of internal gelation, the process parameters were adjusted and improved to benefit the survival and growth of microbes. As a result, the survival rate of yeast cells could reach 77.0%, and the volumetric yield rate of gel beads was 93.5%. Furthermore, alginate-chitosan (AC) microcapsules entrapping yeast cells were prepared, and the growth kinetics of AC microencapsulated yeast cells was investigated. The results showed that AC microcapsules kept intact with the immobilized culture process, and the growth kinetics of AC microencapsulated cells was better than that of free culture. Therefore, the emulsification-internal gelation technology is expected to be used for the scale-up production of high-value drugs or fine chemicals with immobilized culture of microbes.