细胞生长、葡萄糖代谢及副产物重新利用对法夫酵母虾青素合成的影响分析

Influence of Cell Growth, Glucose Consumption and By-products on Astaxanthin Synthesis with Phaffia rhodozyma Fermentation

以两株产虾青素法夫酵母菌株为研究对象,分别在不同摇床转速、初始葡萄糖浓度、乙醇的存在与否等培养条件下,考察葡萄糖浓度、添加乙醇及溶氧状况对法夫酵母细胞生长、代谢副产物产生的影响及其与虾青素合成之间的关系,进一步阐明法夫酵母虾青素合成的机理。实验结果表明:法夫酵母JMU-VDL668菌株的生长速率、葡萄糖代谢速率和乙醇积累量均高于法夫酵母JMU-MVP14菌株,但前者的虾青素合成速率却远低于后者;当发酵液中的葡萄糖含量降低时,酵母细胞对糖代谢副产物进行二次利用,导致有利于虾青素合成的情况出现,虾青素产量得到进一步提高;在初始培养基中添加1 g?L?1乙醇能够在一定程度上促进虾青素的合成。

jUsing two astaxanthin-producing strains - Phaffia rhodozyma JMU-VDL668 and Phaffiarhodozyma JMU-MVP14 as the subjects, this study investigates the effects of cell growth and metabolism onastaxanthin synthesis under different affecting factors, such as shaking speed, initial glucose concentration andethanol contents. Moreover, the research looks into the relationship between byproducts of cell growth andmetabolism and experimental conditions such as glucose concentration, ethanol contents and dissolved oxygen.The results show that the growth rate, glucose consumption rate and ethanol accumulation of P. rhodozymaJMU-VDL668 are higher than those of P. rhodozyma JMU-MVP14, but the astaxanthin accumulation is muchless with P. rhodozyma JMU-VDL668. Meanwhile, when the glucose concentration is close to zero, theby-products of glucose metabolism could be reused by yeast cells, which is good for astaxanthin synthesis andcan further enhance intracellular astaxanthin concentration. By adding 1 g.L-1 ethanol into the initial medium,the astaxanthin synthesis process can be improved.