表面活性剂在生物转化法合成普鲁兰中的作用及生理机制

考察斯潘类和吐温类表面活性剂在利用出芽短梗霉全细胞生物转化合成普鲁兰多糖中的作用，结果发现20 g/L斯潘80和5 g/L吐温80将细胞的普鲁兰合成能力分别提高了46.5%和32.9%，二者复配使用进一步提高了普鲁兰产量和合成效率。通过对相关生理生化参数进行测定，发现斯潘80和吐温80增加了细胞膜的通透性，提高了普鲁兰合成关键酶的活性，提升了胞内尿苷二磷酸葡萄糖和能量物质ATP的水平，加速了ATP的再生，在促进物质和能量代谢的基础上，实现了普鲁兰产量和合成效率的提高。研究结果部分解析了表面活性剂提高普鲁兰合成效率的生理机制，同时也为其他类似结构微生物多糖的高效合成提供技术参考。

Physiological Mechanism of the Effect of Surfactants on Pullulan Production by Bioconversion

The effects of surfactants, Span and Tween, on pullulan production by bioconversion using whole cells of Aureobasidium pullulans were investigated. The pullulan biosynthesis capability of these cells was increased by 46.5% and 32.9%, respectively, when Span 80 (20 g/L) and Tween 80 (5 g/L) were added individually into the bioconversion broth. The combination of the two surfactants further improved the yield and efficiency of pullulan production. Based on the determined physiological and biochemical parameters, Span 80 and Tween 80 were found to improve the permeability of the cell membrane, increase the activities of the key enzymes involved in pullulan biosynthesis, elevate the levels of intracellular uridine diphosphate glucose and energy substance ATP, and accelerate the rate of ATP regeneration, promoting the metabolism of substance and energy and ultimately resulting in improvement in the yield and efficiency of pullulan production. The results presented in this study partly elucidate the physiological mechanism underlying the increase in efficiency of pullulan production by surfactants and also provide a technical basis for efficient production of other analogous microbial polysaccharides.