发酵液中1,3-丙二醇分离提取的研究进展

1,3-丙二醇是合成聚乳酸的主要原料,以甘油为底物的生物法制备1,3-丙二醇是以绿色化学为特征的技术。但1,3-丙二醇极性很强、微生物发酵液成分较复杂,产品收率偏低,质量难符合制备高性能聚对苯二甲酸丙二醇酯的要求,故1,3-丙二醇的分离提纯成为了生物法合成技术的关键。对于1,3-丙二醇发酵液,提纯过程包括发酵液预处理、脱盐和浓缩提纯。本文讨论了用于1,3-丙二醇提纯的主要技术,包括采用离心、过滤、絮凝脱大分子物质,用离子交换、电渗析、双水相萃取或有机溶剂沉淀等方法脱盐类,及通过精馏、萃取、吸附对发酵液浓缩提纯,或是以上某几个分离工艺的组合。提出整个分离工艺仍存在很多问题,对各工艺路线不断进行优化,开发新的经济高效的分离提取工艺路线,是目前实现规模化生物法生产1,3-丙二醇的技术重点。

Process of separating and purifying 1,3-propanediol from fermentation broth

1, 3-propanediol is the main raw material to synthesize PTT. Using glycerol to produce 1, 3-propanediol by biological processes is characteristic of green chemistry. Due to the strong polarity of 1, 3-propanediol and complex composition of fermentation broth, 1, 3-propanediol has a low yield and its quality cannot match the requirements for synthesizing high performance PTT. Therefore, the separation and purification of 1, 3-propanediol from fermentation broth become the key technology for biosynthesis. There are several steps to realize it, including pretreatment of fermentation broth, desalination, concentration and purification. In this paper, the main methods for separating 1, 3-propanediol were discussed. It can be described as the following: centrifugation, filtration and flocculation process can be applied to remove macromolecular substances, and then 1, 3-propanediol can be concentrated and purified by icon exchange, electrodialysis, aqueous two-phase extraction, ethanol precipitation to desalt, adopting distillation, extraction and adsorption. It can also be achieved by one or two above processes combined together. There still exist some problems in the whole separation. Each process needs continuously optimized to obtain an economical and efficient separation route. This is the key technology to realize large-scale production of 1, 3-propanediol using biological process.