利用生物发酵技术制备聚合级乳酸的生产工艺

Production Process of Polymer-grade Lactic Acid by Biological Fermentation Technology

乳酸的传统下游应用集中于食品行业,但近年来以乳酸生产聚乳酸(PLA)的市场前景越发广阔。乳酸的化学纯度以及光纯度决定着下游聚乳酸产品的竞争力。详细阐述了一种利用生物发酵技术制备高纯度、高光纯聚合级乳酸的生产工艺,即通过菌种筛选预先得到发酵性能优良的鼠李糖乳杆菌,而后进行发酵、酸化、分离,得到99%化学纯度以及99%光纯度的L-乳酸。进一步探讨了新工艺中不同氮源、不同原料以及不同中和剂的选择对乳酸发酵过程的影响,据此成功建立了小试生产线,相关发明专利已获国家授权,为下游产业化生产聚乳酸奠定了原料基础。

The traditional downstream application of lactic acid is mainly focus in food industry.However,in recent years,the market demand of polylactic acid(PLA)polymerized from lactic acid is more and more brisk.The chemical and stereo-chemical purity of lactic acid determine the competitiveness of downstream PLA products.In this article,a detailed production process to get polymer-grade lactic acid with high chemical purity and high stereo-chemical purity by biological fermentation technology was described,that was,lactobacillus rhamnosus with excellent fermentation performance was obtained in advance through strain screening,and then L-lactic acid with 99%chemical purity and 99%optical purity was obtained through fermentation,acidification and separation.The influences of different nitrogen sources,raw materials and neutralizing agents on the lactic acid fermentation process were discussed.A pilot production line was successfully established,and the relevant invention patent has been authorized by China.This technology and process laid a solid foundation for the industrialization of downstream PLA production.