Lactic acid is precursor of poly lactic acid which is a kind of biomedical engineering materials. Recently, with the rapid development of biodegradable materials-poly lactic acid, there has been an high interest in lactic acid production. 乳酸是生物医学工程材料聚乳酸的生产原料,而且随着生物可降解材料-聚乳酸研究的迅速发展,乳酸的生产越来越受到人们的高度关注。