Development of biodegradable plastics by microorganisms

塑料垃圾造成了严重的污染问题，因此开发塑料材料对地球上的自然环境产生一些负担是可取的。近年来，微生物产生的聚合物如聚-3-羟基丁酸酯(PHB)和多糖由于其可生物降解性而受到越来越多的关注。本报告描述了由1，4-丁二醇(1，4-BD)和聚(L-苹果酸)(PMLA)由葡萄糖生产PHB的微生物。1，4BD生产PHB及其降解性在P(3HB-co-4HB)共聚物的生产中，4HB是一种合适的原料，但价格较高。利用皱纹假丝酵母IFO 1364从1，4BD出发，成功地制备了4HB。以4HB为碳源，由富营养产碱菌发酵生产P(3HB-co-4HB)。用该共聚物制备的薄膜具有弹性，12周后在30ﾟC下分解。利用葡萄糖生产聚乳酸的研究。以及PMLA的一些物理化学性质。新分离的黑色酵母菌Aureobasidium sp.经多种化学分析确定为聚(β-L-苹果酸)。PMLA的相对分子质量约为10,000。培养条件实验表明，在培养基中添加CaCO3、Fe、Zn离子可提高PMLA的产量。

Plastic wastes have caused a serious pollution problem, so that it is desirable to develop plastic materials unburden some to the natural environment on the earth. Increasing attention has recently been paid to microbially produced polymers such as poly-3-hydroxybutyrate (PHB) and polysaccharides due to their biodegradability. This report describes the production of PHB from 1,4-butanediol (1,4 BD) and poly(L-malic acid) (PMLA) from glucose by these microorganisms.1. Production of PHB from 1,4 BD and degradability of the PHB In the production of P (3HB-co-4HB) copolymer, 4HB is a proper raw material, but quite expensive. We succeeded in the efficient preparation of 4HB from 1,4 BD by Candida rugosa IFO 1364. Then P (3HB-co-4HB) was produced by Alcaligenes eutrophus from the 4HB as the carbon source. The film prepared with the copolymer was elastic and it was decomposed in soil at 30ﾟC after 12 weeks.2. Production of PMLA from glucose by Aureobasidium sp. and somephysicochemical properties of the PMLA. Newly isolated black yeasts, Aureobasidium sp. were found to produce an acidic polymer, which was identified to be poly(beta-L-malic acid) by various chemical analyses. The molecular weight of the PMLA was about 10,000. The experiments on culture conditions indicated that the addition of CaCO_3, Fe and Zn ions to culture media increases the yield of the PMLA.