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摘要：聚苹果酸（poly(malic acid), PMA）是一种以L—苹果酸为唯一单体、完全生物可降解的高分子聚合物，它具有高度水溶性、生物相容性、生物可降解性及化学修饰性等优良性质，在作为药物载体、生物医学材料等方面具有广阔的应用前景。 PMA可通过生物发酵法制备，生产成本过高依然是目前制约PMA产业化的最大问题之一，降低原料成本是实现PMA大规模生产的重要保障。本论文以出芽短梗霉Aureobasidium pullulans HA-4D为研究对象，以制糖工业副产物甘蔗糖蜜为原料，进行PMA发酵研究。甘蔗糖蜜经过硫酸水解和亚铁氰化钾沉淀复合处理后，PMA摇瓶发酵产量达28.5 g/L，比没有经过预处理的上升了120 %。在5 L发酵罐上进行补料分批发酵，糖蜜初始总糖浓度为100 g/L，当总糖浓度下降至20 g/L时补料，使总糖浓度上升至130 g/L，发酵168 h后PMA终浓度达到70.2 g /L。本研究节约了大量的原料成本，为实现绿色环保、经济有效的PMA工业生产打下了良好的基础。70582
毕业论文关键词：聚苹果酸，甘蔗糖蜜，发酵技术
Abstract： Poly(malic acid) is formed by L-malic acid as only monomer and linked each other with ester bond, PMA have lots of excellent characteristics, including highly water-soluble, biocompatible, biodegradable and can be chemically modified, etc. And PMA is being developed for pharmaceutical carrier, biomedical materials, etc. based on these characteristics. Nowadays, PMA can be prepared by microbial fermentation, the high cost of production is still one of the problems to restrict the industrial utilization of PMA. Reducing raw material cost is the most important guarantee for large scale PMA production. Therefore, Aureobasidium pullulans HA-4D, a high PMA-producing strain, was used to study PMA fermentation using cheap raw materials in this study. The cane molasses, which is a by-product of sugar industry, was used as cheap raw materials. The cane molasses was pretreated with H2SO4 hydrolysis combined with potassium ferrocyanide precipitation. PMA concentration achieved 28.5 g/L in shake flask, which was increased by 120 % than that of untreated cane molass. Fed-batch fermentations were performed in 5 L fermentor, the initial total sugar concentration of pretreated cane molasses was 100 g/L, when the total sugar was decreased to 20 g/L, feeding solution was added to increase the total sugar concentration to 130 g/L, the final concentration of PMA was 70.2 g/L after 168 h fermentation. This study saved much cost of raw materials for PMA fermentation, and it is helpful for industrial PMA production with a green, economical and efficient method.
Keywords: Poly(malic acid); cane molasses ；fermentation technology;
目 录
第一章.前言 5
1 聚苹果酸概述 5
1.1 聚苹果酸的结构 5
1.2 聚苹果酸的性质 6
1.3 聚苹果酸的用途 6
1.3.1聚苹果酸作为药物载体及微胶囊材料 6
1.3.2聚苹果酸作为生物医学材料 6
1.3.3聚苹果酸作为吸水材料 7
1.4 聚苹果酸的制备 7
1.4.1化学法合成聚苹果酸 7
1.4.2生物法合成聚苹果酸 7
1.5 聚苹果酸廉价碳源研究情况 8
1.6 糖蜜作为廉价碳源用于发酵生产 9
1.7本论文研究内容及意义