以乙酸钠、丙酸钠为碳源的活性污泥合成聚羟基脂肪酸酯的结构分析

聚羟基脂肪酸酯(Polyhydroxyalkanoates, PHAs)是临时储藏于活性污泥的微生物体内的能量和碳源聚合物,是完全可生物降解的热塑性塑料.为了研究碳源对PHAs结构的影响,本文采用乙酸钠、丙酸钠为碳源在厌氧条件下培养活性污泥得到2种不同的PHAs样品,通过1H NMR、13C NMR和GC-MS谱图确定其组成和比例以乙酸钠培养活性污泥得到PHAs样品的单体组成以3-羟基丁酸酯(3-hydroxybutyrate,3HB)为主,x(3HB)/x(3HV)(3-hydroxyvalerate,3-羟基戊酸酯)为93.91∶6.09;以丙酸钠培养活性污泥得到PHAs样品的单体组成主要以3HV为主,除3HB、3HV外,另外还有2-甲基-3-羟基丁酸酯(2-methyl-3-hydroxybutyrate,2M3HB)和2-甲基-3-羟基戊酸酯(2-methyl-3-hydroxyvalerate,2M3HV), 3HB/3HV/2M3HB/2M3HV的摩尔比为28.66∶63.13∶2.55∶5.66.由此可见采用不同碳源培养活性污泥所得到的PHAs的单体组成是不同的.

Polyhydroxyalkanoates of Different Structure Synthesized by Activated Sludge with Acetate and Propionate as Sole Carbon Source

Polyhydroxyalkanoates(PHAs) are Polyesters synthesized by numerous bacteria in sludge as intracellular carbon and energy storage compounds under the condition of unbalance growth. Another important aspect of PHAs is thermoplastic polyester with the remarkable characteristics of biodegradability. In this paper, in order to research the relations of carbon sources to structure of PHAs, using acetate(Ⅰ) and propionate(Ⅱ) as the unique carbon source, two kinds of PHAs samples were obtained by assimilated sludge as PHAs synthesis strains in the anaerobic process. Their structures were determined by 1H NMR 13C NMR and GC-MS. When the carbon source was acetate, the unit composition of PHAs was 93.91%(mole fraction,x) 3-hydroxybutyrate (3HB) and x=6.09% 3-hydroxyvalerate(3HV); When the carbon source was propionate, the unit composition of PHAs was x=28.66% 3HB, x=63.13% 3HV, x=2.55% 2-methy-3-hydroxybutyrate(2M3HB) and x=5.66% 2-methyl-3-hydroxyvalerate(2M3HV). It showed that PHAs obtained by activated sludge with different carbon sources composed of different monomer units.