School of Environment, Tsinghua University, Beijing 100084, China.
Bioresour Technol. 2013 Jul;140:328-36. doi: 10.1016/j.biortech.2013.04.105. Epub 2013 May 6.
The dynamic process of polyhydroxyalkanoates (PHA) synthesis by bacterial consortium in substrates simulating the excess sludge fermentation liquid was in-depth investigated in this study. The maximum PHA content and PHA yield was obtained with 62.43% of the dry cell and 0.71 g/L which is the highest under high initial carbon concentration (2170 mg TOC/L) and nitrogen-unlimited conditions so far. The active biomass growth presented an asynchrony with PHA synthesis under this hydrolysate-like condition. The consortium was prior to utilize even-number carbon acid to synthesize 3-hydroxybutyrate (HB) and then the odd-number carbon acid for 3-hydroxyvalerate (HV). Fermented liquid with higher percentage of volatile fatty acids (VFAs) is favor of a higher PHA content. Non-VFAs (>30%) such as protein and carbohydrates had negative effects on PHA accumulation but facilitated the cell growth. A balance should be found between cell growth and PHA accumulation in order to achieve a relative high PHA yield.
本研究深入探讨了细菌共混物在模拟剩余污泥发酵液的基质中合成聚羟基烷酸（PHA）的动态过程。在高初始碳浓度（2170mgTOC/L）和氮不限条件下，共混物获得了 62.43%的干细胞和 0.71g/L 的最高 PHA 含量和 PHA 产率，这是迄今为止的最高水平。在这种水解产物样条件下，活性生物量的生长与 PHA 的合成呈现出不同步性。该共混物优先利用偶数碳酸合成 3-羟基丁酸（HB），然后利用奇数碳酸合成 3-羟基戊酸（HV）。挥发性脂肪酸（VFAs）比例较高的发酵液有利于获得更高的 PHA 含量。非 VFAs（>30%），如蛋白质和碳水化合物，对 PHA 积累有负面影响，但有利于细胞生长。为了获得相对较高的 PHA 产率，应在细胞生长和 PHA 积累之间找到平衡。
