Efficient Polyhydroxyalkanoates Production from a Waste-Activated Sludge Alkaline Fermentation Liquid by Activated Sludge Submitted to the Aerobic Feeding and Discharge Process
Efficient Polyhydroxyalkanoates Production from a Waste-Activated Sludge Alkaline Fermentation Liquid by Activated Sludge Submitted to the Aerobic Feeding and Discharge Process
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DOI：
10.1021/es9014458
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发表时间：
2009-10-15
影响因子：
11.4
通讯作者：
Zheng, Xiong
中科院分区：
文献类型：
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作者：
Jiang, Yamin;Chen, Yinguang;Zheng, Xiong
在我们先前的出版物中报道，当废物活化污泥（WAS）在pH 10.0下厌氧发酵时，短链脂肪酸（SCFA）的积累显著增强（Yuan等人，Environ. Sci. 2006，40，2025-2029）。以废碱液发酵液为碳源，采用好氧补料排放（AFD）工艺，对活性污泥法生产聚羟基脂肪酸酯（PHA）进行了研究。据观察，与文献中报道的其他PHA合成方法相比，AFD方法显示出最高的PHA产量。活性污泥经AFD工艺处理后，污泥中PHA含量达到72.9%。这是迄今为止通过使用废物作为可再生碳源的活性污泥获得的最高PHA含量。尽管氮和磷被释放到WAS碱性发酵液中，但它们的存在并不影响PHA合成，这表明不需要去除释放的氮和磷，并且发酵液可以直接用于PHA生产。积累的PHA主要由3-羟基丁酸（3 HB）（73.5 mmol C%）、3-羟基戊酸（3 HV）（24.3 mmol C%）和3-羟基-2-甲基戊酸（3 H2 MV）（2.2 mmol C%）组成。进一步研究表明，碱性发酵液中的SCFA对PHA的产生起主要作用，而蛋白质和碳水化合物对PHA的产生起主要作用。由WAS碱性发酵液产生的PHA具有8.5 × 10（5）Da的分子量和101.4 ℃的熔点。使用16 S rRNA基因克隆文库的分析显示，γ-变形菌门、α-变形菌门和β-变形菌门是PHA生产系统中的优势微生物。
It was reported in our previous publication that the accumulation of short-chain fatty acids (SCFA) was significantly enhanced when waste-activated sludge (WAS) was anaerobically fermented at pH 10.0 (Yuan, et aL, Environ. Sci. Technol. 2006, 40, 2025-2029). In this paper,the production of polyhydroxyalkanoate (PHA) by activated sludge with an aerobic feeding and discharge (AFD) process was investigated by the use of WAS alkaline fermentation liquid as the carbon source. It was observed that compared with other PHA synthesis processes reported in the literature, the AFD process showed the highest PHA production. The PHA content in sludge reached 72.9% when activated sludge was submitted to the AFD process. This was the highest PHA content obtained so far by activated sludge using wastes as the renewable carbon source, Although nitrogen and phosphorus were released into the WAS alkaline fermentation liquid, their presence did not affect PHA synthesis, which indicates that it is unnecessary to remove the released nitrogen and phosphorus, and the fermentation liquid can be used directly for PHA production. The accumulated PHA was mainly composed of 3-hydroxybutyrate (3HB) (73.5 mmol C%), 3-hydroxyvalerate (3HV) (24.3 mmol C%), and 3-hydroxy-2-methylvalerate (3H2MV) (2.2 mmol C%). Further investigation showed that SCFA rather than protein and carbohydrate in, the alkaline fermentation liquid made the main contribution to PHA production. The PHA produced from WAS alkaline fermentation liquid, had a molecular weight of 8.5 x 10(5) Da and a melting point of 101.4 degrees C. Analysis using the 16S rRNA gene clone library revealed that gamma-Proteobacteria, alpha-Protoobacteria, and beta-Proteobacteria were the dominant microorganisms in the PHA production system.