摘要
利用序批式反应器,以乙酸钠为碳源驯化活性污泥,选择和富集具有积累聚羟基链烷酸酯(PHAs)能力的微生物菌群,探究不同的碳源条件对PHAs合成产率、单体(PHB、PHV)组成的影响,寻求PHAs总量和PHAs单体产率最高的碳源组成和类型;考察影响剩余污泥合成PHAs的因素,重点调控p H、碳氮比条件,实现剩余污泥贮存PHAs的工艺优化。实验结果表明,在微好氧循环体系中,相对于丙酸、丁酸等单一有机酸为碳源的培养条件,乙酸为单一碳源时可获得最高的PHAs合成量,达到了0.234mg/mg,其中PHB的产率为0.225mg/mg,占96%。;不同比例的乙酸-丙酸和丁酸-丙酸等混合酸的合成条件下,以乙酸/丙酸=1:2的混合酸作为碳源时,单位质量干重污泥PHAs的产率可达到为0.384mg/mg;对比C/N分别为20、100、500的培养条件,当C/N=500时剩余污泥贮存PHAs的能力较强,最高产率约为0.356mg/mg;分别控制p H=5、p H=7、p H=9的酸度条件,则中性环境更有利于剩余污泥贮存,可达0.39mg/mg的PHAs。
Microorganisms having the ability of synthesizing polyhydroxyalkanoates are selected from activated sludge which is cultivated in the sequencing batch reactor providing single carbon sources(acetate).The type and mixture ratio of carbon source contributing to microorganisms accumulating more polyhydroxyalkanoates will be explored.In the end, The optimal process conditions respecting p H and ratio of carbon source and nitrogen source will be further dominated to implement the highest production of PHAs.The experimental results showed that, the highest production of PHAs,up to 0.23 mg/mg,can be obtained when the acetic acid rather than the propionic acid and butyric acid as the sole carbon source in the micro aerobic recycling system. When the ratio of the acetic acid and propionic acid is one to two, the mixed acid can provide organic most appropriate carbon source to accumulate PHAs. The ability of organic storage PHAs can reach 0.384mg/mg. Comparing to 20 and 100, when the ratio of Carbon source and nitrogen source is 500, the average yield of PHAs can be reached up to 0.356mg/mg.The research about different acidity condition pointed that,the residual sludge in the neutral environment will synthetize 0.39mg/mg PHAs.
引文
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