活性污泥微生物驯化合成聚羟基脂肪酸酯

发布时间：2018-04-27 07:12

本文选题：活性污泥 + 驯化　；参考：《济南大学》2015年硕士论文

【摘要】：聚羟基脂肪酸酯(PHA)是一种有广阔前景的生物可降解塑料,在“白色污染”日益加剧和废水处理成本不断提高的今天,研究利用活性污泥和废水生产PHA,具有非常重要的现实意义和研究价值。本文利用环氧丙烷皂化废水驯化活性污泥合成PHA,实验证明环氧丙烷皂化废水的活性污泥菌群能够合成PHA,并鉴定PHA主要单体为3-羟基丁酸(3HB)和3-羟基戊酸(3HV),且两者比例约为10:3。但发现活性污泥中的PHA成分仅占污泥干重的0.0350%,为进一步提高活性污泥产量,本文设计了通过活性污泥驯化的方法。组装驯化SBR设备,并成功运用在探究外加碳源过程中,分批小试分别添加乙酸、丙酸和丁酸为碳源,各碳源产率最大值分别为0.745g/L,0.462g/L,0.525g/L,发现添加乙酸结果最佳,选取乙酸为最终驯化的外加碳源。确定乙酸的液相检测方法,并绘制相应标准曲线。连续驯化过程周期共37天,在每个周期投加由乙酸和皂化废水配置的培养基,定期间隔取样,并在典型周期内进行连续取样。通过活性污泥微生物驯化,PHA的产率最大可达到污泥干重的23.67%,较驯化前0.0350%有较大提高。通过对典型驯化周期内各参数监测,PHA的单体成分以3HV为主,3HV:3HB比例约为19:1,较驯化前有显著提高,说明添加碳源对PHA单体组成有重要影响;同时监测典型周期内的COD、乙酸均呈下降趋势。本文通过在皂化废水中添加乙酸驯化产PHA,为利用污泥水解酸化产物合成PHA奠定了研究基础。为探究驯化使PHA产量增加的内在机制,本文进行了驯化前后污泥样本的生态学分析,发掘其中可能的PHA生产优势菌属。门水平分析,发现变形菌门在驯化前后都是活性污泥群落的优势微生物,并且该种群的比例在驯化后提高了5.73%;厚壁菌门的比例由1.90%提高到10.58%,很可能该门中的微生物与PHA合成有紧密联系。属水平分析,红杆菌属(Rhodobacteraceae)驯化后其比例增长了12.52%,占菌落总数的27.33%;芽孢杆菌属(Bacillus)驯化后其数量增长了9.43%,占菌落总数的9.61%;驯化前后根瘤菌属(Rhizobium sp.)比例基本维持在2.50%左右;这些属的微生物可能具有合成PHA的能力。未来深入研究PO皂化废水活性污泥利用污泥水解酸化产物合成PHA,将为综合利用工业废水剩余污泥开辟一条新的途径。
[Abstract]:Polyhydroxyfatty acid ester (PHA) is a kind of biodegradable plastics with broad prospects. Today, "white pollution" is increasing and the cost of wastewater treatment is increasing. It is of great practical significance and research value to study the production of PHA from activated sludge and wastewater. PHAs were synthesized from activated sludge acclimated from propylene oxide saponification wastewater. The results showed that the activated sludge flora of propylene oxide saponification wastewater could synthesize PHA, and the main monomers of PHA were identified as 3-hydroxybutyrate (3HBb) and 3-hydroxyvalerate (3HVH), and the ratio of the two was about 10: 3:. However, the PHA in activated sludge is only 0.0350% of the dry weight of sludge. In order to further increase the production of activated sludge, a method of acclimation by activated sludge is designed. The SBR equipment was assembled and domesticated, and successfully used in the process of exploring external carbon sources. Acetic acid, propionic acid and butyric acid were added as carbon sources respectively in small batches. The maximum yield of each carbon source was 0.745 g / L 0.462g / L ~ (-1) 0. 525g / L respectively. The results of adding acetic acid were found to be the best. Acetic acid was selected as the final domesticated carbon source. The liquid phase detection method of acetic acid was determined and the corresponding standard curve was drawn. The period of continuous acclimation was 37 days. Each cycle was supplemented with acetic acid and saponification wastewater, and samples were sampled periodically and continuously during typical periods. The maximum yield of PHA through microbial acclimation of activated sludge can reach 23.67% of the dry weight of sludge, which is higher than that of 0.0350% before acclimation. The ratio of 3HV to 3HV3HB was 19: 1, which was significantly higher than that before acclimation, indicating that the addition of carbon source had an important effect on the composition of PHA monomer. At the same time, there was a decreasing trend of acetic acid in the typical cycle. In this paper, acetic acid was added to the saponification wastewater to produce PHAs, which laid a foundation for the synthesis of PHA from sludge hydrolytic acidification products. In order to explore the internal mechanism of PHA production increase after acclimation, the ecological analysis of sludge samples before and after acclimation was carried out to find out the possible dominant genus of PHA production. Gate level analysis showed that Proteus was the dominant microorganism in activated sludge community before and after acclimation. The proportion of this population increased by 5.73% after acclimation, and the proportion of phylum thuringiensis increased from 1.90% to 10.58%. It is very likely that the microbes in the phylum are closely related to the synthesis of PHA. The proportion of Rhodobacteraceae increased 12.52%, accounting for 27.33% of the total number of colonies after acclimation. After acclimation, the number of Rhodobacteraceae increased 9.43%, accounting for 9.61% of the total number of colonies, and Rhizobium sp.before and after acclimation.) The ratio is about 2.50%, and the microbes of these genera may have the ability to synthesize PHA. In the future, the synthesis of PHAs from activated sludge of PO saponification wastewater by hydrolysis and acidification of sludge will open up a new way for comprehensive utilization of surplus sludge from industrial wastewater.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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