【作者】 罗翠；

【导师】 李茵；

【作者基本信息】 东华大学 ， 环境工程， 2008， 硕士

【摘要】 在废水生物处理中,微生物对废水中污染物质的降解和转化都是在酶的催化作用下进行的一系列复杂的生化反应过程,因此研究废水处理系统中微生物酶活性及其作用对于深入反应系统机理,提高废水处理效率等有着十分重要的意义。为研究酶的活性分布,环境因素对酶活性的影响,氮盐、磷盐对酶活性的影响,酶的活性与出水水质的关系以及各种酶活性的变化,本课题选取β-葡萄糖苷酶、碱性磷酸酶、亮氨酸氨基肽酶和脂肪酶四种水解胞外酶作为研究对象,对厌氧-缺氧-好氧废水生物处理系统中上述酶的活性作了较为深入的研究。分析酶的活性分布试验表明,绝大部分胞外酶是与细胞相连或固定在细胞外多聚基质里,而不是被微生物以自由、溶解状态释放到溶液中。通过环境因素对酶的影响的研究得,β-葡萄糖苷酶、碱性磷酸酶、亮氨酸氨基肽酶和脂肪酶在60℃有最高酶活;偏碱性条件(pH=8～9)有利于酶促反应的进行;酶活随底物浓度的增加而增大;通常抑制剂含量越大其抑制作用越强,但对各待测酶的抑制效果不尽相同;β-葡萄糖苷酶、亮氨酸氨基肽酶和脂肪酶在抑制剂存在下24h内活性下降最多,而磷酸酶却较稳定,其活性几乎不受抑制剂作用时间的影响。超声波对酶促反应起加速作用,在超声作用功率为0W-480W的范围内,待测四种胞外水解酶的活性都随超声功率的增强而升高,在超声作用时间为0～10min的时间内,酶活性随时间持续增强。对氮、磷对酶活性的影响研究发现,对于β-葡萄糖苷酶和脂肪酶,较高浓度的NO2-、NO3-和PO43-(浓度大于100mg/L)有助于提高酶的活性;对于碱性磷酸酶,NO2的存在抑制了碱性磷酸酶的活性,NO3-对碱性磷酸酶的活性起激活作用,较高浓度的PO43-能够提高酶促反应速度,增大酶的活性;对于亮氨酸氨基肽酶,较低浓度的NO2-、NO3和PO43-(浓度小于100mg/L)有利于酶活性的发挥。由此得出控制相关作用条件可最大限度地发挥酶的作用性能,提高微生物活性。对酶的活性分析还发现,酶活性可以有效地反映微生物的活性,可考虑用其代替MLSS、MLVSS或VSS/SS来表征微生物活性。β-葡萄糖苷酶和脂酶的活性直接影响COD和TOC的去除,β-葡萄糖苷酶的活性大小及其水解作用对废水中有机物的降解以及系统COD去除性能至关重要。碱性磷酸酶活性越大,总磷的去除率越高,反之亦然。碱性磷酸酶的活性与总磷去除率表现出了显著的相关性。亮氨酸氨基肽酶的活性都随氨氮和总氮去除率的提高而增大。各反应池中相对稳定的碱性磷酸酶、亮氨酸氨基肽酶和脂酶的活性大小说明系统中酶的消耗与合成达到了一个动态平衡。更多还原

【Abstract】 Microbial degradation and transformation of pollutants in wastewater are a series of complicated biochemical reaction process as conducted by enzyme. It is significant that study on enzymatic activities in wastewater biotreatment system contributes to going deep into reaction mechanism and improving removal efficiency. In order to kown the distribution of enzymatic activities, the environmental factors and NO₂^-, NO₄^-, PO₄^3- effect on enzymes, the relation between enzymatic activities and treated water quality and comparation of enzymatic activities, four extracellular hydrolysis enzymes were selected in this study, i. eβ-glucosidase, alkaline phosphatase, leucine-aminopeptidase and lipase, to investigate their activities and action in an anaerobic-anoxic-aerobic system.The study on the distribution of enzymatic activities showed that most of extracellular enzymes were associated with cells or immobilized in extracellular polymeric substrates, rather than releasing to the solution as a free, soluble state. The environmental factors effect on enzymes study showed the highest enzymatic activity appeared at 60℃. Enzymatic activities were accelerated under alkaline condition （pH=8-9） and increased with increase of substrate concentration. Higher inhibitor concentration induced to a better prohibitive effect, but inhibitory effect was different for each enzyme. Inhibitor decreased the enzymatic activities ofβ-glucosidase, leucine-aminopeptidase and lipase after 24 hours. However, the activity of alkaline phosphatase was observed to be quite stable. Ultrasonic irradiation accelerated the enzymatic catalys. Enzymatic activities increased with increase of ultrasonic power within 0-480W, and increased with increase of ultrasonic process time within 0-10min. The study on enzymatic stability found that forβ-glucosidase and lipase, a higher NO₂^-, NO₃^- and PO₄^3- concentration （more than 100mg/L） conduced to increase enzymatic activities. For alkaline phosphatase, NO₂^- inhibited its activity, but NO₃^- advanced its activity, high PO₄^3- concentration （more than 100mg/L） increased enzymatic activity. For leucine-aminopeptidase, low concentration of NO₂^-, NO₃^- and PO₄^3- （less than 100mg/L） resulted in increases of enzymatic activities. Thus, high enzymatic activities were expected to obtain through controlling the related conditions.The study on enzymatic activities showed that, the enzymatic activities could be as an indicator to reflect the microbial activity instead of MLSS, MLVSS and VSS/SS. The enzymatic activity ofβ-glucosidase and lipase were correlated with COD, TOC removal, and organic compound degradation in the system. A higher alkaline phosphatase activity, a higher TP removal was obtained, vice versa. Alkaline phosphatase activity was related to TP removal notably. Similar to alkaline phosphatase, higher leucine-aminopeptidase activity, higher NH₃-N and TN removal was obtained, vice versa. The stable alkaline phosphatase, leucine-aminopeptidase and lipase activities were found in each reactor could be proposed that an equilibration existed between enzyme consumption and production at steady state.更多还原