Impacts of heavy metals Zn invasion on enzymatic kinetic reaction of polyphosphate accumulation organisms under short-term temperature conditions

• Main Authors: Yi-Ling Tsai, 蔡易玲
• Other Authors: Yung-Pin Tsai
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/06695478156187888238

碩士 === 國立暨南國際大學 === 土木工程學系 === 97 === This study mainly investigated the effects of Zinc metal ion and concentration(0～4mgl-1) on the phosphorus removal mechanisms , including phosphorus release/uptake, polyhydroxyalkanoates (PHAs) synthesis/degradation, and total intercellular Acetyl CoA Synthase activity and Polyphosphate Kinase activity of the activated sludge under short-term temperature condition. The performance of B-SBR activated sludge, which was acclimated until steady state basing on the condition of sludge retention time (SRT) 10 days , maintained the removal raties of COD and PO43- above 90 %. In order to realize the operational strategy for EBPR system under metal invasion situation, the performances of batch experiments of phosphate release and uptake, PHAs synthesis/degradation, and total intercellular Acetyl CoA Synthase activity and Polyphosphate Kinase activity were used as indicators to investigate the effects of heavy metal zinc on phosphate removal mechanisms and toxic inhibition of microorganisms under different metal concentration (0～4mgl-1) and temperature conditions(10℃～30℃). In addition, inhibitory type about Acetyl CoA Synthase inhibited by zinc was mixed non-competitive inhibition, while the Polyphosphate Kinase inhibition type was competitive inhibition. Results of batch experiments under the condition of without any metal addition showed that specific substrate utilization rate (SSUR), specific phosphorus release/uptake rates(SPRR,SPUR), PHAs synthesis/degradation rates, and total intercellular Acetyl CoA Synthase and Polyphosphate Kinase activities of microorganisms had the best tolerant ability to zinc invasion under 20℃, In addition , the temperature order of the tolerant ability of microorganisms to heavy metal invasion was 20℃＞30℃＞10℃, It was also found in the study that, the microorganism intercellular Acetyl CoA Synthase Enzyme activity was inhibited by zinc metal toxicity, it resulted in microbial synthesis of PHAs slowed down and insufficient PHA and total intercellular Acetyl CoA Enzyme activity were provided for phosphorus uptake in aerobic stage , In addition, the existence of metal zinc also influenced the decomposition of PHAs in aerobic phase. At the same time, the phosphate removal ability was further deteriorated due to the insufficient of intercellular carbohydrate and external toxic inhibition. Thus, it could be known that the increase or decrease of PHAs and Acetyl CoA Synthase activity intercellular carbohydrate metabolism were influenced and impacted by each other in both anaerobic and aerobic phase, In the other hand, The Polyphosphate Kinase directly impacted on the phosphorus uptake in the aerobic phase.