Quantification of Sulfur-Oxidizing Bacteria in Thermophilic Sludge Bioleaching by Real-Time PCR

• Main Authors: Li-Chieh Chou, 周俐潔
• Other Authors: Shen-Yi Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/32466557311794870398

碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程所 === 98 === Heavy metals can be removed from the sludge using bioleaching technologies at thermophilic acondition and thereby providing an option for biotreatment of wasted sludge generating wastewater treatmnet. The purposes of this study were to establish a molecular biotechnology technique, real-time PCR, to monitor the bacterial numbers of the sulfur-oxidizing bacteria during the sludge thermophilic bioleaching. The 16S rDNA gene was targeted for real-time PCR quantification of three bioleaching bacteria: Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, Acidithiobacillus caldus. Existing primers for monitoring thremophilic sulfur-oxidizing bacteria and new primers (DQ-F/DQ-R) specially designed for Sulfobacillus thermosulfidooxidans were used. The specificity and stringency for thremophilic sulfur-oxidizing bacteria were tested before its experiments on monitoring the bacterial community, bacterial number during the sludge thermophilic bioleachng and the future application on testing various environmental samples. The results showed that the importance of DNA quality, especially when working with DNA extracted from sludge samples obtained from the thermophilic bioleaching process. In the sludge bioleaching experiment, the total number of bacteria decreased slightly. Sulfobacillus acidophilus was identified as the dominant biooxidizing bacterium, while Sulfobacillus thermosulfidooxidans occurred in significantly lower numbers. The total number of these three oxidizing bacteria increased during the thermophilc bioleaching process. Additionally, these three thermophilic sulfur-oxidizing bacteria accounted for 73-89% of total bacteria at the end of the bioleaching experiment. Meanwhile, the decrease of pH, production of sulfate, degradation of SS/VSS and solubilization of heavy metal were found to have significant relationship with these three thermophilic sulfur-oxidizing bacteria during the bioleachng process. Overall, the real-time PCR is considered to be suitable methods to monitor numbers of thermophilic sulfur-oxidizing bacteria during the bioleaching process.