以硫菌提昇快速堆肥系統及土壤/水相系統中多環芳香烴之生物降解

Abstract

多環芳香烴 (Polycyclic aromatic hydrocarbons, PAHs) 為環境中普遍存在的一種污 染物，主要來源於原油的溢出、煤礦以及石化燃料不完全的燃燒所衍生的副產物。由於 其疏水性及抗分解性等本質所以極易吸附及沉積在土壤顆粒上。也因為它的普遍分佈、 毒性、致突變能力及致癌性等特性，已對人類健康造成嚴重的威脅，因而必須加以重視。 許多的研究證實微生物在好氧及厭氧的條件下具有分解多環芳香烴的能力，使得生物復 育法 (Bioremediation) 已成為處理受多環芳香烴污染土壤的主軸。然而微生物對分解多 環芳香烴的能力隨著菌種而異，因此，為提升多環芳香烴污染土壤生物復育之成效，必 須發展以特定菌種 (如硫菌) 作為優勢菌的技術來縮短生物復育時程。 本研究之主要目的是以硫化菌來提昇多環芳香烴之生物降解。首先是研究以高溫硫 氧化菌(Thermophilic Sulfur-oxidizing bacteria, SOB) 作為優勢菌種分解堆肥系統中多環芳香 烴之潛勢並且嘗試以快速堆肥程序 (High-rate composting) 縮短生物降解所需之時間。第 二階段之是以硫氧化菌與硫酸還原菌 (Sulfate-reducing bacteria) 為優勢菌種探討界面活性 劑提昇土壤/水相系統中多環芳香烴生物降解之研究。第三階段研究是以螢光原位雜交法 (Fluorescent in situ hybridization, FISH) 及聚合.鏈反應-變性梯度膠體電泳法 (PCR-DGGE) 分析硫化菌之菌數與菌相。

Polycyclic aromatic hydrocarbons (PAHs) are common environmental contaminants that are mainly derived from oil spills, coal processing, and incomplete combustion of petroleum fuels. Soils are a major environmental sink for PAHs because of their hydrophobic nature and recalcitrance. PAHs have become a major public health concern because of their ubiquitous distribution and toxic, mutagenic, and carcinogenic properties. With recent reports, on the capability of bacteria to biodegrade PAHs under various redox conditions, bioremediation had become a very promising concept for the treatment of PAH-contaminated soil. The ability of microorganisms to degrade PAHs, however, varies depending on the strain. To enhance the bioremediation of PAH-contaminated soils, the developments of bioremediation technique using specific microorganisms i.e. sulfur bacteria as dominant species are therefore necessary to shorten the time required for remediation procedures. The main goal of the study is to use of sulfur bacteria for enhancing biodegradation of PAHs. The first study is to investigate the potential of thermophilic sulfur-oxidizing bacteria (SOB) as a dominant species to degrade PAH in composting system and the time required for PAH biodegradation will be made an attempt to shorten by means of high-rate composting process. The second study is to examine surfactant-enhanced biodegradation of PAHs in soil-aqueous system by using SOB and sulfate-reducing bacteria (SRB). The third study will be experimented to characterize the microbial population of sulfur bacteria by fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR) techniques.