Study on Biodegradation and Bioremediation of Surfactant Octylphenol Polyethoxylates

• Main Authors: Hsi-Jien Chen, 陳錫金
• Other Authors: Dyi-Hwa Tseng
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/60154712686515929439

博士 === 國立中央大學 === 環境工程研究所 === 93 === Alkylphenol polyethoxylates (APEOn) including nonylphenol polyethoxylates (NPEOn) and octylphenol polyethoxylates (OPEOn) were used very commonly in surfactants and detergents. The biodegradation metabolites of APEOn including nonylphenol (NP), octylphenol (OP), nonylphenol mono-ethoxylate (NPEO1) and octylphenol mono-ethoxylate (OPEO1) are supposed to imitate the natural hormones. The levels of these metabolites present in the environment may be sufficient to disrupt endocrine function in wildlife and humans. These compounds are more toxic and resistant to biological degradation than the parental surfactants. Therefore, the use of APEOn has been limited in many countries. Since the simpler structure of the alkyl group than NPEOn, and the OP obtain10 to 20 fold higher of the estrogenic effect than NP, the OPEOn was dealing with this study to be the target compound for the evaluation of OPEOn and its metabolites bioremediation efficiency. Five strain of OPEOn degrader which isolated from soil and sediments were evaluated in the aquatic medium using OPEOn as the sole carbon source at 30℃, 200 rpm shaking culture. The microcosms assimilated the bioremediation were employed for the evaluation of OPEOn and OP bioremediation efficiency. The exogenous strains of Pseudomonas nitroreducens TX1, Pseudomonas putida TX2, and Pseudomonas sp. OP2 were also utilized to biodegraded OPEOn and metabolites in the soil. The results of this study showed, for five strains of OPEOn degrader, strain E obtained the maximum specific growth rate of 0.46 h-1 and degradation efficiency of 95% for OPEOn primary biodegradation. Strain A can be sustained in the highest OPEOn concentration than the other four strains. The nitrogen source of (NH4)2SO4 with the concentration of 1,200 to 1,600 mg/L and pH 7 were also the feasible growth condition for the five strains in 5,000 mg/L OPEOn-MSB medium. Regarding to the bioremediation of OPEOn and OP, the exogenous degrader and soil indigenous microorganisms approved the OPEOn and metabolites biodegradation in the soil. In 91 days bioremediation period, over 98% of OPEOn and 75% of OP have been degraded in the soil. By the OP directly bioremediation process, around 25 % OP could be degraded in the soil in 70 days bioremediation period by the addition of the exogenous Pseudomonas sp. OP2. The analyzed of OPEOn biodegradation pathway in the soil was also conducted and three novel intermediates including octylcatechol, butylphenol polyethoxylates with 1-3 ethoxylate unit, and phenol had been found. The analysis of bacterial community in the soil was shown the predominant strains of Brucellaceae bacterium, Stenotrophomonas maltophilia and Aeromonas hydropila in the soil. Additionally, all three exogenous bacteria of strain TX1, TX2, and OP2 were also predominant in the soil. The bioremediation of OPEOn and its metabolites by the exogenous strains were therefore noted in this research.