【作者】 杨素亮；

【导师】 胡宗定； 闻建平；

【作者基本信息】 天津大学 ， 生物化工， 2005， 硕士

【摘要】 苯酚及酚类化合物是一种常见的工业污染物,广泛存在于炼油、化工、合成纤维、印染和双酚A等行业的工业废水中。苯酚是一种生物毒性物质,即使在低浓度下对人体及微生物也有毒害作用。国际卫生组织规定饮用水中苯酚浓度应低于1μg/L。近些年来,随着我国工农业的迅速发展,未经处理的含酚废水对人类的生存环境已经造成了严重的威胁。生物法处理含酚工业废水是近些年来发展起来的一项含酚废水处理技术,该方法具有处理成本低、二次污染小等优点。到目前为止,已经分离和鉴定出许多好氧微生物可以利用苯酚作为唯一碳源和能源。本研究利用传统微生物方法,从天津市煤气总公司活性污泥中筛选到一株高效苯酚降解菌,可利用苯酚作为唯一碳源和能源。并经中国农业微生物菌种保藏管理中心（ACCC）鉴定为热带假丝酵母（Candida tropicalis）。通过对该菌株在不同温度、pH值,以及不同苯酚浓度下的生长和苯酚降解情况的考察,确定了该菌株的最适生长温度为30℃,最适pH值为6.0,最大可降解苯酚浓度为2000 mg/L。当前发酵工业和其它微生物生产部门所使用的高产菌株,绝大多数都是使用诱变育种技术来提高其活性。为进一步提高菌株的苯酚降解能力,本研究对所得菌株进行了He-Ne激光诱变育种研究,经过多次诱变,在大量的突变株中筛选到了一株高效苯酚降解菌株CTM2,该菌株具有良好的遗传稳定性。与野生型菌株相比,CTM2的降酚能力得到明显提高。野生型热带假丝酵母经激光辅照后,降酚能力由诱变前的2000 mg/L提高到2600 mg/L;同样降解2000mg/L的苯酚,降解时间也由66 hr缩短到54.5 hr。野生型菌株的Haldane细胞生长动力学参数为μmax = 0.48 h^-1,KS = 11.71mg/L, Ki = 207.88 mg/L,其相应的苯酚降解动力学参数为A=0.8227,B=0.2765h^-1。突变株CTM2的Haldane细胞生长动力学参数为μmax= 0.54 h^-1,KS = 6.70mg/L,K i= 234.25 mg/L,其相应的底物降解动力学参数为A=0.8784,B=0.2981h^-1。更多还原

【Abstract】 Phenol is present in the wastewater of many industries, including coke petroleum,pulp and paper, pharmaceutical, wood processing chemicals and paint solvent. Phenol,even low concentration, does harm to biomass for its toxic properties. With theprocess of economic, wastewater containing phenol has greatly thretoned environment.Because lots of aerobic microorganisms can utilize phenol as sole carbon, biologicalmethods of phenol removal are preferable in wastewater treatment process as arelatively low processing costs and low possibility of a secondary pollution.In our study, a strain of Candida tropicalis with high efficient phenol-degradingbacteria was isolated from acclimated activated sludge, and was identified as amember of Candida by the Chinese Academy of Agricultural Sciences.The phenol degradation was studied under the conditions of different centigrade,pH and initial phenol concentration. The results showed that 30℃ and pH 7.0 werethe optimal growth conditions. Furthermore, 2000 mg/l phenol could be entirelydegraded within 66 hrs.In order to enhance phenol degradation potential of Candida tropicalis, He-Nelaser irradiation was applied in our studies. And the mutant CTM2 was obtained. Thetests of phenol degradation demonstrated that CTM2 owned the higher phenoldegradation potential than its parent strain, and stable heredity.In contrast with wild type strain, phenol degradation potential of CTM2 wasobviously increased, which could degrade the phenol of 2600 mg/l within 84 hrs.The kinetics of cell growth and phenol biodegradation of CTM2 was investigated.Haldane’s equation was adopted to describe the growth kinetics of CTM2 at 30℃ andpH=6.0: μ_X = 0.54 C_S /（6.70 + C S +C²_S/ 234.25）. The phenol degradation processwas associated to the cell growth kinetics: μ_S = 0.8784 μ_X +0.2981h^-1. It wasindicated that the results simulated by the model agreed well with the experimentaldata. Higher values of the specific growth and degradation rates further demonstratedthe superiority of CTM2 for phenol degradation.更多还原