一株2氯酚优势降解菌的生物降解机理.doc

籃蜮工學陡 本科毕业论文 一株2■翱分OOS的生物醐 专 业 生物工程 班 级 B生物102 学 号 1010307227 学生姓名 张蓉 指导教师 李朝霞 完成日期 2014年6月5日 一株2-氯酚优势降解菌的生物降解机理 取木实验室保藏的一株2-氯酚优势降解菌LF1-4至牛肉膏蛋白胨培养基上 连续活化2次，用无菌去离子水洗卜*并稀释成约108cfu/mL的菌悬液。按10%接种量 接种于含宥100 mg/L 2-氯酚为唯一碳源的无机盐培养基中进行避光发酵，分别测定 培养溫度和pH两种主耍影响因素卜的2-氯酚的降解率，从而获得较适宜的降解条件。 在此适宜的条件不，定时取样，分别用气相色谱仪测定2-氯酚浓度、用气-质联用仪 检测底物减少和产物生成的过程以及用氯离子选择性电极法测定氯离子浓度，确定 氯酚生物降解机制。 结來表明，优势降解菌LF1-4的适宜培养温度和pll是35 C和pH8. 0。气相色谱 显示2-氯酚的浓度随时间有规律的减少，此结來与气-质联用仪测定的底物的减少过 程一致，中间产物生成呈先增加石减少而终产物呈逐渐增加趋势。氯离子浓度不断增 加，增加的速度从慢到快最盾趋于平稳，且其浓度的增加明显滞盾于2-氯酚浓度的 减少，由此可推出2-氯酚的生物降解机制是先开环，盾脱氯。 关键词：2-氯酚；优势降解菌；氯离子；生物降解机理 Biological degradation mechanism of a dominantdegradation strain on 2-chlorophenol Abstract： A dominant degradation bacteria strain LF1-4 on 2-chlorophenol preserved in our lab was twicely activated on the beef extract peptone medium and diluted to approximately 108 cfu/mL of bacteria suspension with the sterile deionized water. With inoculation amount 10%，the bacteria suspension was dark fermentated in the mineral medium(MM) with 100 mg/L 2- chlorophenol as exclusive carbohydrate. The degradation rate of 2-chlorophenol under two main factors on the culture temperature and pH were measured to obtain more appropriate degradation conditions. Under the appropriate conditions，with timing sampling，the biodegradation mechanisms on 2-chlorophenol was analyed with 2-chlorophenol concentrations determined by gas chromatography (GC)， reducion of the substrate and generation of the product determined by gas chromatography -mass spectrometer (GC-MS)，and chloride ion concentration determined by chlorine ion selective electrode. The results show that suitable culture temperature and pH of the advantage degrading strain LF1-4 were 35 °C and pH8.0. The concentration of 2-chlorophenol reduced regularly over time determinated by GC，which is consistented with the reduction process of the substrate determinated by GC-MS. Intermediate product was first increased and then decreased while the final product was gradually i