表面活性剂对有机污染物污染的环境有增效修复作用.本文通过考察鼠李糖脂、蔗糖脂肪酸酯和茶皂素对BDE-209的增溶作用、对菌J-1生长的影响及菌J-1对表面活性剂的利用,研究了3种表面活性剂对菌J-1降解BDE-209的影响及机理.结果表明:3种表面活性剂对BDE-209的增溶能力大小为鼠李糖脂〉蔗糖脂肪酸酯〉茶皂素.低浓度鼠李糖脂(〈100mg·L-1)、蔗糖脂肪酸酯(〈50mg·L-1)和茶皂素(〈50mg·L-1)都能促进J-1对BDE-209的降解,且促进作用随表面活性剂浓度增加而增强,最高分别可将BDE-209降解率提高23.18%,16.47%和12.64%.3种表面活性剂中、高浓度均对J-1降解BDE-209有抑制作用,当鼠李糖脂、蔗糖脂肪酸酯和茶皂素浓度为1000mg·L-1时,J-1对BDE-209的降解率分别降低35.32%、16.54%和27.76%.低浓度表面活性剂的促进作用是增溶和协同代谢的综合效应;中等浓度的蔗糖脂肪酸酯(200~700mg·L-1)和茶皂素(100~200mg·L-1)的抑制作用是由于底物竞争或(/和)表面活性剂胶束内裹BDE-209阻碍了菌J-1与其接触所致;而高浓度表面活性剂的抑制作用是由于表面活性剂对菌J-1的毒害所致.
Surfactants are effective in enhancing remediation of organic pollutant-polluted environments.We investigated the effect and mechanism of three surfactants-rhamnolipid,sucrose fatty acid ester and tea saponin-on BDE-209 degradation by Bacillus thuringiensis J-1.In the work,the effects of surfactants on solubilization of BDE-209,growth of J-1 and the utilization of the surfactants by J-1 were observed.The results showed that solubilization of the three surfactants were in the following order:rhamnolipid sucrose fatty acid estertea saponin.Low concentration rhamnolipid (100 mg·L-1),sucrose fatty acid ester (50 mg·L-1) and tea saponin (50 mg·L-1) could enhance the degradation of BDE-209 by J-1 and the degradation efficiency increased with surfactant concentration.The highest efficiencies were increased by 23.18%,16.47% and 12.64%,respectively,compared to the control??.Medium to high concentrations of surfactants inhibited the degradation of BDE-209 by J-1.The degradation efficiencies of BDE-209 were respectively reduced by 35.32%、16.54% and 27.76% when the concentrations of these three surfactants were 1000 mg·L-1.The improved degradation of BDE-209 by surfactants at low concentration was due to solubilization and synergic metabolism with J-1.The medium concentration sucrose fatty acid ester (200~700 mg·L-1) and tea saponin (100~200 mg·L-1) inhibited the degradation of BDE-209,because they were preferentially utilized by J-1 or/and at this concentration BDE-209 was wrapped inside the surfactant micelle,making it inaccessible to the microorganism.At high concentrations,the surfactants were toxic to J-1,which reduced the degradation of BDE-209.