采用富集培养法从喷施拟除虫菊酯类农药的菜园土壤中,分离得到一株能降解氰戊菊酯的细菌BFE-023。经生理生化和16S r DNA序列分析,将菌株BFE-023鉴定为地衣芽孢杆菌(Bacillus licheniformis)。应用Plackett-Burman实验设计确定了影响该...采用富集培养法从喷施拟除虫菊酯类农药的菜园土壤中,分离得到一株能降解氰戊菊酯的细菌BFE-023。经生理生化和16S r DNA序列分析,将菌株BFE-023鉴定为地衣芽孢杆菌(Bacillus licheniformis)。应用Plackett-Burman实验设计确定了影响该菌株降解氰戊菊酯的主要影响因素,利用响应面分析法优化了其降解条件。在优化条件下,研究菌株BFE-023对氰戊菊酯的降解过程及其中间产物3-苯氧基苯甲酸(3-PBA)的生成规律。结果表明,培养时间和降解体系中氰戊菊酯浓度及氯化铁含量是影响其降解的主要因素,优化条件下60 h内对氰戊菊酯降解率可达到88.71%,与所建立的模型预测值(88.78%)相吻合。菌株BEF-023降解氰戊菊酯的过程中,降解中间产物3-PBA的生成量呈现先明显增加后逐渐减少的趋势,说明菌株BEF-023可能具备继续降解中间产物3-PBA的能力。展开更多
A promising strategy to counteract the progressing plastic pollution of the environment can involve the replacement of persistent plastics with biodegradable materials.Biodegradable polymers are enzymatically degradab...A promising strategy to counteract the progressing plastic pollution of the environment can involve the replacement of persistent plastics with biodegradable materials.Biodegradable polymers are enzymatically degradable by various hydrolytic enzymes.However,these materials can reach the environment in the same way as conventional plastics.Therefore,they are accessible to terrestrial,freshwater,and marine biota.Once ingested by marine organisms,highly active enzymes in their digestive tracts may break down biodegradable compounds.We incubated microparticles of five different biodegradable plastics,based on polylactictic acid(PLA),polybutylene succinate(PBS),polybutylene adipate terephthalate(PBAT)and polyhydroxybutyrate-co-valerate(PHBV),in-vitro with the gastric fluid of the edible crab Cancer pagurus and evaluated the hydrolysis rates by pH Stat titration.A plastic blend of PLA with PBAT showed the highest hydrolysis rate.The enzymes in the gastric fluid of crabs were separated by anion exchange chromatography.Fractions with carboxylesterase activity were identified using fluorescent methylumbelliferyl(MUF)-derivatives.Pooled fractions with high carboxylesterase activity also hydrolyzed a PLA/PBAT plastic blend.Carboxylesterases showed molecular masses of 40–45 kDa as determined by native gel electrophoresis(SDS-PAGE).Our study demonstrated that digestive carboxylesterases in the gastric fluid of C.pagurus exhibit a high potential for hydrolyzing certain biodegradable plastics.Since esterases are common in the digestive tract of organisms,it seems likely that other invertebrates possess the ability to hydrolyze biodegradable plastics.展开更多
文摘采用富集培养法从喷施拟除虫菊酯类农药的菜园土壤中,分离得到一株能降解氰戊菊酯的细菌BFE-023。经生理生化和16S r DNA序列分析,将菌株BFE-023鉴定为地衣芽孢杆菌(Bacillus licheniformis)。应用Plackett-Burman实验设计确定了影响该菌株降解氰戊菊酯的主要影响因素,利用响应面分析法优化了其降解条件。在优化条件下,研究菌株BFE-023对氰戊菊酯的降解过程及其中间产物3-苯氧基苯甲酸(3-PBA)的生成规律。结果表明,培养时间和降解体系中氰戊菊酯浓度及氯化铁含量是影响其降解的主要因素,优化条件下60 h内对氰戊菊酯降解率可达到88.71%,与所建立的模型预测值(88.78%)相吻合。菌株BEF-023降解氰戊菊酯的过程中,降解中间产物3-PBA的生成量呈现先明显增加后逐渐减少的趋势,说明菌株BEF-023可能具备继续降解中间产物3-PBA的能力。
基金This work was supported by the European Union's Horizon 2020 research and innovation program(grant agreement number 860407).
文摘A promising strategy to counteract the progressing plastic pollution of the environment can involve the replacement of persistent plastics with biodegradable materials.Biodegradable polymers are enzymatically degradable by various hydrolytic enzymes.However,these materials can reach the environment in the same way as conventional plastics.Therefore,they are accessible to terrestrial,freshwater,and marine biota.Once ingested by marine organisms,highly active enzymes in their digestive tracts may break down biodegradable compounds.We incubated microparticles of five different biodegradable plastics,based on polylactictic acid(PLA),polybutylene succinate(PBS),polybutylene adipate terephthalate(PBAT)and polyhydroxybutyrate-co-valerate(PHBV),in-vitro with the gastric fluid of the edible crab Cancer pagurus and evaluated the hydrolysis rates by pH Stat titration.A plastic blend of PLA with PBAT showed the highest hydrolysis rate.The enzymes in the gastric fluid of crabs were separated by anion exchange chromatography.Fractions with carboxylesterase activity were identified using fluorescent methylumbelliferyl(MUF)-derivatives.Pooled fractions with high carboxylesterase activity also hydrolyzed a PLA/PBAT plastic blend.Carboxylesterases showed molecular masses of 40–45 kDa as determined by native gel electrophoresis(SDS-PAGE).Our study demonstrated that digestive carboxylesterases in the gastric fluid of C.pagurus exhibit a high potential for hydrolyzing certain biodegradable plastics.Since esterases are common in the digestive tract of organisms,it seems likely that other invertebrates possess the ability to hydrolyze biodegradable plastics.
