Acinetobacter sp.WML1分离自淡水湖渔场沉积物,能降解几丁质,具有一定的应用价值。为了评价菌株WML1的生物安全性,为菌株的安全使用提供参考和保障,采用常规纸片扩散法检测耐药性,用血琼脂平板划线法检测溶血性,用溴甲酚紫显色法检测...Acinetobacter sp.WML1分离自淡水湖渔场沉积物,能降解几丁质,具有一定的应用价值。为了评价菌株WML1的生物安全性,为菌株的安全使用提供参考和保障,采用常规纸片扩散法检测耐药性,用血琼脂平板划线法检测溶血性,用溴甲酚紫显色法检测氨基酸脱羧酶活性,用试剂盒测定硝酸还原酶活性。在菌株生物安全性分析的基础上,通过单因素试验法和正交试验法进行菌株WML1产几丁质酶发酵条件的优化。结果表明,菌株WML1对多种抗生素敏感,无溶血性,无硝酸还原酶活性,有精氨酸脱羧酶活性及微弱的赖氨酸和鸟氨酸脱羧酶活性;其最优产酶条件为0.4%黄豆粉、0.20%半乳糖、0.03%KH2PO4、0.07%K2HPO4、0.002%FeSO_(4)、0.05%Mg SO_(4)·7H2O、0.001%ZnSO_(4)、0.60%胶体几丁质、pH 9.5、5.0%的接种量、25 m L的装液量(对应250 m L容量瓶)、37℃的培养温度,优化后的几丁质酶活为(2.72±0.09)U/m L。综上所述,不动杆菌WML1在使用安全性上危害较小,可防可控,经发酵条件优化后其所产几丁质酶的活性提高了约4.61倍,为产几丁质酶菌株的工业化应用提供了理论基础。展开更多
A new phenol-degrading bacterium with high biodegradation activity and high tolerance of phenol, strain PD 12, was isolated from the activated sludge of Tianjin Jizhuangzi Wastewater Treatment Facility in China. This ...A new phenol-degrading bacterium with high biodegradation activity and high tolerance of phenol, strain PD 12, was isolated from the activated sludge of Tianjin Jizhuangzi Wastewater Treatment Facility in China. This strain was capable of removing 500 mg phenol/L in liquid minimal medium by 99.6% within 9 h and metabolizing phenol at concentrations up to 1100 mg/L. DNA sequencing and homologous analysis of 16S rRNA gene identified PD12 to be an Acinetobacter sp. Polyvinyl alcohol （PVA） was used as a gel matrix to immobilize Acinetobacter sp. strain PDI2 by repeated freezing and thawing. The factors affecting phenol degradation of immobilized cells were investigated, and the results showed that the immobilized cells could tolerate a high phenol level and protected the bacteria against changes in temperature and pH. Storage stability and reusability tests revealed that the phenol degradation functions of immobilized cells were stable after reuse for 50 times or storing at 4℃ for 50 d. These results indicate that immobilized Acinetobacter sp. strain PD 12 possesses a good application potential in the treatment of phenol-containing wastewater.展开更多
提出一种新的方法,用于富集苯并[a]芘耐受菌株。该方法使用多孔介质脱脂棉作为载体,从连续流动的流体——下水道污水中富集菌株。利用介质截留法、富集培养法等理论,为富集目标微生物提供了最佳条件。以苯并[a]芘为唯一碳源和能源,从下...提出一种新的方法,用于富集苯并[a]芘耐受菌株。该方法使用多孔介质脱脂棉作为载体,从连续流动的流体——下水道污水中富集菌株。利用介质截留法、富集培养法等理论,为富集目标微生物提供了最佳条件。以苯并[a]芘为唯一碳源和能源,从下水道沉积物中分离、筛选出4株苯并[a]芘耐受菌株,其中一株能在20天内将40 mg/L的苯并[a]芘降解28.7%。通过16S r RNA基因序列分析和部分生理生化特征分析,鉴定该菌株为Acinetobacter sp.Bap30。这是不动杆菌可降解苯并[a]芘的首次报道。添加其他碳源和低分子量多环芳烃——菲作为共代谢底物,研究菌株的共代谢作用。研究结果对石油污染的土壤或者焦化废水等工业污水中的高分子量多环芳烃——苯并[a]芘具有非常重要的实践意义。展开更多
Objective To purify a low-temperature hydroxylamine oxidase （HAO） from a heterotrophic nitrifying bacterium Acinetobacter sp. Y26 and investigate the enzyme property. Methods A HAO was purified by an anion-exchange ...Objective To purify a low-temperature hydroxylamine oxidase （HAO） from a heterotrophic nitrifying bacterium Acinetobacter sp. Y26 and investigate the enzyme property. Methods A HAO was purified by an anion-exchange and gel-filtration chromatography from strain Y16. The purity and molecular mass were determined by RP-HPLC and SDS-PAGE. The HAO activity was detected by monitoring the reduction of potassium ferricyanide using hydroxylamine as substrate and ferricyanide as electron acceptor. The partial amino acid sequence was determined by mass spectrometry. Results The low-temperature HAO with a molecular mass of 61 kDa was purified from strain Y26 by an anion-exchange and gel-filtration chromatography. The enzyme exhibited an ability to oxidize hydroxylamine in wide temperature range （4-40 ℃） in vitro using hydroxylamine as substrate and ferricyanide as electron acceptor. It was stable in the temperature range of 4 to 25 ℃ and pH range of 6.0 to 8.5 with less than 30% change in its activity. The optimal temperature and pH were 15 ℃ and 7.5, respectively. Three peptides were determined by mass spectrometry which were shown to be not identical to other reported HAOs. Conclusion This is the first study to purify a low-temperature HAO from a heterotrophic nitrifier Acinetobecter sp. It differs from other reported HAOs in molecular mass and enzyme properties. The findings of the present study have suggested that the strain Y26 passes through a hydroxylamine-oxidizing process catalyzed by a low-temperature HAO for ammonium removal.展开更多
A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological an...A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological and biochemical properties and analysis of 16S rRNA gene sequence,it was preliminarily identified belonging to the genus Acinetobacter.The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate(DINP) .The degradation tests using diethyl phthalate(DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp.JDC-16 is 8.0 and 35℃,respectively.Meanwhile,degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient(R 2 >0.99) .Furthermore,the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate.This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments.展开更多
文摘Acinetobacter sp.WML1分离自淡水湖渔场沉积物,能降解几丁质,具有一定的应用价值。为了评价菌株WML1的生物安全性,为菌株的安全使用提供参考和保障,采用常规纸片扩散法检测耐药性,用血琼脂平板划线法检测溶血性,用溴甲酚紫显色法检测氨基酸脱羧酶活性,用试剂盒测定硝酸还原酶活性。在菌株生物安全性分析的基础上,通过单因素试验法和正交试验法进行菌株WML1产几丁质酶发酵条件的优化。结果表明,菌株WML1对多种抗生素敏感,无溶血性,无硝酸还原酶活性,有精氨酸脱羧酶活性及微弱的赖氨酸和鸟氨酸脱羧酶活性;其最优产酶条件为0.4%黄豆粉、0.20%半乳糖、0.03%KH2PO4、0.07%K2HPO4、0.002%FeSO_(4)、0.05%Mg SO_(4)·7H2O、0.001%ZnSO_(4)、0.60%胶体几丁质、pH 9.5、5.0%的接种量、25 m L的装液量(对应250 m L容量瓶)、37℃的培养温度,优化后的几丁质酶活为(2.72±0.09)U/m L。综上所述,不动杆菌WML1在使用安全性上危害较小,可防可控,经发酵条件优化后其所产几丁质酶的活性提高了约4.61倍,为产几丁质酶菌株的工业化应用提供了理论基础。
基金Project supported by the Undergraduate Research Foundation of Nankai University (2004).
文摘A new phenol-degrading bacterium with high biodegradation activity and high tolerance of phenol, strain PD 12, was isolated from the activated sludge of Tianjin Jizhuangzi Wastewater Treatment Facility in China. This strain was capable of removing 500 mg phenol/L in liquid minimal medium by 99.6% within 9 h and metabolizing phenol at concentrations up to 1100 mg/L. DNA sequencing and homologous analysis of 16S rRNA gene identified PD12 to be an Acinetobacter sp. Polyvinyl alcohol （PVA） was used as a gel matrix to immobilize Acinetobacter sp. strain PDI2 by repeated freezing and thawing. The factors affecting phenol degradation of immobilized cells were investigated, and the results showed that the immobilized cells could tolerate a high phenol level and protected the bacteria against changes in temperature and pH. Storage stability and reusability tests revealed that the phenol degradation functions of immobilized cells were stable after reuse for 50 times or storing at 4℃ for 50 d. These results indicate that immobilized Acinetobacter sp. strain PD 12 possesses a good application potential in the treatment of phenol-containing wastewater.
文摘提出一种新的方法,用于富集苯并[a]芘耐受菌株。该方法使用多孔介质脱脂棉作为载体,从连续流动的流体——下水道污水中富集菌株。利用介质截留法、富集培养法等理论,为富集目标微生物提供了最佳条件。以苯并[a]芘为唯一碳源和能源,从下水道沉积物中分离、筛选出4株苯并[a]芘耐受菌株,其中一株能在20天内将40 mg/L的苯并[a]芘降解28.7%。通过16S r RNA基因序列分析和部分生理生化特征分析,鉴定该菌株为Acinetobacter sp.Bap30。这是不动杆菌可降解苯并[a]芘的首次报道。添加其他碳源和低分子量多环芳烃——菲作为共代谢底物,研究菌株的共代谢作用。研究结果对石油污染的土壤或者焦化废水等工业污水中的高分子量多环芳烃——苯并[a]芘具有非常重要的实践意义。
基金supported by grants from National Natural Science Foundation of China(51078106)Heilongjiang Provincial Science Foundation for Distinguished Youth Scholar(JC200708)Heilongjiang Provincial Finance Foundation for Basic Sciences(CZ12BZSM06)
文摘Objective To purify a low-temperature hydroxylamine oxidase （HAO） from a heterotrophic nitrifying bacterium Acinetobacter sp. Y26 and investigate the enzyme property. Methods A HAO was purified by an anion-exchange and gel-filtration chromatography from strain Y16. The purity and molecular mass were determined by RP-HPLC and SDS-PAGE. The HAO activity was detected by monitoring the reduction of potassium ferricyanide using hydroxylamine as substrate and ferricyanide as electron acceptor. The partial amino acid sequence was determined by mass spectrometry. Results The low-temperature HAO with a molecular mass of 61 kDa was purified from strain Y26 by an anion-exchange and gel-filtration chromatography. The enzyme exhibited an ability to oxidize hydroxylamine in wide temperature range （4-40 ℃） in vitro using hydroxylamine as substrate and ferricyanide as electron acceptor. It was stable in the temperature range of 4 to 25 ℃ and pH range of 6.0 to 8.5 with less than 30% change in its activity. The optimal temperature and pH were 15 ℃ and 7.5, respectively. Three peptides were determined by mass spectrometry which were shown to be not identical to other reported HAOs. Conclusion This is the first study to purify a low-temperature HAO from a heterotrophic nitrifier Acinetobecter sp. It differs from other reported HAOs in molecular mass and enzyme properties. The findings of the present study have suggested that the strain Y26 passes through a hydroxylamine-oxidizing process catalyzed by a low-temperature HAO for ammonium removal.
基金Project(30770388) supported by the National Natural Science Foundation of China
文摘A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological and biochemical properties and analysis of 16S rRNA gene sequence,it was preliminarily identified belonging to the genus Acinetobacter.The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate(DINP) .The degradation tests using diethyl phthalate(DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp.JDC-16 is 8.0 and 35℃,respectively.Meanwhile,degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient(R 2 >0.99) .Furthermore,the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate.This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments.
