A new method was used to preparing genomic DNA from Microbacterium sp.quickly and efficiently.DNA quantity and purity was measured by UV absorbance.Integrity of the genomic DNA was tested by agarose gel eletrophoresis...A new method was used to preparing genomic DNA from Microbacterium sp.quickly and efficiently.DNA quantity and purity was measured by UV absorbance.Integrity of the genomic DNA was tested by agarose gel eletrophoresis.The DNA prepared by this method was sufficiently pure for PCR.This method saves time and cost,practices easily as well.展开更多
The carbendazim（MBC） hydrolyzing enzyme gene was cloned and heterologously expressed in Escherichia coli BL21（DE3） from a newly isolated MBC-degrading bacterium strain Microbacterium sp. strain djl-6F. High perfor...The carbendazim（MBC） hydrolyzing enzyme gene was cloned and heterologously expressed in Escherichia coli BL21（DE3） from a newly isolated MBC-degrading bacterium strain Microbacterium sp. strain djl-6F. High performance liquid chromatography-mass spectrometry（HPLC-MS）analysis revealed that purified MheI-6F protein catalyzes direct hydrolysis of MBC into2-aminobenzimidazole（2-AB） with a high turnover rate and moderate affinity（Kmof6.69 μmol/L and kcatof 160.88/min） without the need for any cofactors. The optimal catalytic condition of MheI-6F was identified as 45°C, pH 7.0. The enzymatic activity of MheI-6F was found to be diminished by metal ions, and strongly inhibited by sodium dodecyl sulfate（SDS）.Through generating amino acid mutations in MheI-6F, Cys16 and Cys222 were identified as the catalytic groups that are essential for the hydrolysis of MBC. This is the first report on the biodegradation of MBC at the enzymatice level.展开更多
We searched for a superior melamine-degrading bacterium for the bioremediation of melamine. Cyanuric acid, which is a by-product produced during the biodegradation of melamine, shows strong nephrotoxicity. Therefore, ...We searched for a superior melamine-degrading bacterium for the bioremediation of melamine. Cyanuric acid, which is a by-product produced during the biodegradation of melamine, shows strong nephrotoxicity. Therefore, the melamine-degrading bacterium is also required to show a high ability to degrade cyanuric acid. We selected a melamine-degrading strain (MEL1) among ten cyanuric acid-degrading bacteria isolated from the soil. The species of MEL1 strain was Microbacterium esteramaticum or was extremely similar to that species, and the enzymatic activity of the melamine deaminase in the MEL1 strain was similar to that in the NRRLB-12227 strain. The ability of the MEL1 strain to degrade cyanuric acid was higher than its ability to degrade melamine, and therefore, the accumulation of by-products (ammeline, ammelide and cyanuric acid) during the degradation of melamine was minimal. These results suggest that the MEL1 strain is useful for the bioremediation of melamine.展开更多
Bacterial isolation from oil-contaminated and uncontaminated soil was screened for hydrocarbon utilizer which was also capable of producing lysine. Microbial production of lysine by Microbacterium lacticum was investi...Bacterial isolation from oil-contaminated and uncontaminated soil was screened for hydrocarbon utilizer which was also capable of producing lysine. Microbial production of lysine by Microbacterium lacticum was investigated in submerged fermentations using various concentrations of hydrocarbon, sugar sources and nitrogen. Of the nine sugar and five nitrogen sources tested, glucose/ammonium sulphate proved optimum for lysine production. Effect of varying concentration of carbon and nitrogen sources on lysine accumulation showed that glucose (4%) ammonium sulphate (1%) respectively increased lysine production. A gram positive rod bacterium identified as Microbacterium lacticum was identified. Optimizing the cultural conditions of Microbacterium lacticum in submerged medium gave a methionine yield of 2.99 mg/ml lysine in the broth culture after 96 h.展开更多
文摘A new method was used to preparing genomic DNA from Microbacterium sp.quickly and efficiently.DNA quantity and purity was measured by UV absorbance.Integrity of the genomic DNA was tested by agarose gel eletrophoresis.The DNA prepared by this method was sufficiently pure for PCR.This method saves time and cost,practices easily as well.
基金supported by the Hi-Tech Research and Development Program(863) of China(No.2012AA101404)the National Natural Science Foundation of China(No.31301700)+1 种基金the Science and Technology Program of BaoJi(No.2013R6-3)the Key Subject Project of Baoji University of Arts and Sciences(No.ZK0919)
文摘The carbendazim（MBC） hydrolyzing enzyme gene was cloned and heterologously expressed in Escherichia coli BL21（DE3） from a newly isolated MBC-degrading bacterium strain Microbacterium sp. strain djl-6F. High performance liquid chromatography-mass spectrometry（HPLC-MS）analysis revealed that purified MheI-6F protein catalyzes direct hydrolysis of MBC into2-aminobenzimidazole（2-AB） with a high turnover rate and moderate affinity（Kmof6.69 μmol/L and kcatof 160.88/min） without the need for any cofactors. The optimal catalytic condition of MheI-6F was identified as 45°C, pH 7.0. The enzymatic activity of MheI-6F was found to be diminished by metal ions, and strongly inhibited by sodium dodecyl sulfate（SDS）.Through generating amino acid mutations in MheI-6F, Cys16 and Cys222 were identified as the catalytic groups that are essential for the hydrolysis of MBC. This is the first report on the biodegradation of MBC at the enzymatice level.
文摘We searched for a superior melamine-degrading bacterium for the bioremediation of melamine. Cyanuric acid, which is a by-product produced during the biodegradation of melamine, shows strong nephrotoxicity. Therefore, the melamine-degrading bacterium is also required to show a high ability to degrade cyanuric acid. We selected a melamine-degrading strain (MEL1) among ten cyanuric acid-degrading bacteria isolated from the soil. The species of MEL1 strain was Microbacterium esteramaticum or was extremely similar to that species, and the enzymatic activity of the melamine deaminase in the MEL1 strain was similar to that in the NRRLB-12227 strain. The ability of the MEL1 strain to degrade cyanuric acid was higher than its ability to degrade melamine, and therefore, the accumulation of by-products (ammeline, ammelide and cyanuric acid) during the degradation of melamine was minimal. These results suggest that the MEL1 strain is useful for the bioremediation of melamine.
文摘Bacterial isolation from oil-contaminated and uncontaminated soil was screened for hydrocarbon utilizer which was also capable of producing lysine. Microbial production of lysine by Microbacterium lacticum was investigated in submerged fermentations using various concentrations of hydrocarbon, sugar sources and nitrogen. Of the nine sugar and five nitrogen sources tested, glucose/ammonium sulphate proved optimum for lysine production. Effect of varying concentration of carbon and nitrogen sources on lysine accumulation showed that glucose (4%) ammonium sulphate (1%) respectively increased lysine production. A gram positive rod bacterium identified as Microbacterium lacticum was identified. Optimizing the cultural conditions of Microbacterium lacticum in submerged medium gave a methionine yield of 2.99 mg/ml lysine in the broth culture after 96 h.
