The properties of Pt 4+ adsorption and its reduction by Bacillus megaterium D01 were studied by means of ICP, anode stripping voltammetry, TEM, IR and XPS. The results of ICP analyses showed that the Pt 4+ adsorptive ...The properties of Pt 4+ adsorption and its reduction by Bacillus megaterium D01 were studied by means of ICP, anode stripping voltammetry, TEM, IR and XPS. The results of ICP analyses showed that the Pt 4+ adsorptive efficiency of the strain D01 was as high as 94.3% under the conditions of 100 mg Pt 4+ /L, 1 g biomass/L, pH 3.5 and at 30 ℃ for 24 h. Moreover, it was confirmed from anode stripping voltammetry that the strain D01 possessed a strong reducibility. The TEM analysis indicated that the strain D01 was able to adsorb and reduce Pt 4+ to Pt 0, small particles. The XPS result further supported the reduction of Pt 4+ to Pt 2+ , followed by the further recuction to Pt 0. The IR spectrum implied that D01 biomass adsorption of Pt 4+ may result in the complexation of the CO bond to the Pt species.展开更多
Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbosedehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase(SDH) of Gluconobacter oxydans in the 2-keto-L-gu...Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbosedehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase(SDH) of Gluconobacter oxydans in the 2-keto-L-gulonic acid (2KLG) fermentation from L-sorboseby the mixed culture of B.megaterium BM302 and G.oxydans.The SAP purified by threechromatographic steps gave 35-fold purification with a yield of 13% and a specific activity of5.21 units/mg protein.The molecular weight of the purified SAP was about 58 kDa.The SDHaccelerative activity of SAP at pH 7 and 50℃ was the highest.Additionally,it retained 60%activity at a pH range of 6.5～10 and was stable at 20℃～60℃.After 0.32-unit SAP was addedto the single cultured G.oxydans strains,the SDH activity was apparently accelerated and the2KLG yield of GO29,GO112,G0 and G113 was enhanced 2.1,3.3,3.5 and 2.9 folds respectivelyover that of the strains without the addition of SAP.展开更多
Bacillus megaterium as a companion strain in two-stage fermentation of vitamin Ccould secrete some active substances to spur growth of Gluconobacter oxydans to produce 2-KLG.In the fermenting system where Gluconobacte...Bacillus megaterium as a companion strain in two-stage fermentation of vitamin Ccould secrete some active substances to spur growth of Gluconobacter oxydans to produce 2-KLG.In the fermenting system where Gluconobacter oxydans was combined with GB82-a mutatedstrain of B. megaterium by ion implantation, the amount of 2-KLG harvested was larger thanthat produced by the original B. megaterium BP52[1] being substituted for GB82. In this paper,we studied the effect of the active substances secreted by GB82 to enhance the capability ofGluconobacter oxydans to produce 2-KLG. The supernate of GB82 sampled at different cultivationtimes all had much more activity to spur Gluconobacter oxydans to yield 2-KLG than that of theoriginal B. megaterium, which might be due to the genetic changes in the active componentscaused by ion implantation. Furthermore, the active substances of GB82's supernate would losea part of its activity in extreme environments, which is typical of some proteins.展开更多
基金Supported by the National Natural Science Foundation of China(No.2 97430 0 1 and No.2 9876 0 2 6 )
文摘The properties of Pt 4+ adsorption and its reduction by Bacillus megaterium D01 were studied by means of ICP, anode stripping voltammetry, TEM, IR and XPS. The results of ICP analyses showed that the Pt 4+ adsorptive efficiency of the strain D01 was as high as 94.3% under the conditions of 100 mg Pt 4+ /L, 1 g biomass/L, pH 3.5 and at 30 ℃ for 24 h. Moreover, it was confirmed from anode stripping voltammetry that the strain D01 possessed a strong reducibility. The TEM analysis indicated that the strain D01 was able to adsorb and reduce Pt 4+ to Pt 0, small particles. The XPS result further supported the reduction of Pt 4+ to Pt 2+ , followed by the further recuction to Pt 0. The IR spectrum implied that D01 biomass adsorption of Pt 4+ may result in the complexation of the CO bond to the Pt species.
基金the General Program of National Science Foundation of China(No.10375066)
文摘Bacillus megaterium BM302 bred by ion-beam implantation produces L-sorbosedehydrogenase accelerative protein (SAP) to accelerate the activity of L-sorbose dehydrogenase(SDH) of Gluconobacter oxydans in the 2-keto-L-gulonic acid (2KLG) fermentation from L-sorboseby the mixed culture of B.megaterium BM302 and G.oxydans.The SAP purified by threechromatographic steps gave 35-fold purification with a yield of 13% and a specific activity of5.21 units/mg protein.The molecular weight of the purified SAP was about 58 kDa.The SDHaccelerative activity of SAP at pH 7 and 50℃ was the highest.Additionally,it retained 60%activity at a pH range of 6.5～10 and was stable at 20℃～60℃.After 0.32-unit SAP was addedto the single cultured G.oxydans strains,the SDH activity was apparently accelerated and the2KLG yield of GO29,GO112,G0 and G113 was enhanced 2.1,3.3,3.5 and 2.9 folds respectivelyover that of the strains without the addition of SAP.
文摘Bacillus megaterium as a companion strain in two-stage fermentation of vitamin Ccould secrete some active substances to spur growth of Gluconobacter oxydans to produce 2-KLG.In the fermenting system where Gluconobacter oxydans was combined with GB82-a mutatedstrain of B. megaterium by ion implantation, the amount of 2-KLG harvested was larger thanthat produced by the original B. megaterium BP52[1] being substituted for GB82. In this paper,we studied the effect of the active substances secreted by GB82 to enhance the capability ofGluconobacter oxydans to produce 2-KLG. The supernate of GB82 sampled at different cultivationtimes all had much more activity to spur Gluconobacter oxydans to yield 2-KLG than that of theoriginal B. megaterium, which might be due to the genetic changes in the active componentscaused by ion implantation. Furthermore, the active substances of GB82's supernate would losea part of its activity in extreme environments, which is typical of some proteins.
