A bioflocculant-producing mutator strain, NIM-192, was screened out through nitrogen ion implanting into F J-7 strain. The results showed that NIM-192 had good genetic stability and high flocculating activity, and the...A bioflocculant-producing mutator strain, NIM-192, was screened out through nitrogen ion implanting into F J-7 strain. The results showed that NIM-192 had good genetic stability and high flocculating activity, and the flocculating rate increased by 34.26% than that of the original. Sucrose, complex nitrogen source contained yeast extract, urea and pH 7.0～ 9.0 were chosen as the best carbon source, nitrogen source and initial solution pH for bioflocculant production, respectively. The bioflocculant kept high and stable flocculating activity at alkalinous reaction mixture with a pH beyond 7.0, while the flocculating activity was remarkably reduced when the reaction pH was lower than 7.0. Addition of many cations could obviously increase the flocculating rate, among which Ca^2＋ demonstrated the best effect. The bioflocculant had very strong acid-base stability and thermo-stability.The flocculating rate kept over 86% when pH of the bioflocculant was in a range of 3.0 ～ 12.0, and the change of flocculating activity was not great when heated at 100℃ for 60 rain.展开更多
In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological cha...In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological changes in the bacteria were observed by scanning electron microscope （SEM）. The optimum condition of ions implantation, 20 keV of energy and 2.6 × 10^15N^＋/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wild strain. The microbial growth and biosurfactant production of both the mutant and the wild strain were compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was determined to be a complex of surfactin family through analysis of electrospray ionization mass spectrum （ESI/MS） and there was an interesting finding that after the ion beam implantation the intensities of the components were different from the wild type strain.展开更多
基金the State Key Development Program for Basic Research of China(No.2004CB719604)
文摘A bioflocculant-producing mutator strain, NIM-192, was screened out through nitrogen ion implanting into F J-7 strain. The results showed that NIM-192 had good genetic stability and high flocculating activity, and the flocculating rate increased by 34.26% than that of the original. Sucrose, complex nitrogen source contained yeast extract, urea and pH 7.0～ 9.0 were chosen as the best carbon source, nitrogen source and initial solution pH for bioflocculant production, respectively. The bioflocculant kept high and stable flocculating activity at alkalinous reaction mixture with a pH beyond 7.0, while the flocculating activity was remarkably reduced when the reaction pH was lower than 7.0. Addition of many cations could obviously increase the flocculating rate, among which Ca^2＋ demonstrated the best effect. The bioflocculant had very strong acid-base stability and thermo-stability.The flocculating rate kept over 86% when pH of the bioflocculant was in a range of 3.0 ～ 12.0, and the change of flocculating activity was not great when heated at 100℃ for 60 rain.
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No.KSCX2-SW-324)
文摘In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological changes in the bacteria were observed by scanning electron microscope （SEM）. The optimum condition of ions implantation, 20 keV of energy and 2.6 × 10^15N^＋/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wild strain. The microbial growth and biosurfactant production of both the mutant and the wild strain were compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was determined to be a complex of surfactin family through analysis of electrospray ionization mass spectrum （ESI/MS） and there was an interesting finding that after the ion beam implantation the intensities of the components were different from the wild type strain.
