A compound bioflocculant CBF,produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its production and flocculating properties. The optimization of the culture...A compound bioflocculant CBF,produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its production and flocculating properties. The optimization of the culture medium constituents including carbon source,nitrogen source and C / N ratio,metal ions and ionic strength on CBF production were studied. Flocculating properties of CBF were examined by a series of experiments and CBF had good flocculating activities in kaolin suspension with divalent cations and stable over wide range of p H. Studies of the flocculating properties revealed that the flocculation could be stimulated by cations Ca2+,Mg2+,Fe2+,Al3+and Fe3+. In addition,it was stable at 4-30 ℃ in the presence of Ca Cl2. It was found to be effective for flocculation of a kaolin suspension under neutral and weak alkaline conditions( p H 7. 0- 9. 0),and flocculating activities of higher than 95% were obtained when the CBF concentrations among 6- 14 mg / L at p H 8. 0. The results of this study indicate that CBF is a potential replacement of conventional synthetic flocculants and is widely applied in water treatment and downstream processing of food and fermentation industries.展开更多
[Objectives] This study was conducted to analyze the infection ability of Rhizobium radiobacter from Rosa chinensis to peach tree,so as to provide a theoretical basis for the identification and control of crown gall o...[Objectives] This study was conducted to analyze the infection ability of Rhizobium radiobacter from Rosa chinensis to peach tree,so as to provide a theoretical basis for the identification and control of crown gall of peach. [Methods]With peach variety ＂ Chiyohime＂ as an experimental material,R. radiobacter GOU1 was extracted from crown gall tissue of R. chinensis susceptible to crown gall,and its infection ability to peach tree was studied by in-vitro dip method.[Results]Stem segments of peach tree were inoculated with R. radiobacter GOU1 by in-vitro dip method. Calli grew rapidly after inoculation,and 28 d later,the infection rate of R. radiobacter GOU1 was 50%,indicating that R. radiobacter GOU1 could infect peach tree easier. The infection on stem segments of peach tree could be detected in the fourth week by in-vitro dip method. Culturing peach stem segments in MS medium containing 10 μM/L NAA and 10 μM/L BAP in vitro is beneficial to survival and could promote growth of callus. [Conclusions]The detection rate of R. radiobacter GOU1 infection on stem segments of peach tree did not change from the fourth week to the sixth week. Therefore,in future studies,the detection of R. radiobacter infection on inoculated stem segments of peach tree could be performed after 4 weeks of culture rather than 6 weeks of culture.展开更多
Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal...Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4C1 has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition （10 rag/L）. When the effect of increasing inoculum concentration on decolorization of Crystal Violet （100 mg/L） was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase （184%） and aminopyrine N-demethylase （300%） in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy （GC/MS）. It was detected the presence of N,N,N＇,N＂-tetramethylpararosarfiline, IN, N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N, N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria （A. radiobacter, P. aurugenosa and A. vinelandii） contributing to soil fertility and for four kinds of plants （Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum） which are most sensitive, fast growing and commonly used in Indian agriculture.展开更多
基金Sponsored by the National High Technology Research and Development Program of China(Grant No.2009AA062906)the"Twelfth Five-Year Plan"National Key Technology R&D Program of China(Grant No.2012BAD14B06-04)+2 种基金the National Natural Science Foundation of China(Grant No.51478140&51408200)State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(Grant No.2015DX06)Promising Youngsters Training Program of Heilongjiang University of Science and Technology(Grant No.Q20120201)
文摘A compound bioflocculant CBF,produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its production and flocculating properties. The optimization of the culture medium constituents including carbon source,nitrogen source and C / N ratio,metal ions and ionic strength on CBF production were studied. Flocculating properties of CBF were examined by a series of experiments and CBF had good flocculating activities in kaolin suspension with divalent cations and stable over wide range of p H. Studies of the flocculating properties revealed that the flocculation could be stimulated by cations Ca2+,Mg2+,Fe2+,Al3+and Fe3+. In addition,it was stable at 4-30 ℃ in the presence of Ca Cl2. It was found to be effective for flocculation of a kaolin suspension under neutral and weak alkaline conditions( p H 7. 0- 9. 0),and flocculating activities of higher than 95% were obtained when the CBF concentrations among 6- 14 mg / L at p H 8. 0. The results of this study indicate that CBF is a potential replacement of conventional synthetic flocculants and is widely applied in water treatment and downstream processing of food and fermentation industries.
基金Supported by Natural Science Foundation of China(31260461)Guangxi Innovation Team Nanning Test Station Project of National Modern Agriculture Technology System(nycytxcxtd-03-12-3,nycytxcxtd-04-18)Undergraduate Teaching Reform Project of Higher Education of Guangxi Province(2017JGB132)
文摘[Objectives] This study was conducted to analyze the infection ability of Rhizobium radiobacter from Rosa chinensis to peach tree,so as to provide a theoretical basis for the identification and control of crown gall of peach. [Methods]With peach variety ＂ Chiyohime＂ as an experimental material,R. radiobacter GOU1 was extracted from crown gall tissue of R. chinensis susceptible to crown gall,and its infection ability to peach tree was studied by in-vitro dip method.[Results]Stem segments of peach tree were inoculated with R. radiobacter GOU1 by in-vitro dip method. Calli grew rapidly after inoculation,and 28 d later,the infection rate of R. radiobacter GOU1 was 50%,indicating that R. radiobacter GOU1 could infect peach tree easier. The infection on stem segments of peach tree could be detected in the fourth week by in-vitro dip method. Culturing peach stem segments in MS medium containing 10 μM/L NAA and 10 μM/L BAP in vitro is beneficial to survival and could promote growth of callus. [Conclusions]The detection rate of R. radiobacter GOU1 infection on stem segments of peach tree did not change from the fourth week to the sixth week. Therefore,in future studies,the detection of R. radiobacter infection on inoculated stem segments of peach tree could be performed after 4 weeks of culture rather than 6 weeks of culture.
文摘Agrobacterium radiobacter MTCC 8161 completely decolorized the Crystal Violet with 8 hr （10 mg/L） at static anoxic conditions. The decreased decolorization capability by A. radiobacter was observed, when the Crystal Violet concentration was increased from 10 to 100 mg/L. Semi-synthetic medium containing 1% yeast extract and 0.1% NH4C1 has shown 100% decolorization of Crystal Violet within 5 hr. A complete degradation of Crystal Violet by A. radiobacter was observed up to 7 cycles of repeated addition （10 rag/L）. When the effect of increasing inoculum concentration on decolorization of Crystal Violet （100 mg/L） was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase （184%） and aminopyrine N-demethylase （300%） in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process. The intermediates formed during the degradation of Crystal Violet were analyzed by gas chromatography and mass spectroscopy （GC/MS）. It was detected the presence of N,N,N＇,N＂-tetramethylpararosarfiline, IN, N-dimethylaminophenyl] [N-methylaminophenyl] benzophenone, N, N-dimethylaminobenzaldehyde, 4-methyl amino phenol and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria （A. radiobacter, P. aurugenosa and A. vinelandii） contributing to soil fertility and for four kinds of plants （Sorghum bicolor, Vigna radiata, Lens culinaris and Triticum aestivum） which are most sensitive, fast growing and commonly used in Indian agriculture.
