为增强固氮酶活性以提高现有固氮菌的固氮能力,采用常压室温等离子体(atmospheric and room temperature plasma,ARTP)诱变技术处理褐球固氮菌(Azotobacter chroococcum)CICC21686,用乙炔还原法筛选具有高固氮酶活性的突变株28s-20,并...为增强固氮酶活性以提高现有固氮菌的固氮能力,采用常压室温等离子体(atmospheric and room temperature plasma,ARTP)诱变技术处理褐球固氮菌(Azotobacter chroococcum)CICC21686,用乙炔还原法筛选具有高固氮酶活性的突变株28s-20,并观察该突变株酶活的遗传稳定性;通过梯度温度和pH培养,探究高酶活突变株的生物学活性;采用盆栽试验,探究突变株对玉米植株干重及全氮量的影响。结果表明,复筛获得突变株28s-20的固氮酶活较出发菌株提高了101.72%;经5次传代,证实该菌株具有良好的遗传稳定性;突变株最适生长温度为28℃,培养基初始pH为7.5;与野生株相比,突变株显著增加玉米干重及全氮量,分别提高21.16%和34.36%。诱变高酶活菌株为褐球固氮菌的菌种优化及农业生物固氮提供了技术支持。展开更多
Biosorption of silver ions onto A. chroococcum XU1 biomass and exopolysaccharide (EPS) was investigated. It was found that the overall biosorption process was the best when cell biomass and EPS were used together. Met...Biosorption of silver ions onto A. chroococcum XU1 biomass and exopolysaccharide (EPS) was investigated. It was found that the overall biosorption process was the best when cell biomass and EPS were used together. Metal adsorption experiments showed that the final precipitate obtained by cell biomass and EPS, contained 7.85% of Ag. Based on the results presented in this study, the biomass and EPS of A. chroococcum XU1 indicated the possibility of application of them as biosorbent for removal of silver from waste waters.展开更多
The persistence and performance (growth promoting potential) of green fluorescent protein (gfp) marked Azotobacter chroococcum strain ABR 4G were studied in sterilized and unsterilized wheat rhizospheric soil. The gfp...The persistence and performance (growth promoting potential) of green fluorescent protein (gfp) marked Azotobacter chroococcum strain ABR 4G were studied in sterilized and unsterilized wheat rhizospheric soil. The gfp was integrated via Tn 5 transposition into A. chroococcum chromosome and the resultant gfp marked colonies were identified by green fluorescent emission under UV light. The gfp was stably maintained in A. chroococcum and the gfp insertion had no apparent adverse effect on the growth promoting properties of the marked soil isolate ABR 4G. The growth promoting properties (nitrogen fixation, ammonia excretion, phosphate solubilization and IAA production) of the parent soil isolate and the gfp marked strain were found to be almost the same. All the quantitative wheat plant traits were significantly influenced by inoculation of A. chroococcum ABR 4G strain in sterilized and unsterilized soil. Inoculated bacterial counts increased gradually in wheat rhizosphere, reached maximum on 60 th d and declined on 80 th d. Fertility levels also affected survival of marked strain and the survival was comparable in sterilized and unsterilized soil. The growth promoting properties were also determined from the marked strain reisolated from wheat rhizosphere in both types of soil. Fig 1, Tab 2, Ref展开更多
文摘为增强固氮酶活性以提高现有固氮菌的固氮能力,采用常压室温等离子体(atmospheric and room temperature plasma,ARTP)诱变技术处理褐球固氮菌(Azotobacter chroococcum)CICC21686,用乙炔还原法筛选具有高固氮酶活性的突变株28s-20,并观察该突变株酶活的遗传稳定性;通过梯度温度和pH培养,探究高酶活突变株的生物学活性;采用盆栽试验,探究突变株对玉米植株干重及全氮量的影响。结果表明,复筛获得突变株28s-20的固氮酶活较出发菌株提高了101.72%;经5次传代,证实该菌株具有良好的遗传稳定性;突变株最适生长温度为28℃,培养基初始pH为7.5;与野生株相比,突变株显著增加玉米干重及全氮量,分别提高21.16%和34.36%。诱变高酶活菌株为褐球固氮菌的菌种优化及农业生物固氮提供了技术支持。
文摘Biosorption of silver ions onto A. chroococcum XU1 biomass and exopolysaccharide (EPS) was investigated. It was found that the overall biosorption process was the best when cell biomass and EPS were used together. Metal adsorption experiments showed that the final precipitate obtained by cell biomass and EPS, contained 7.85% of Ag. Based on the results presented in this study, the biomass and EPS of A. chroococcum XU1 indicated the possibility of application of them as biosorbent for removal of silver from waste waters.
文摘以餐厨垃圾湿热处理脱出液为发酵培养基,选用圆褐固氮菌(Azotobacter chroococcum)作为实验菌种制作固氮液态菌肥。测定了圆褐固氮菌的主要生理特性,将其接种于餐厨湿热处理脱出液中进行培养,确定最佳发酵时间,并分别测定发酵的最佳初始p H值、接种量、培养温度、摇床转速、装液量、脱出液与水的混合比例。结果表明:圆褐固氮菌在餐厨湿热处理脱出液中最佳发酵时间为36 h,发酵最佳初始p H值、接种量、培养温度、摇床转速、装液量、脱出液与水的混合比例依次为7.5、1%、30℃、150 r/min、50 m L(250 m L锥形瓶)、1∶1。圆褐固氮菌在餐厨垃圾湿热处理脱出液中进行培养后,可达到液态菌肥的活菌数标准。
文摘The persistence and performance (growth promoting potential) of green fluorescent protein (gfp) marked Azotobacter chroococcum strain ABR 4G were studied in sterilized and unsterilized wheat rhizospheric soil. The gfp was integrated via Tn 5 transposition into A. chroococcum chromosome and the resultant gfp marked colonies were identified by green fluorescent emission under UV light. The gfp was stably maintained in A. chroococcum and the gfp insertion had no apparent adverse effect on the growth promoting properties of the marked soil isolate ABR 4G. The growth promoting properties (nitrogen fixation, ammonia excretion, phosphate solubilization and IAA production) of the parent soil isolate and the gfp marked strain were found to be almost the same. All the quantitative wheat plant traits were significantly influenced by inoculation of A. chroococcum ABR 4G strain in sterilized and unsterilized soil. Inoculated bacterial counts increased gradually in wheat rhizosphere, reached maximum on 60 th d and declined on 80 th d. Fertility levels also affected survival of marked strain and the survival was comparable in sterilized and unsterilized soil. The growth promoting properties were also determined from the marked strain reisolated from wheat rhizosphere in both types of soil. Fig 1, Tab 2, Ref
