关键词: 固氮, 甘蔗根部, 菌种鉴定, 生化试验, 成团泛菌

Abstract: A strain of nitrogen-fixing bacteria, W11, isolated from the root of sugar cane has been identificated as Pantoea agglomeras using an auto-identificat ion system for bacterium based on 96 biochemical test data. W11 has the properties of tolerance to acid(pH3.5) and high sucrose concentration (30%), A amount of acid was formed and reduced the acidity of medium to pH of 4.41, the nitrogenase activity was inhibited in presence of 3.1mmol NH₄NO₃ or 58.5mmol NaNO₃. The optimum growth and maximum nitrogenase activity of W11 occurs at the medium containing 10% sucrose and 0.25g/L sodium glutamate, pH5.5, 28-30^oC. Its behaviours of tolerance to acid and high sucrose concentration, acid production and the use of carbon substrates is simiiar to that the Acetobacter diazotrophicus has. The strain W11 was inferred to have a nitrogen-fixing relationship associated with the root of sugar cane.

Key words: nitrogen fixation, root of sugar cane, identification of strain, biochemical test, Pantoea agglomera