Production of pantothenic acid and thiamine by Azotobacter vinelandii in a chemically defined medium and a dialysed soil medium

The production of pantothenic acid and thiamine by Azotobacter vinelandii was studied in a chemically defined medium and a dialysed soil medium amended with different amounts of carbohydrate and NH4+. Pantothenic acid and thiamine were produced in large amounts in the culture medium containing 2.0-5.0% glucose and 0.1-0.3% NH4Cl. The results showed that the liberation of these vitamins was increased under adiazotrophic conditions and with an excess of C source. Group of Environmental Microbiology, Department of Microbiology, Faculty of Pharmacy and Institute of Water Research, University of Granada, 18071 Granada, Spain. significantly to the N demand of plants (Martinez-Toledo et al. 1991), It has been suggested that Azotobacter spp. might increase plant growth by synthesizing plant-growth substances such as auxins, gibberellins, and cytokinins (Gonzalez-Lopez et al. 1991). The vitamins pantothenic acid and thiamine are produced in large amounts by Azotobacter spp. (Gonzalez-Lopez et al, 1983). We therefore studied the liberation of these vitamins by A. vinelandii in chemically defined and dialysed soil media with different concentrations of C and N, in order to evaluate the influence of the nutrient content on the liberation of vitamins by this organism.