BIOLOGICAL NITROGEN-FIXATION AT ELEVATED-TEMPERATURE IN DIFFERENT AZOSPIRILLUM SPECIES AND STRAINS

Nitrogenase activity, nitrogenase synthesis, and the growth of four species of Azospirillum were examined at 30 degrees C and 42 degrees C. Azospirillum brasilense Sp7 did not synthesize nitrogenase at 42 degrees C nor was the enzyme stable at this temperature. In A. lipoferum 708 and A. brasilense 12S the nitrogenase activity was stable at 42 degrees C but the synthesis of nitrogenase was reduced. In A. brasilense Sp9 the nitrogenase activity was stable and showed the highest C2H2 reduction activity at 42 degrees C.