| Abstract: | On addition of low concentrations (0.005%) of Triton X-100 to a mineral medium supplemented with 0.5% heptadecane, a marked stimulation of growth rate was observed for Acinetobacter calcoaceticus strains able to grow on alkanes while appreciable amounts of soluble quinoprotein d-glucose dehydrogenase d-glucose: (pyrroloquinoline-quinone) 1-oxidoreductase, EC 1.1.99.17] were found in the culture medium. At higher Triton X-100 concentrations (0.04%), still larger amounts of d-glucose dehydrogenase and also cytoplasmic enzyme activities appeared in the culture medium. Although combinations of other carbon sources plus non-ionic detergents also produced these enzymes in the medium, the combination of heptadecane and Triton X-100 gave higher levels and had a stabilizing effect on d-glucose dehydrogenase. Therefore, by using this combination and culturing within certain pH limits, a stable enzyme solution, having already a high specific activity, is produced while the cell harvesting and disruption steps can be circumvented. The results indicate that d-glucose dehydrogenase in this organism is a periplasmic enzyme, coupled to a cytochrome b. |
