Gluconic acid produced by Gluconacetobacter diazotrophicus PAL5 possesses antimicrobial properties

NIETO-PEÑALVER, C. G.; SAVINO, J. M.; BERTINI, E. V.; SANCHEZ L. A; CASTELLANOS DE FIGUEROA, L. I

RESEARCH IN MICROBIOLOGY

ELSEVIER SCIENCE BV

Año: 2014 vol. 165 p. 549 - 558

0923-2508

Gluconic acid is produced in large quantities by the endophytic and diazotrophic bacterium Gluconacetobacter diazotrophicus PAL5. This organic acid derives from the direct oxidation of glucose by means of a pyrroloquinoline quinone-linked glucose dehydrogenase in this plant growth-promoting microorganism. In this article evidence is presented showing that gluconic acid is also responsible for the antimicrobial activity of G. diazotrophicus PAL5. The broad antagonistic spectrum includes Grampositive and -negative bacteria. Eukaryotic microorganisms are more resistant to the growth inhibition by this acid. The inhibition by gluconic acid can be modified through the presence of other organic acids. In contrast to other microorganisms, the quorum sensing system of G. diazotrophicus PAL5, a regulatory mechanism that plays a key role in several microbe-microbe interactions, is not related to the gluconic acid production and the concomitant antagonistic activity.