Gluconic acid produced by Gluconacetobacter diazotrophicus PAL5 possesses antimicrobial properties

CARLOS G. NIETO PEÑALVER; MARÍA JULIETA SAVINO; ELISA V. BERTINI; LEANDRO SÁNCHEZ; LUCÍA I. CASTELLANO DE FIGUEROA

RESEARCH IN MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; 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 direct oxidation of glucose by a pyrroloquinoline-quinone-linked glucose dehydrogenase in this plant growth-promoting bacterium. In the present article, evidence is presented showing that gluconic acid is also responsible for the antimicrobial activity of G. diazotrophicus Pal5. The broad antagonistic spectrum includes Gram-positive and -negative bacteria. Eukaryotic microorganisms are more resistant to growth inhibition by this acid. Inhibition by gluconic acid can be modified through the presence of other organic acids. In contrast to other microorganisms, the QS system of G. diazotrophicus Pal5, a regulatory mechanism that plays a key role in several microbe-microbe interactions, is not related to gluconic acid production or concomitant antagonistic activity.