Presence of endophytic diazotrophs in sugarcane juice

Abstract

In this work we investigated the diazotrophs present in the juice of different varieties of sugarcane. Samples of the aerial part of sugarcane, between 3 and 5 months old, were assessed for the presence of diazotrophs. The isolated nitrogen-fixing microorganisms were identified as Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae and Azospirillum brasilense. These microorganisms use organic acids found in the sugarcane juice as an energy source. They also use sugars, such as free glucose, that are present in all the organs of the aerial part. The distribution of endophytic microorganisms in sugarcane depends on the different organic acid and sugar concentrations present during development and growth. We concluded that in more mature regions of the sugarcane stem Gluconacetobacter diazotrophicus grows more abundantly than Herbaspirillum seropedicae or Azospirillum brasilense.