Crescimento e descrição morfológicas das Acidobactérias AB46 e AB29

Abstract

The Cerrado is Brazil’s second-largest biome, boasting a rich microbial biodiversity and exhibiting diverse survival mechanisms. Among these microorganisms are acidobacteria, which are capable of producing compounds of industrial interest. Despite this, they are difficult to culture, with only a small number of species that can be cultured and have been taxonomically described. The objective of this study was to evaluate the growth and morphology of acidobacteria AB46 and AB29 on different carbon sources and to compare them with other previously characterized acidobacteria obtained from Cerrado soil. To this end, the morphologies of the cells and colonies were described, and growth was monitored by the formation of colony-forming units over a 20-day period in VL-55 medium supplemented with one of the following carbon sources: xylan, xylose, cellobiose, and lactose. The results demonstrated that AB29 is a coccobacillus-shaped bacterium that forms white, mucous colonies. Growth of this strain was observed in all media containing different carbon sources, with celobiose being particularly prominent during the first six days. Strain AB46 exhibited typical Gram-positive staining, a result not consistent with all other members of the phylum Acidobacteriota, furthermore, the pink staining typical of carotenoid-producing acidobacteria was not observed on all plates, indicating culture contamination. Thus, the AB29 strains appear to be distinct from the other previously characterized acidobacteria strains from Cerrado soil, and the results for the AB46 strain were incomplete due to contamination.