Bioprospecção da atividade antimicrobiana do caldo de fermentação produzido pelo endofítico Paenibacillus terrae isolado de Tabebuia spp. do Cerrado em co-cultivo com Bacillus thuringiensis e Bacillus megaterium

Abstract

As the second largest Brazilian biome, the Cerrado is classified as a “hot spot” for its several endemic species and the great threat of territorial loss, but its biodiversity is still little known. In this biodiversity there are endophytic microorganisms, which are in focus for acquisition and production of secondary metabolites, due to the biotechnological potential identified in them. The present study sought to evaluate the antibacterial and antifungal potential of Paenibacillus terrae, an endophytic isolated from Tabebuia spp., and also its activity in co-culture with Bacillus thuringiensis and Bacillus megaterium, seeking greater bioactivity. For the microorganisms tested, inhibition halos (mm) of 8.6, 9.4 and 11.4 were detected for Escherichia coli, Staphylococcus aureus and Candida albicans, respectively. Against Bacillus thuringiensis and Bacillus megaterium, no inhibition was detected, probably due to selective inhibition. Paenibacillus terrae showed better results when co-cultivated with Bacillus megaterium, against E. coli and S. aureus, with halos of 10.6 and 9.5 mm, respectively. On the other hand, the co-culture with B. megaterium, against C. albicans, there was no inhibition. The same happened with the tests of co-culture of P. terrae with B. thuringiensis, against all tested microorganisms. These results should indicate a greater selective pressure among the microorganisms tested, generating the presence of inhibition halos. The action of Paenibacillus terrae was tested in relation to selected antibiotics, amikacin, ampicillin, carbenicillin, cephalothin, cefepime, clindamycin, chloramphenicol, erythromycin, gentamicin, nitrofurantoin, oxacillin, sulfazotrim, teicoplanin, and tetracycline the greatest inhibitory potentials were against sulfazotrim, chloramphenicol and amikacin, with 37.3, 31.0 and 22.25 mm of inhibition. Carbenicillin, cephalothin, clindamycin and oxacillin did not inhibit. The data obtained are similar to other works and also indicate the permanence of microbial susceptibility to most of the tested antibiotics. The bioprospecting of endophytes is essential for the search for bioactive metabolites since the production of biomolecules can contribute as biocontrol agents, microbial and parasitic inhibition, as anti-inflammatories and in industry, pharmacy, medicine and biotechnology.