Evaluation of the Potential of Biosurfactant Production by Bacillus Strains in Different Culture Media

Evaluation of the potential of biosurfactant production by Bacillus strains in different culture media

Darlane Wellen Freitas de Oliveira, Ítalo Waldimiro Lima de França, Diana Pereira Bezerra, Vânia Maria Maciel Melo, Luciana Rocha Barros Gonçalves^*

Universidade Federal do Ceará, Department of Chemical Engineering, Av. Mister Hull, 2977, Block 709 – Campus do Pici – Zip-code  60.455-760, Fortaleza,  Brazil

* lrg@ufc.br

 

Biosurfactants are surface-active molecules synthesized by microorganisms and have
advantages as biodegradability, more ecological acceptance, greater structural diversity and
low toxicity to the environment when compared to synthetic surfactants. The greatest challenge in producing biosurfactants is to develop a bioproduct economically compatible with the synthetic surfactan. In this study, the potential in producing biosurfactant by Bacillus subtilis Jag 248, a strain that was selected from the collection of bacteria belonging to the Laboratory of Microbiology and Immunology, Federal University of Ceará, was evaluated. Three different culture mediums were studied: clarified cashew apple juice, mineral medium and mineral medium supplemented with a solution of micronutrients. When Bacillus subtilis Jag 248 was grown in clarified cashew apple juice, surfactin and biomass concentrations around 27.0 mg.L^-1 and 1.0 g.L^-1 were achieved, respectively. On the other hand, when mineral medium was used, surfactin and biomass concentration was 161.0 mg.L^-1 and 1.5 g.L^-1, respectively.  Furthermore, the supplementation of mineral medium with a solution of micronutrients did not enhance biomass concentration, that was around 1.3 g.L^-1. Regarding substrate consumption, a significant amount of residual carbon was observed when B. subtilis Jag 248 was cultivated in clarified cashew apple juice. On the contrary, the strain consumed the carbon source present in  in mineral medium after 20 hours of culture. The surface tension of all mediums was reduced up to 29.0 dyna.cm^-1, which indicates biosurfactant production. The pH of all media studied was between 6.0 and 7.0. These results show that the strain evaluated in this work is a potential biosurfactant producer and further experiments will be performed in order to optimize production.