Abstract

LARA-SEVERINO, Reyna del Carmen et al. SEARCHING FOR THE BIOSURFACTANT PRODUCTION CAPACITY OF HALOALKALIFILIC AND HALOALKALITOLERANT ACTINOBACTERIA. Rev. Int. Contam. Ambient [online]. 2017, vol.33, n.3, pp.529-539. ISSN 0188-4999.  https://doi.org/10.20937/rica.2017.33.03.15.

One option for bioremediation of saline environments contaminated with hydrophobic organic compounds is the use of haloalkaliphilic or haloalkalitolerant microorganisms capable of producing stable biosurfactants and consuming the hydrophobic compound. The biosurfactant solubilizes the contaminant making it bioavailable for the microorganism. Previous studies have revealed the ability to transform anthracene from seven haloalkalitolerant actinobacteria. In this work the ability to produce biosurfactants with emulsifying properties from these seven plus 11 isolates of saline environments were determined. Those that showed the capability were investigated for anthracene as their only source of carbon and energy. The ability to produce biosurfactant was determined by methods of hemolytic activity, collapsed droplet and diffusion of droplet diameter. The emulsifying property and the stability of the emulsion were characterized by the emulsification index and the relative emulsification index, respectively. Of 18 actinobacteria evaluated, five strains showed capacity to produce biosurfactants with emulsifying properties, high stability in the emulsion and the use of anthracene as their only source of carbon and energy. Of these five strains, two are haloalkaliphilic, they belong to the species Nocardiopsis salina and three are haloalkalitolerant, they belong to the species Kocuria palustris, Microbacterium testaceum and Kocuria rosea. In a previous study the transforming capacity of anthracene of the three haloalkalitolerant strains was determined; therefore the results of this study suggest they can be proposed as candidates for bioremediation processes of saline environments contaminated with hydrophobic compounds. Likewise it is also recommended to determine the same capacity for the two haloalkaliphilic strains.

Keywords : bacteria; emulsifier; surfactant; contamination; bioremediation.