EXPLORING THE MULTIPLE BIOTECHNOLOGICAL POTENTIAL OF HALOPHILIC MICROORGANISMS ISOLATED FROM TWO ARGENTINEAN SALTERNS.

NERCESSIAN, D.; DI MEGLIO, L.G.; DE CASTRO, R.; PAGGI, R. A.

Córdoba

Congreso; XI Congreso argentino de microbiología general.; 2015

Sociedad argentina de microbiología general

The biotechnological microbial potential of two salterns from La Pampa, Argentina has been explored . Salitral Negro and Colorada Grande are neutral hypersaline basins commercially exploded for NaCl extraction. Several microorganisms were isolated from water samples and screened for hydrolytic activities and bioactive molecules. Pure isolates were identified by sequencing a PCR-generated fragment of the 16S rRNA gene. Seven representatives of Archaea and two from Bacteria were obtained and screened for the presence of lipolytic and cellulolytic activities, as they are interesting enzymes for industrialapplication. Microorganisms were grown on SW agar medium supplemented with olive oil, Tween 20 and Tween 80 as source of triacylglycerols and esters of lauric or oleic acids. Tweens also allow testing the enzyme preference for saturated or un-saturated fatty acids. Har. argentinensis, Har. japonica and Salicola sp. degraded all the substrates while Har. vallismortis only hydrolysed olive oil and the un-saturated fatty acids contained in Tween 80. This observation suggests that the activities detected in Har. argentinensis, Har. japonica, Har. vallismortis and Salicola sp. may be attributed to different enzymes (lipaseand esterase) or by an extracellular lipase exhibiting both activities. The activities detected in Hbt. piscisalsi and Hrr. tebenquichense only with both Tweens may correspond to an extracellular esterase since they failed to degrade olive oil. The assay for cellulolytic activity suggested that Salicola sp., Har. vallismortis and Hbt. piscisalsi degraded CMC (carboxymethyl cellulose). The occurrence of biosurfactants was tested by emulsifying assays using cell-free culture media of the isolates. Olive oil and xylenes were used as substrate and SDS and Triton X-100 as positive controls. Har. japonica, Har. vallismortis, Hbt. piscisalsi and Salicola sp. produced surfactants that emulsified both aromatic compounds and long chain hydrocarbons whereas those synthesized by S. ruber, Har. argentinensis, Hbt. salinarum and Hrr. tebenquichense or Halobacterium sp. specifically emulsified long chain hydrocarbons or aromatic compounds respectively. To search for antimicrobial compounds each microorganism was tested against each other and growth inhibition was analyzed by the presence of halos on agar plates. Bacterial isolates were resistant to the archaeal isolates and vice versa, indicating that no inter-domain interaction existed. Har. argentinensis and Har. japonica were the most effective producers inhibiting growth of most archaeal isolates whereas Hrr. tebenquichense was the most sensitive strain. These results show the potential of halophilic microorganisms inhabiting Argentinian salterns, reinforcing the idea of screening extreme environments as a source of potentially novel and useful molecules.