Antarctic Peninsula environs as a source for new antimicrobials.

DANILOVICH M; SANCHEZ LA; ACOSTA F; ARNAU VG; DELGADO OD

Cordoba

Congreso; XI Congreso Argetino de Microbiologa General; 2015

Sociedad Argentina de Microbiologia General

Antarcticais the biggest pristine area on Earth and represents one of the most valuableenvironments due to its microbial diversity. It is indispensable to emphasizethe study of pristine natural extreme-ecosystems since numerous biologicallyactive compounds including antibiotics, pesticides, hormones, growth factors,antioxidants, biosurfactants and enzymes have been isolated from microorganismsbelonging to them. In the medicinal area, research and development of novelcompounds with antimicrobial activities have become a priority due to theincreased drug resistance in common bacterial pathogens along with theemergence of new pathogenicity. To deal with this situation, a value-increasingstrategy is on the spotlight: Bioprospecting.This process tends to directsearch for metabolites with biotechnological importance from microbial isolatesin natural environments with specific characteristics. Based on this premise,thirteen cold-adapted isolates from soil and water samples surroundingAntarctic Peninsula were studied for enzyme and antimicrobial production. Theability to produce biosurfactants was also tested. The enzymatic activitiesmost frequently found among the isolates were as follow: lipase (46%),cellulase (23%),amylase (7%) and gelatinase (13%). Biosurfactant production was detected in 46% ofthe isolates. Three isolates were able to inhibit the growth of commonfood-borne pathogen bacteria and also some phytopatogens. The isolates 2D, 5Dand 6D were closely related to Halomonastitanicae (99.8, 98.9, 96.7% respectively) by 16S rRNA gene sequencing. Theprofile of sugar was studied by the API 50 CHB system and other physiologicalcharacteristics by API 20NE systems and API 50CH. Growth rate at differenttemperatures, pHs and NaCl tolerance were determined. The significant influenceof culture media and incubation temperature on antimicrobial production wereevaluated, being LB-SW medium and 25°C the optimal conditions for antimicrobialproduction. Besides to marked tolerance to enzymatic treatment and negative netcharge at pH 8.0 during electrophoresis, the antimicrobial compounds showedwide inhibition spectrum against both, G-positive and G-negative pathogenic andphyto-pathogenic bacteria. The antagonist compounds were produced during the stationaryphase of growth and concentrated from cell-free supernatant by using SPE-C18cartridges. The significance of this work lies in valuing pristine environmentsbecause of their importance as new sources of bioactive compounds and theirpossible role in agricultural or pharmaceutical biotechnological industries.