ANTARCTIC PENINSULA ENVIRONS AS A SOURCE FOR NEW ANTIMICROBIALS

DANILOVICH, MARIANA ELIZABETH; SÁNCHEZ, LEANDRO ARTURO; ACOSTA, FEDERICO; ARNAU, VÍCTOR GONZALO; DELGADO, OSVALDO DANIEL

Córdoba

Congreso; XI CONGRESO ARGENTINO DE MICROBIOLOGIA-SAMIGE; 2015

Asociación Argentina de Microbiología

Antarctica is the biggest pristine area on Earth and represents one of the most valuable environments due to its microbial diversity. It is indispensable to emphasize the study of pristine natural extreme-ecosystems since numerous biologically active compounds including antibiotics, pesticides, hormones, growth factors, antioxidants, biosurfactants and enzymes have been isolated from microorganisms belonging to them. In the medicinal area, research and development of novel compounds with antimicrobial activities has become in a priority due to the increased drug resistance in common bacterial pathogens along with the emergence of new pathogenicity. To deal with this situation, a value-increasing strategy is on the spotlight: Bioprospecting. This process tends to direct search for metabolites with biotechnological importance from microbial isolates in natural environments with specific characteristics.Based on this premise, thirteen cold-adapted isolates from soil and water samples surrounding Antarctic Peninsula were studied for enzyme and antimicrobial production. The ability to produce biosurfactants was also tested.The enzymatic activities most frequently found among the isolates were as follow: lipase (46%), cellulase (23%), amylase (7%) and gelatinase (13%). Biosurfactant production was detected in 46% of the isolates. Three isolates were able to inhibit the growth of common food-borne pathogen bacteria and also some phytopatogens. The isolates 2D, 5D and 6D were closely related to Halomonas titanicae (99.8, 98.9, 96.7% respectively) by 16S rRNA gene sequencing. The profile of sugar was studied by the API 50 CHB system and other physiological characteristics by API 20NE systems and API 50CH. Growth rate at different temperatures, pHs and NaCl tolerance were determined. The significant influence of culture media and incubation temperature on antimicrobial production were evaluated, being LB-SW medium and 25°C the optimal conditions for antimicrobial production. Besides to marked tolerance to enzymatic treatment and negative net charge at pH 8.0 during electrophoresis, the antimicrobial compounds showed wide inhibition spectrum against both, G-positive and G-negative pathogenic and phyto-pathogenic bacteria. The antagonist compounds were produced during stationary phase of growth and concentrated from cell-free supernatant by using SPE-C18 cartridges. The significance of this work lies in valuing pristine environments because of their importance as new sources of bioactive compounds and their possible role in agricultural or pharmaceutical biotechnological industries.