PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
THE FIGHT AGAINST PATHOGENS IS NOT OVER: ARGENTINE ANTARCTIC EXPEDITIONS DISCLOSE A NOVEL SOURCE FOR COLD - ACTIVE ANTIMICROBIAL BIOPROSPECTING
Autor/es:
DANILOVICH, M.E; ACOSTA, F.; SANCHEZ L. A,; DELGADO O.D.
Lugar:
Mar del Plata
Reunión:
Congreso; X CONGRESO ARGENTINO DE MICROBIOLOGIA GENERAL SAMIGE; 2014
Institución organizadora:
Sociedad Argentina de Microbiología General SAMIGE
Resumen:
An organism that lives in an extreme environment
is an extremophile. Within extremophiles we can find organisms belonging to
archaea, prokaryotes and eukaryotes. Key factors, such as frequent and inappropriate
use of antibiotic causing increase in bacterial resistance to those commonly
used, as well as an irregular emergence generated from a detriment of
pharmaceutical companies involved in drugs discovery, makes the development of
new antibiotics is a growing worldwide problem and a constant challenge. The need to reduce additives in food industry has triggered the pursuit
of natural antimicrobial substances produced by microorganisms from different
sources with the aim of preserving processed foods by inhibiting microorganisms
associated with food-borne illness. Most antibiotics emerged from screening
programs of natural sources, including the isolation of new microorganisms,
modification of well-known producers or metabolic engineering of fermentation
processes. Extremophiles are considered an important source
of metabolites, enzymes and bio-products since they are adapted to their
unusual living conditions. This work focused on
the isolation of psychrotolerant and psychrophilic microorganisms producing
cold-active substances with the ability to inhibit the growth of common
food-borne pathogens and phytopatogens for potential use in food preservation,
pharmaceutical industry or as agriceutical. Twenty-seven antimicrobial
producers were isolated by using microbiological selection techniques from sea
water and sediment samples obtained during the 2011 and 2014 summer Antarctic campaigns of the oceanographic
survey ship ARA Puerto Deseado. Isolates were grouped
in 11 OTUs by ITS-ARDRA techniques; four of them were selected for
identification based on rDNA regions sequence analysis together with the
biochemical characterization. Isolates 2D, 5D and 6D were closely related to Halomonas titanicae (99.8, 98.9, 96.7%
respectively), whilst isolate 18SH was related to Candida sake (99%). Antimicrobials produced by isolates 2D, 5D and
6D exhibited low molecular weight (<6,000 Da) and inhibition spectrum
against both, Gram (+) and Gram (-) pathogenic bacteria. The antagonist
compound produced by Candida sake
18SH showed a higher molecular weight (˃12,000 Da) and a narrower spectrum of
bacterial inhibition. However, antagonistic activity against fungi causing rots
in fruits was detected. Due to its potential as plant pathogen biocontrol agent
was selected for further characterization. Studies indicate antimicrobial
stability in 5.0-7.0 pH range and 4-45°C temperature range. Antimicrobial
activity was detected during early stationary growth phase retaining
antimicrobial activity at low temperatures. To purify the antimicrobial, a
protocol involving solid-phase C18 cartridges and HPLC was developed. This work highlights cold environments as a suitable source of
microorganisms with the ability to produce cold-active biomolecules of
biotechnological interest.