COPPER RESISTANCE IN Pseudomonas extremaustralis AND ITS RELATIONSHIP WITH POLYHYDROXYALKANOATES ACCUMULATION

ANTONELA COLONNELLA; CARLA DI MARTINO; NANCY I. LOPEZ; LAURA J. RAIGER IUSTMAN

Mar del Plata

Congreso; X Congreso Argentino de Microbiologia General SAMIGE 2014; 2014

SAMIGE

Copper is an essential micronutrient, critical for cell function. However at high concentrations copper tends to accumulate in soils, plants and animals, increasing its harmful effects within superior levels of food chains. There are different process for removal of Cu(II) from wastewater and soils, including precipitation, ion-exchange, evaporation, oxidation, electroplating and membrane filtration. But application of such technologies has technical or economic constraints. Bioremediation, an environmental friendly and cheap approach, was proposed to access the cleanup these sites. One of bioremediation mechanisms involve the seeding of microorganisms with known ability to transform or to adsorb the contaminant (bioaugmentation), but success also depends on the adaptability of the microorganism to the stressing environment. Pseudomonas extremaustralis was isolate from a temporary pond in Antarctica and shows high resistance to several stresses in association with the production of polyhydroxyalkanoates (PHAs). The genome analysis of P. extremaustralis exhibited the presence of several sequences that could be involved in copper resistance like: several cytochrome oxidases, 5 copies of a Type P Cu-translocation system (homologous to CopAB) and an efflux system CusAB. Copper minimum inhibitory concentration (Cu(II) CIM) was assayed using LB broth 0.5X supplemented with glucose 2% (PHA accumulation conditions) and different concentrations of CuSO4 (1mM-5mM). As PHAs enhance stress resistance, a phaC1ZC2 mutant was also assayed. Cu(II) CIM was the same for both strains (2mM), so PHA seems to have no effect on copper resistance. Biosorption is an strategy used by microorganisms to cope with high Cu(II) concentration. P. extremaustralis 14-3 and its pha mutant?s sorption capacity were examined. In order to describe Cu(II) biosorption characteristics, Langmuir and Freundlich models were evaluated. Wild type strain´s Cu biosorption was higher than the mutant, although both strains adjust to Freundlich model.