Chromium (VI) bioremediation at various environmental conditions using chromate-resistant yeasts

FERNÁNDEZ, PABLO M; MARTORELL, MARÍA M.; FIGUEROA, LUCÍA I. C.; FARIÑA, JULIA I.

SAN MIGUEL DE TUCUMAN, TUCUMAN, ARGENTINA

Congreso; XLV Reunión Anual SAIB,; 2009

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Contamination by chromium compounds is caused by a variety of industrial applications eventually leading to heavy pollution of soil, surface water and atmosphere. Two chromium resistant yeast strains, Pichia jadinii and Pichia anomala, converting toxic Cr(VI) to the less toxic and immobile Cr(III), were evaluated at different culture conditions in order to optimize heavy metal removal. Cultures were carried out in YNB medium supplemented with sucrose and ammonium sulfate during 120 h. The influence of Cr(VI) initial concentration, temperature and agitation conditions on Cr(VI) detoxification were evaluated. For both yeast strains biomass production and Cr(VI) removal was positively affected by increasing incubation temperature (up to 30ºC) and under shaken culture conditions (up to 250 rpm). Complete Cr(VI) disappearance was retarded as initial Cr(VI) concentration increased. Whilst at 0.5 mM strains were able to completely remove Cr(VI) within 12 and 8 h of incubation, at 2 mM, full removal required 96 and 72 h, for P. jadinii and P. anomala respectively. These optimized parameters would be applicable at fermentor scale in order to perform a succesful Cr-removal potentially valuable for bioremediation purposes.