PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
artículos
Título:
Critical influence of culture medium and Cr(III) quantification protocols on the interpretation of Cr(VI) bioremediation by environmental fungal isolates
Autor/es:
FERNÁNDEZ P,; CASTELLANOS DE FIGUEROA, LUCÍA INÉS; FARIÑA J.I.
Revista:
WATER AIR AND SOIL POLLUTION
Editorial:
Springer-Verlag GmbH
Referencias:
Lugar: Heidelberg, Germany; Año: 2008 p. 1 - 1
ISSN:
0049-6979
Resumen:
Abstract: The influence of culture medium
composition on the chromium(VI) quantification according to the
diphenylcarbazide (DPC) colorimetric determination was evaluated. Considering
the eventual biospeciation of Cr(VI) as a mechanism of microbial bioremediation,
the possibility to quantify Cr(III) in culture medium was also explored. Yeast
Nitrogen Base (YNB) was identified as the least interferent culture medium for
Cr(VI) quantification by DPC and it was applied to compare different strategies
for Cr(III) oxidation. The most appropriate oxidation protocol consisted in the
reaction with 80 mM
KIO4 at room temperature for 30 min prior to DPC. Parameters like basal culture
medium (vitamins + salts + oligoelements), C- and N-source were systematically
evaluated, either independently or in combination. Results demonstrated that
C-source was the most interferent culture medium component, being the use of
sucrose preferable to glucose. A medium arbitrarily named as YNB' (YNB w/o
aminoacids and ammonium sulfate plus 50 g l-1 sucrose and 0.6 g l-1 (NH4)2SO4) was
defined for Cr(VI)-amended fungal cultures. Kinetics of growth, Cr(VI) removal
and nutrient consumption for isolates A. pullulans VR-8, filamentous fungus
PMF-1, and Lecythophora sp. NGV-1 were obtained. The order of Cr(VI)-removal
efficiency was as follows: A. pullulans VR-8 Lecythophora sp. NGV-1 filamentous
fungus PMF-1, and a similar trend was observed for biomass yield and nutrients
consumption. Studies on biospeciation by means of the selected Cr(III)
oxidation protocol were unsuccessful, leading to Cr(VI) values much lower than
expected. It revealed that this kind of protocols should be cautiously
evaluated when studying microbial Cr(VI) bioremediation.