Isolation, identification and characterization of a Hypocrea tawa strain with high Cr(VI) reduction potential

Abstract

A fungal strain that exhibits high Cr(VI) reduction potential was isolated from surface water by enrichment culture techniques. The isolated fungus was identified as Hypocrea tawa by the D1/D2 domain sequence of its 26S rRNA gene. The Cr(VI) reduction process catalyzed by H. tawa was characterized in batch cultures conducted at initial Cr(VI) concentrations ranging from 0.59 to 4.13 mM. The fungus showed a remarkable capacity to completely reduce very high concentrations of Cr(VI) (4.13 mM) under aerobic conditions. Higher volumetric (1.75 mg Cr(VI)/L h) and specific rates (0.67 mg Cr(VI)/g biomass h) as well as a greater capacity (77 mg Cr(VI)/g biomass) to reduce Cr(VI) were obtained with higher initial Cr(VI) concentrations (4.13 mM), which suggests that the fungal strain could be potentially useful for detoxification of Cr(VI)-laden wastewaters.