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Aerobic Cr(VI) reduction by Thermus scotoductus strain SA‐01
Author(s) -
Opperman D.J.,
van Heerden E.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2007.03429.x
Subject(s) - thermus , strain (injury) , reduction (mathematics) , microbiology and biotechnology , biology , chemistry , bacteria , genetics , mathematics , thermophile , anatomy , geometry
Aim: To evaluate Thermus scotoductus SA‐01’s ability to reduce Cr(VI) aerobically. Methods and Results: T. scotoductus SA‐01 is able to reduce Cr(VI) aerobically when grown in a complex organic medium containing Cr(VI) concentrations up to 0·5 mmol l −1 . Suspension of T. scotoductus SA‐01 cells also reduced Cr(VI) aerobically under nongrowth conditions using a variety of electron donors as well as in the absence of an exogenous electron donor. The optimum temperature and pH for Cr(VI) reduction under nongrowth conditions were found to be 80°C and 7, respectively. It was also found that the Cr(VI) reduction was catalysed by a cytoplasmic, constitutively expressed enzyme. Conclusions: Apart from SA‐01’s ability to reduce Cr(VI) through a strictly anaerobic membrane‐bound mechanism (unpublished data), it also has a second enzyme localized in the cytoplasm that can reduce Cr(VI) aerobically. As this enzyme is constitutively expressed and not induced by Cr(VI), it remains to be determined whether it has any other physiological functions. Significance and Impact of the Study: This is the first report of a Thermus species able to reduce Cr(VI) aerobically and extends the knowledge of parameters associated with Cr(VI) reduction. Employing thermophiles in bioremediation using industrial bioreactors would cancel the need for expensive cooling systems.