ISSN:
1573-0972
Keywords:
Enterobacter cloacae
;
metal reduction
;
molybdenum reductase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract Under anaerobic conditions in glucose–yeast extract medium with phosphate, Enterobacter cloacae strain 48 grew well and reduced Mo6+, to Mo5+. The activity of Mo6+-reductase was measured by the formation of molybdenum blue (complexation between Mo5+ and phosphate ion). Models based on logistic and Luedeking–Piret equations were found adequate to describe the growth of E. cloacae and Mo6+-reductase production. Mo6+-reductase production was found to be a growth-associated process. Washed intact cells, membrane fraction (after disruption using a sonicator) and fluid supernatant (after cell disruption) were able to reduce Mo6+. However, Mo6+-reductase activity was much lower in the supernatant fluid. The (NH4)2SO4-precipitated Mo6+-reductase extract from fluid supernatant was assayed for its properties. The optimum pH and temperature for Mo6+-reductase activity were 8 and 30°C, respectively. The apparent Michaelis–Menten constant (Km) and a maximum velocity (Vmax) were 16.5mm and 0.0192μmol/ml.h, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1018562719751
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