Optimization of environmental conditions for the growth and bioaccumulation of As(III) and As(V) ions by growing Corynebacterium glutamicum MTCC 2745: inhibition kinetic study

The significant factors affecting simultaneously the growth and bioaccumulation of arsenic [As(III) and As(V)] ions by living cells of bacteria, Corynebacterium glutamicum MTCC 2745, were explored in growth media under various experimental environmental conditions such as pH, inoculum size, contact time, temperature, concentrations of peptone and arsenic [either As(III) or As(V)] ions. Three kinetic models namely competitive, noncompetitive and uncompetitive models were verified with the aim of deciding the toxic effects of arsenic on specific growth rate of C. glutamicum MTCC 2745. As(III) was observed to be more toxic than As(V). Competitive inhibition was found in either As(III) or As(V) systems which was suggested by almost same maximum specific growth rate ( µ m ) value and an increase in the saturation constant ( K ′ S,app ) value that were evaluated from Lineweaver–Burk plots. A simultaneous reduction in the inhibition constant recommended that inhibitory effect increases with the increase in arsenic concentration.