DEHALOGENATION OF HALOALKANES BY RHODOCOCCUS-ERYTHROPOLIS Y2

Rhodococcus erythropolis Y2 produced two types of dehalogenase: a hydrolytic enzyme, that is an halidohydrolase, which was induced by C-3 to C-6 1-haloalkane substrates, and at least one oxygenase-type dehalogenase induced by C-7 to C-16 1-haloalkanes and n-alkanes. The oxygenase-type activity dehalogenated C-4 to C-18 1-chloroalkanes with an optimum activity towards 1-chlorotetradecane, The halidohydrolase catalysed the dehalogenation of a wide range of 1- and alpha,omega-disubstituted haloalkanes and alpha,omega-substituted haloalcohols. In resting cell suspensions of hexadecane-grown R. erythropolis Y2 the oxygenase-type dehalogenase had a specific activity of 12.9 mU (mg protein)(-1) towards 1-chlorotetradecane (3.67 mU mg(-1) towards 1-chlorobutane) whereas the halidohydrolase in 1-chlorobutane-grown batch cultures had a specific activity of 44 mU (mg protein)(-1) towards 1-chlorobutane. The significance of the two dehalogenase systems in a single bacterial strain is discussed in terms of their contribution to the overall catabolic potential of the organism.