
Full text loading...
Three bacterial cultures, the Gram-negative strain AD1 and the Gram-positive strains AD2 and AD3, were isolated from freshwater sediment after enrichment with epichlorohydrin as sole carbon source. In batch cultures of strain AD1 and strain AD3, epichlorohydrin was rapidly degraded to 3-chloro-l,2-propanediol. Crude extracts of strain AD1 contained epoxide hydrolase activity towards epichlorohydrin, epibromohydrin, glycidol and propylene oxide as substrates. In contrast, strain AD2 did not actively convert epichlorohydrin but utilized 3-chloro-l,2-propanediol produced by slow chemical hydrolysis. No epichlorohydrin epoxide hydrolase was found in extracts of this organism. Crude extracts of strains AD1 and AD2 dehalogenated a number of mono- and dihalogenated alcohols and ketones, such as 1,3-dichloro-2-propanol, 3-chloro-l,2-propanediol, l-chloro-2-propanol, l,3-dibromo-2-propanol, chloro-acetone and 1,3-dichloroacetone. Dehalogenation yielded epoxides as products. The results suggest that epichlorohydrin is converted by strain AD1 via 3-chloro-l,2-propanediol and glycidol by the action of an epoxide hydrolase and a dehalogenase, respectively. The same route for dehalogenation proceeds in strain AD2, which, however, is dependent on chemical hydrolysis of epichlorohydrin rather than enzymic conversion.