Isolation of methane monooxygenase-deficient mutants from Methylosinus trichosporium OB3b using dichloromethane

Stable mutants deficient in methane monooxygenase enzymic activity were isolated from the obligate methylotroph Methylosinus trichosporium</it> OB3b using dichloromethane in the selection procedure. This was based on the ability of methane monooxygenase (MMO) to cooxidise dichloromethane into carbon monoxide creating lethal conditions for the ‘wild type’ cells. Furthermore, additional properties associated with dichloromethane the selective agent itself, as its mutagenic action and its apparent permeability into M. trichosporium</it> OB3b cells have contributed in the successful isolation of MMO-deficient mutants.