Chloromethane stimulates growth of Methylomicrobium album BG8 on methanol

Studies were performed to determine if the growth of Methylomicrobium album BG8 on methanol could be enhanced through the provision of chloromethane. M. album BG8 was found to be able to oxidize chloromethane via the particul ate methane monooxygenase with an apparent K-s of 11+/-3 mu M and V-max of 15+/-0.6 nmol (min mg protein)(-1). When up to 2.6 mM chloromethane was pro vided with 5 mM methanol, methanotrophic growth was significantly enhanced in comparison to the absence of chloromethane, indicating that methanotroph s can utilize chloromethane to support growth, although it could not serve as a sole growth substrate. [C-14]chloromethane was found to be oxidized to [C-14]CO2 as well as incorporated into biomass. These results indicate tha t reactions previously thought to be cometabolic may actually provide some benefit to methanotrophs and that these cells can use multiple compounds to enhance growth. (C) 2000 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.