REGULATION OF METABOLISM IN THE FACULTATIVE METHYLOTROPHS. Oleg Mosin Department of Biotechnology. M.V. State Academy of fine Chemical Technology, Moscow. Fultative methylotrophs can be found abundantly among methylotrophic organisms employing the Calvin cycle, the serine pathway, or the XuMP cycle for the assimilation of C1-compounds (O.

Mosin, 1998). It is only in recent years, however, that scientists have succeeded in the isolation of a number of versatile RuMP cycle bacteria. These facultative RuMP cycle methylotrophs are found almost exclusively among Gram-positive bacteria. Representatives are various bacilli, coryneform bacteria, and actinomycete species (Dijkhuizen et al 1992; Dijkhuizen, 1993). Most of these methylotrophs grow on methylated amines and

only few use methanol as sole carbon- and energy source for growth. Currently scientists are engaged in a detailed physiological, biochemical and genetic analysis of pathways of primary metabolism in the actinomycetes. These bacteria are a very versatile methanol-utilizing organisms, employing the fructose-bisphosphate aldolase cleavage variant of the RuMP cycle of formaldehyde fixation (Hazeu et al 1983; de

Boer et al 1990). Llittle is known at the moment about primary metabolism in actinomycetes. Over the years attention of scientisys has been devoted to the analysis of the genetics of pathways for secondary metabolite synthesis, and the screening and testing for new applications of the enormous variety of secondary metabolites (e.g. antibiotics) produced by many actinomycetes (L. Dijkhuizen, 1998). Secondary metabolites, however, are derived from intermediates of central metabolic