In methanol-limited continuous cultures of the obligate methylotrophic bacterium Methylobacillus flagellatum grown at rates from 0.05 to 0.63 h-1, and also in an oxyturbidostat culture of M. flagellatum growing at the rate of 0.73 h-1, levels of methanol dehydrogenase, enzymes of formaldehyde oxidation (both linear and cyclic) and assimilation (RuMP cycle), a number of intermediary metabolism and TCA cycle enzymes and also 'dye-linked' formaldehyde dehydrogenase were determined. It was shown that the activities of dissimilatory enzymes, with the exception of 'dye-linked' formaldehyde dehydrogenase, decreased with increasing growth rate. Activities of assimilative enzymes and activities of the TCA cycle enzymes detected as well as the 'dye-linked' formaldehyde dehydrogenase activity, increased with increasing growth rate. A periplasmic location was shown for the latter enzyme and a role in formaldehyde detoxification was proposed.

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The growth characteristics of a chemostat culture of the obligate methylotrophic bacterium Methylobacillus flagellaturn have been determined. Steady-state cultures growing at a rate of 0.73-0.74 h-', equal to the maximal growth rate, were obtained under oxyturbidostat cultivation conditions. The response of a chemostat culture to a pulse increase of methanol concentration was studied. It was shown that slow and rapidly growing cultures of M. flagellaturn responded differently to pulse methanol addition. The growth characteristics of slow-growing cultures decreased after methanol addition compared to those of stationary chemostat cultures. The growth characteristics of rapidly growing cultures were practically unchanged with and without pulse methanol addition.

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