Effect of formaldehyde on growth of obligate methylotroph Methylobacillus flagellatum in a substrate non-limited continuous culture

The ribulose monophosphate cycle methylotroph Methylobacillus flagellatum was grown under oxyturbidostat conditions on mixtures of methanol and formaldehyde when added at low concentration (50 mg/l) increased the methanol consumption and the yield of biomass. The presence of 150-300 mg/l of formaldehyde resulted in an increase of the growth rate from 0.74 to about 0.79-0.82/h. The presence of 500 mg/l of formaldehyde in the inflow decreased cultured growth characteristics. Activities of methanol dehydrogenase and enzymes participating in formaldehyde oxidation and assimilation were measured. The enzymological profiles obtained are discussed.