Abstract: | Pathways and rates of metabolism of three 14C1-compounds (methanol, formaldehyde, and formic acid) were investigated by means of the heterogeneous population of activated sludge microorganisms. For the above microbial population formaldehyde was the primary or preferential substrate. During an hour aeration it was processed by activated sludge 6 times faster than by sodium formiate and 2 times faster than by methanol. The basic pathways of its transformation were oxidation via formiate to CO2 with its partial reutilization and direct incorporation into the sludge biomass via the primary formation of serine. An addition of methanol increased the incorporation of 14C-formadehyde into biomass and decreased the formation of free 14CO2. The main mechanism of the transformation of 14C-formiate in activated sludge was its oxidation to CO2. An addition of methanol and formaldehyde induced no essential changes in the rate or pattern of their metabolism. |