The growth dynamics of a methanol‐utilizing bacterium L3 in a batch bioreactor

Abstract

The growth dynamics of a methanol utilizing bacterium, L3, in batch bioreactors were experimentally investigated. Formaldehyde, a key intermediate of methanol oxidation, is indicated to have a significant role in the complex batch growth behavior of L3. The intricate batch growth dynamics of many microorganisms can be elegantly characterized by examining the specific rates of exchange of nutrients and products between the cells and the cellular environment. Following such an analysis, the batch growth of L3 on methanol was characterized by the presence of unbalanced and balanced growth phases. The nature and significance of nutrient and product concentration profiles or semilog-arithmic profiles of nutrient and product exchange rates during balanced and unbalanced growth phases are also outlined.

Cultivation of methanotrophic bacteria in opposing gradients of methane and oxygen

“…Thus, it is not surprising that formaldehyde is accumulated by methaneoxidizing bacteria under excess supply with methane and oxygen, and this was found also with our strain LC 2 during growth on solid medium plates. So far, formaldehyde production (0.2-7 mM) by methanotrophs was reported only during growth at high methanol and oxygen concentrations (Agrawal & Lim, 1984;Costa et al, 2001). Formaldehyde becomes inhibitory at concentrations between 1 mM (Hou et al, 1978) and 7 mM (Costa et al, 2001).…”

“…Intermediates of methane oxidation, such as methanol, formaldehyde and formate, have been detected in methanotrophic cultures, and they may even reach inhibitory concentrations (Agrawal & Lim, 1984;Costa et al, 2001). The production of formaldehyde and formate is favoured under unbalanced growth conditions if such bacteria are grown with methanol at high concentrations of oxygen.…”