A study of methanol transport/uptake by a methanol-utilizing bacterium L3 in a batch bioreactor

Two novel, nitrogen-limited and oxygen-limited, perturbed transient experiments were performed to examine the presence of active transport of methanol and study the effect on methanol uptake by a methanol-utilizing bacterium, L3, in a batch bioreactor. Transient limitations of both ammonium ions and O(2) in batch cultures were found to cause methanol leakages out of the cells, suggesting the presence of an active transport of methanol in L3. Such experimental results were used to indirectly estimate the intracellular levels of methanol during a batch growth of L3. The results of our analysis indicate that the intracellular methanol level is high and show an increasing trend during the unbalanced phase, but falls to a constant low level in the balanced phase of a typical batch growth(8) of L3. A simple modelling analysis suggests that a four-parameter "pump-and-extrusion" model could be used to adequately describe the transport of methanol between the extra cellular and intracellular phases of batch cultures of L3.