The Production of L ‐serine with a methylotrophic microorganism using the L ‐serine pathway and coupling with an L ‐tryptophan‐producing process

The cultural conditions for the production of enhanced formation of L‐serine (up to 7 g/L) are described with the methylotrophic bacterium Pseudomonas 3 ab (DSM 672). The batch process is divided into three parts: (1) the biomass production phase, (2) substrate limitation period, and (3) L‐serine accumulation phase. The initial specific production rate of q p = 0.1 g L‐serine/g dry wt/h is based on the inhibition of the L‐serine pathway. This is accomplished by high precursor concentrations (glycine) and a pH shift to pH 8.5. The enzymatic background is discussed. Furthermore, a coupling of the L‐serine process with a L‐tryptophan‐producing process is demonstrated.