Production of β-(pyrazol-1-yl)-L-alanine from L-serine and pyrazol using recombinant Escherichia coli cells expressing serine acetyltransferase and O-acetylserine sulfhydrylase-A

beta -(Pyrazol-1-yl)-L-alanine ( beta -PA) was produced from L-serine and pyrazol using recombinant Escherichia coli cells expressing serine acetyltransferase and O-acetylserine sulfhydrylase-A. The amount of beta -PA increased with increasing L-serine concentrations up to 600 mM at 50 mM pyrazol while 100 mM pyrazol gave the highest beta -PA production with 50 mM L-serine. Under the optimized conditions, beta -PA accumulated in the broth at approximately 140 mM with a conversion of 90% with respect to the added amount of pyrazol.