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

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