A photo/biocatalytic system for visible-light driven l-alanine production from ammonia and pyruvate†

The chemical structure of L-alanine is similar to that of L-lactic acid and its polymerisation product, poly(L-alanine) (poly-L-Ala), is a biodegradable nylon. There is a need for a method capable of synthesizing L-alanine, a monomer of poly-L-Ala, from a biobased material with a renewable energy source. In this work, visible-light driven L-alanine from biobased material pyruvate and ammonium ions with a system consisting of triethanolamine, water-soluble zinc porphyrin, pentamethylcyclopentadienyl coordinated rhodium complex, NAD⁺ and L-alanine dehydrogenase from Bacillus subtilis is established. In particular, the conversion yield for pyruvate to L-alanine was improved up to 100% in this system after 24 h irradiation.