Microbial and enzymatic production of 4,4′-dihydroxybiphenyl via phenol coupling

Phenol was coupled to produce 4,4′-dihydroxybiphenyl in an in vitro system containing phosphate buffer, H₂O₂, phenol, and horseradish peroxidase (EC 1.11.1.7). Other products were also detected. Preliminary experiments with an in vivo fungal fermentation system containing phenol as a substrate also resulted in the production of 4,4′-dihydroxybiphenyl. The results suggest that the biphenols are themselves substrates for the enzymes.