Use of flavin containing monooxygenases for conversion of trimethylamine in salmon protein hydrolysates

Enzyme-based conversion of marine biomass to high quality peptide ingredients leaves a distinct smell of “fish” caused by the presence of trimethylamine, which is limiting their economic potential. We suggest an enzymatic solution for converting trimethylamine to the odorless trimethylamine N-oxide as a novel strategy to improve the smell quality of marine protein hydrolysates. Following a systematic investigation of 45 putative bacterial trimethylamine monooxygenases from several phyla, we expand the repertoire of known active trimethylamine monooxygenases. As a proof-of-concept, we demonstrate that three of these enzymes oxidized trimethylamine in an industry-relevant salmon protein hydrolysate. Our results add new oxidoreductases to the industrial biocatalytic toolbox, and provide a new point of departure for enzyme process developments in marine biorefineries.