Published May 24, 2023 | Version v1
Journal article Open

Increased Thermostability of an Engineered Flavin-Containing Monooxygenase to Remediate Trimethylamine in Fish Protein Hydrolysates

  • 1. NORCE Climate & Environment - NORCE Norwegian Research Centre, Bergen, Norway
  • 2. Instituto de Quimica Fisica Rocasolano (IQFR), CSIC, Madrid, Spain
  • 3. Instituto de Catalisis y Petroleoquimica (ICP), CSIC, Madrid, Spain


Protein hydrolysates made from marine by-products are very nutritious but frequently contain trimethylamine (TMA), which has an unattractive fish-like smell. Bacterial trimethylamine monooxygenases can oxidize TMA into the odorless trimethylamine N-oxide (TMAO) and have been shown to reduce TMA levels in a salmon protein hydrolysate. To make the flavin-containing monooxygenase (FMO) Methylophaga aminisulfidivorans trimethylamine monooxygenase (mFMO) more suitable for industrial application, we engineered it using the Protein Repair One-Stop Shop (PROSS) algorithm. All seven mutant variants, containing 8 to 28 mutations, displayed increases in melting temperature of between 4.7°C and 9.0°C. The crystal structure of the most thermostable variant,
mFMO_20, revealed the presence of four new stabilizing interhelical salt bridges, each involving a mutated residue. Finally, mFMO_20 significantly outperformed native mFMO in its ability to reduce TMA levels in a salmon protein hydrolysate at industrially relevant temperatures.


Increased Thermostability of an Engineered Flavin-ContainingMonooxygenase to Remediate Trimethylamine in Fish ProteinHydrolysates.pdf

Additional details


OXIPRO – Transition towards environment-friendly consumer products by co-creation of an oxidoreductase foundry 101000607
European Commission
FuturEnzyme – Technologies of the Future for Low-Cost Enzymes for Environment-Friendly Products 101000327
European Commission