Amine oxidase-based flow biosensor for the assessment of fish freshness

Amine oxidases (EC 1.4.3.6) from grass pea (Lathyrus sativus) seedlings and fungus Aspergillus niger were immobilized to construct flow enzyme reactors for amine assay with spectrophotometric detection of enzymatically produced hydrogen peroxide by a peroxidase/guaiacol system. While immobilized amine oxidase from A. niger showed poor storage stability, the L. sativus enzyme-based system was found useful for assay of putrefactive amines (putrescine and histamine) as markers of fish meat decomposition. The optimized biosensor with average lifetime 20 days showed a linear response to the amount of histamine in the range 7.0–90 nmol with the assay limit of 4.4 nmol and putrescine in the range 0.9–70 nmol with the assay limit of 0.5 nmol.