Detection of antibacterial activity in an enzymatic hydrolysate fraction obtained from processing of Atlantic rock crab (Cancer irroratus) by-products

• Fractions isolated from enzymatic hydrolysis of Atlantic rock crab by-products.
• Inhibitory activity against several Gram-negative bacilli strains demonstrated.
• Inhibitory activity against some Gram-positive strains detected.
• Purification of an anionic fraction by SP-Sepharose™ Fast Flow cation exchanger.
• Molecules ranging from 200 to 750 Da in the antibacterial peptide fraction isolated.

Peptide fractions generated via proteolytic processing of Atlantic rock crab by-products were tested for antibacterial activities against bacterial strains of interest in food and health. Of all fractions obtained the specific nano-filtered retentate exhibited an antibacterial activity. The peptide fraction demonstrated inhibitory activity against several Gram-negative bacilli and against some Gram-positive bacteria. The principal bioactive peptide fraction was of low molecular weight and was comprised mainly of proteins, 74%, and minerals, 16%. The amino acid content revealed that lysine, leucine, arginine, aspartic acid and glutamic acid residues were represented in the highest composition. The optimal inhibitory activity was observed at alkaline pH 9. The first step of purification, performed on a chromatography resin, led to the isolation of an anionic antibacterial peptidic fraction. Following gel permeation chromatography analysis, the active peptide fraction appears to be a complex of molecules ranging from 200 Da to 750 Da. Results indicating the production of antibacterial molecules from enzymatic hydrolysis of Atlantic rock crab by-products should be viewed in high-value bioproducts in several areas such as food and health sectors.