Peptones from Atlantic Cod Stomach as Nitrogen Sources in Growth Media to Marine Bacteria

Peptones were obtained from cod stomachs as a by-product during enzyme production. Minced cod stomachs were autolyzed after acidification with either formic or phosphoric acid, and low molecular weight (< 10 kDa) peptones were recovered. When formic acid was used, an acid peptone was obtained, whereas phosphoric acid was removed from the peptone after calcium precipitation. The peptones were compared with Proteose Peptone (Difco, Detroit, MI, USA) as nitrogen sources in growth media for three marine bacteria. Two fish pathogens—Vibrio anguillarum and Aeromonas salmonicida—grew equally well or better on the cod stomach peptones, whereas a probiotic lactic acid bacteria (Carnobacterium divergens), isolated from salmon intestines, grew much better on the cod stomach peptones than on Proteose Peptone.