Studying Production of Protein Hydrolysates from Fish By-Products using Bacillus sp.

Abstract

Fish by-products contain a large amount of nutritious proteins. However, nowadays in the fish processing industry, they are often seen as a source of waste to be disposed of. In this study, Bacillus sp. was used to convert fish by-products into protein hydrolysates intended for serving as a liquid organic fertilizer for crops. The fermentation medium was mixed to include one gram of ground fish by-products and four grams of cane molasses per three milliliters of water; the bacteria inoculum was approximately 1.1 × 109 CFU/ml at pH 7.0; the bacterial culture was shaken at 130 rpm at room temperature. After 36 hours of fermentation, analysis of the final hydrolysate showed that: (i) the degree of protein hydrolysis was 71.6%; (ii) NPK was about 0.38:0.15:0.06; (iii) pH was 6.41;(iv) total amino acids was 0.52 g/100 g solution; (v) phytotoxicity was low and (vi) at a 600-fold dilution, the hydrolysates showed an improvement in leaf width and length on 40-day-old mustard greens [Brassica juncea (L.) Czern].