Valorization of marine by-products using green technology

In this work, two cases of marine by-product valorization using green technologies were highlighted, i.e., utilization of high-pressure carbon dioxide (HPCD) for demineralization of goldstripe sardinella (Sardinella gibbosa) scales and the use of non-specific enzymes for chitosan hydrolysis. After demineralization, type I collagen can be recovered from sardine scales. This work used HPCD process (of up to 10 bar or 1 MPa) to remove minerals from scales instead of the traditional strong acid method. Results from initial phase of the work showed that the process efficiency was significantly affected by pressure applied and treatment time (p < 0.05). And the demineralization efficiency reached was significantly lower than that achieved by treatment with hydrochloric acid (p < 0.05). In the second study, the chitosanolytic activity of four non-specific enzymes were assessed for chitosan hydrolysis. The results indicated that acid protease and cellulase could be a potential choice to produce chitooligosaccharides (COS) from shrimp shell.