A major problem with the production of high value products from fisheries waste arises from the unavoidable variability of waste material from capture fisheries. To minimise the impact of this variability on the reproducibility of product formation, we have used three strategies.
1. endogenous proteases and peptidases have been heat-inactivated prior to addition of controlled amounts of exogenous enzymes. This step decreases product variability due to the presence of endogenous enzyme (variable in nature and quantity).
2. controlled hydrolysis has been carried out using mixtures of commercial proteases and peptidases to increase waste protein digestibility and maximise the formation of low molecular mass products.
3. where larger molecular mass products are required, control over the feedstock waste is needed. This can be achieved by the use of waste from farmed fish rather than capture fisheries.
Using capture fisheries waste, the potential applications of hydrolysates will be those requiring only small peptides or free amino-acids such as microbial and/or cell culture media, flavour enhancers (organoleptics) feeding stimulants (for aquaculture species), dietary supplements (to enhance foods with amino acid deficiencies).
Using aquaculture species wastes, the potential applications will be those requiring larger peptides with biological activities such as immuno-stimulants, enzyme inhibitors, peptides hormones.
The result is a process using enzyme biotechnology to upgrade low value fisheries wastes to high value products. The process can be applied to products of interest to aquaculture, food science, microbiology and cell biology.
Given concerns about the possible consequences of using cell culture media based on animal products (e.g. calf serum). culture media based on fisheries waste may be seen to have considerable potential. In addition, using natural immuno-stimulants to replace antibiotics and other medicines in aquaculture may be more attractive to farmers and consumers as well as decreasing the levels of undesirable residues in marketed aquaculture products. The potential use of products in aquaculture nutrition as replacements for expensive fish meal may allow the development of lower-cost and sustainable diets based largely on plant proteins. The use of enzymes to reproduce hydrolysates from fish wastes has a long history. little work has been carried out using mixed enzyme protarations to enhance waste digestibility and improve products reproducibility. Most immuno-stimulants are base on microbial polysaccharides or chitinous wastes from shellfish. There is relatively little work published on peptide immunostimulants. Our results are at least comparable with the state of the art in the field.
The process relies only on available technologies in the biotechnology/food industries. It does not require the development of new technologies for exploitation.