Aquaculture Canada and WAS North America 2022

August 15 - 18, 2022

St Johns, Newfoundland, Canada


 David T. Hopkins*, Fabrice Berrué, Zied Khiari, & Kelly A. Hawboldt

            Department of Process Engineering, Faculty of Engineering Memorial University of Newfoundland 230 Elizabeth Avenue, A1B 3X5 St. John’s, NL


By-products from fish processing plants can vary from 30-70

weight percent of landed material depending on the species and  the product-dependent  degree of processing. These by-products, taking the form of fish frames, viscera, and shell material, result in an environmental burden in terms of treatment and disposal, generating both high organic load liquid wastes and emission of greenhouse gases in degradation . However, these streams contain commodities such as industrial chemicals, as well as nutritional and medicinal compounds. Extraction of these compounds would not only decrease the environmental burden from processing but  also provide a revenue stream. Thermochemical, biochemical, and mechanical processes can be used in product extraction. However enzymatic processes offer the advantage of preserving the integrity of the extract and do not require intensive processing conditions , which could include  high temperatures, toxic chemicals etc.  Proteolytic enzyme hydrolysis, which uses protein-digesting enzymes to catalyze the decomposition of substrate proteins into smaller, more soluble peptides , can be used as a treatment to separate proteins from lipids, carbohydrates, and minerals, or as a post treatment after lipids and/or bioactive

 chemicals  are extracted. The  end goal is the same, a protein rich hydrolysate, however the process route impacts the chemical matrix of the feedstock.

These matrix effects are poorly understood, despite their vast importance in reaction kinetics and process scale-up and require further review and research.

In this presentation, the impact of feedstock properties on the enzyme hydrolysis reaction are discussed , along with observations  and potential correlations between feedstock properties, effects of substrate pre-treatments, and the resultant kinetics and maximum degree of hydrolysis achieved in the reaction .  Limitations of current research due to the use of destructive techniques in pre-treatment are then discussed, and non-destructive methodologies for study of matrix effects in the enzyme hydrolysis reaction based on results from past literature are introduced .  Lastly,

conclusions are made, providing an outlook for research in this field, including recommendations for future analysis.