Dalhousie University

Purpose

The project will address the problem of waste disposal in aquaculture by using cultures of marine protists to remediate and up-cycle nutrient-rich wastes. The remediation will be coupled to production of aquaculture feeds, reducing fishing pressure on wild stocks of fish. The feedstocks will be waste products of fish processing (heads, viscera etc.), converted to highnutrient liquid forms through hydrothermal liquefaction or enzymic hydrolysis. These will generate protist biomass for use in feeds. The protists will include algae commonly used in aquaculture because of their growth responses and their biochemical composition. Strains capable of growing mixotrophically will be prioritized (mixotrophy is a nutritional mode in which organisms simultaneously gain energy through photosynthesis and heterotrophy, the digestion of organic compounds). The protists will also include thraustochytrids, heterotrophic unicells previously classified as fungi. Use of both algae and thraustochytrids will increase the efficiency of remediation compared to use of either alone.