Bioconversion of seaweeds for aquaculture feeds and biotechnology

The world’s increasing demand for food generates a powerful economic imperative for innovation in food production technology. Our novel system was discovered through a Marsden project and developed through a Smart Ideas grant, and has the potential to create several new products for the global food supply chain.
Our research has revealed that (a) symbiotic microbes in the hindgut of wild NZ seaweed-eating fishes rapidly and completely convert seaweed and atmospheric nitrogen into compounds of nutritional value to fish, (b) these hindgut microbes provide an important source of dietary protein to the fish, and (c) these novel organisms can be grown in culture. Culturing these microbial communities to bioconvert abundant and sustainable seaweeds addresses four global problems: (a) the economic and environmental costs of feeding capture fish to cultured fish, (b) the unsuitability of many terrestrial protein sources for aquaculture feeds due to the lack of critical nutrients and the presence of compounds inhibitory to digestion, (c) current roadblocks to using abundant seaweed biomass to produce animal feeds (especially arsenic accumulation), and (d) the growing demand for sustainable agricultural fertiliser. This is a completely novel idea on an international level, as we have only just discovered and begun to understand the microbial and physiological processes that underpin the natural fish/microbe symbiosis.
Our proposed work elaborates three fundamental science strands: microbial community assembly, arsenic metabolism and bacterial growth factors. We will use these to unlock a number of economic opportunities for NZ by maximising the production of desired fermentation end products for animal feeds and fertiliser. A spill-over benefit is the potential use of our fermentate to grow black soldier fly larvae, which have growing global importance as animal feed components.