Waste from aquaculture and fishing is a major issue in coastal areas. The global fishing industry is estimated to produce 179 million tonnes each year, of which 156 million tonnes are used to produce food for human consumption. The remaining aquaculture is converted into low-value products like animal feed and fertilizers.
With a harvest of more than around 5 million pounds, snow crab constitutes one of the largest harvested species in Nova Scotia. Crab legs and shoulders are the only pieces of the crab that are commercially valued, leaving around one-third of the crab untouched and going into waste composting or landfilling facilities, contributing to methane and CO2 emissions. This waste, however, contains high-value organic and inorganic materials which can be reprocessed and used in a variety of higher-end products.
The thermochemical conversation is a technique used to degrade biomasses thermally in a deoxygenated environment. This process yields two main products, known as biochar and biooil. The biochar generated from the pyrolysis of crab body is rich in Calcium which can be used in various applications including catalysis.
As we are moving away from fossil fuels, the demand for biodiesel as an alternative energy source is increasing. Consequently, the production of biodiesel from waste triglycerides such as vegetable, fish, and animal oils has also increased, resulting in the production of substantial quantities of crude glycerol of economic value as well as fuel. We have demonstrated that the calcium-based crab biochar can be implemented as a catalyst for transesterification of vegetable and fish oil generating a renewable biodiesel from two under-utilized waste streams.