Value from food waste

The Biorenewables Development Centre is a Research and Development centre at the University of York. We provide innovative ideas to convert plants, microbes and bio-wastes, including food wastes, into high-value products. The term ‘valorisation’ refers to the process of converting waste materials into more useful products. These useful products could include food, but also chemicals, materials and fuels. These aren’t necessarily high value products, but it can also mean that by doing so, companies mitigate the costs of disposal. An example of this is Toast Ale, who convert surplus fresh bread waste into beer. One project we’ve worked on is with Croda - a fine Chemicals company producing ingredients for a number of different product areas.

Croda has a microbial strain which produces significant quantities of novel antifungal compounds that are used in the personal care market, for example in anti-dandruff shampoos. In this project we investigated whether it was possible to replace the standard pure sugar-based media used to grow the organism, with a carbohydrate-rich food waste feedstock. We were able to show that a number of food waste streams were able to support the growth of the microbe and produce the compounds of interest. We’ve also looked at uses for bread waste in a project with GSK, Veolia and IBioIC. An estimated 11,860 tonnes of unavoidable dough by-product and 23,180 tonnes of unavoidable baked product is potentially available in the UK.

In this project bread waste was processed to reduce particle size, enzymatically hydrolysed to convert the starch to glucose, cleaned up to remove residual solids (fibre and protein fractions, salts and other impurities) and finally concentrated to produce a glucose syrup that was used in fermentation to produce pharmaceutical actives. Another project we’ve undertaken looked at increasing the value of ice-cream waste with Unilever. It is estimated that up to 10% off all ice cream ends up as waste in various forms. Currently this ice cream waste is sent for animal feed but we were engaged to investigate whether this material could be used to produce higher value products.

Through fermentation screening trials the BDC assessed the potential of this sugar and oil-rich feedstock to produce low-volume, high-value chemicals using a range of industrially relevant microbial strains. These trials showed that ice-cream waste had the potential to be used to create platform chemicals – succinic acid and lactic acid (a precursor for bioplastics), for Biofuels – ethanol, butanol, as well as Industrially relevant enzymes – fat-degrading lipases used in biological washing powders and detergents. This last use was of particular interest to Unilever as they currently use lipases in a number of their home care products. For every waste stream, there is a potential business opportunity.