PhD research into value from agricultural wastes

The human population is projected to reach 9.8 billion by 2050. Consequently, food security presents an ever-increasing global challenge where supply must match rising demand. As a result, there is a growing need for sustainable food production, particularly of meat, which since the 1940s has seen global consumption rise by around fivefold. Global fish consumption has also increased, with aquaculture now the world’s fastest growing food production system. Meat and aquaculture production rely on a sufficient supply of protein-rich feed which is mainly provided by soybean and fish meals; demand for which will continue to increase, so much so that a deficit of at least 60 million tonnes is projected by 2050. Soybean and fish meal production is also unsustainable and increasingly expensive.

Therefore, alternative, sustainable and cost-effective feed sources should be pursued, and Black Soldier Fly larvae are particularly promising. They are ideal to farm as protein-rich livestock feed, with protein content comparable to soybean and fish meals and essential amino acid profiles that match those required by livestock like pigs, chickens and fish. But, Black Soldier Fly larvae themselves require a sustainable food source to be farmed as feed at industrial scale. My PhD research, within the Centre for Novel Agricultural Products at the University of York and alongside industry collaborators at Fera Science, provides a potential solution to this problem. How do we sustainably feed Black Soldier Fly larvae so they can be farmed as a novel livestock feed?

My research focuses on using agricultural crop residues (wheat straw for example) to feed Black Soldier Fly larvae. These crop residues represent an inexpensive, abundant, and sustainable feedstock. The UK produces 12 million tonnes of wheat straw alone annually, of which around 4 million tonnes are surplus and currently not collected or valorised. However, crop residues are composed largely of a structure called lignocellulose. Lignocellulose is a composite material composed primarily of the sugar-rich secondary plant cell walls; but the nutritional potential is locked behind a recalcitrant matrix of aromatic polymers (known as lignin) that requires specialised enzymes to digest it. Because of this, Black Soldier Fly larvae cannot grow on crop residues like wheat straw, as I’ve shown in my PhD.

My research is developing a platform process technology to pre-treat crop residues, releasing these sugars and nutrients, to produce a palatable feed for Black Soldier Fly larvae rearing. With this technology, the Black Soldier Fly sector may be able to produce protein at a scale not yet possible with current larvae feeds, addressing the food security challenge as well as waste management.