description
- As prosperity rises, demand for meat increases as it is a rich source of protein. This in turn places demand on water resources, changes land use (in a manner highly dependent upon how the animal is fed) and leads to an increase in anthropogenic GHG emissions. This has been determined to be unsustainable by a number of international bodies, with some estimates predicting a 70% rise from current levels of 11% of total GHG emissions by 2050. However, demand for protein can also be met by crop-based sources (e.g. soy and pulses) and by mycoprotein, produced by fermentation of crop-derived glucose into biomass, which is harvested and processed into high quality protein. Mycoprotein remains a relatively under-exploited resource worldwide but offers great promise for year-round production of high quality protein, a vital requirement for future food security and human nutrition. The most significant challenge to production is the reliance on a single carbon source, a wheat-derived glucose, which requires special processing before it is suitable for use. Our recent work has revealed that while the fungus used to produce mycoprotein is grown on this glucose substrate, production of a number of essential vitamins is inhibited. Our recent work has revealed that expression of vitamins in some other carbon sources, for example beet derived sucrose syrup is observed. In some, but not all cases, this is coupled to an increase in other deleterious secondary metabolites. This leads to the question, how is the fungus regulating secondary metabolism in relation to carbon source? To expand both the nutritional value of mycoprotein and the range of carbon sources that can be utilised (enabling production to move to other regions of the world) we will use the latest DNA sequencing techniques to reveal the structure of the genome of Fusarium venenatum and study the regions of the genome that contain secondary metabolite genes. From work carried out in other related fungi it is known that control of secondary metabolism (SM) is regulated by the position of SM cluster in the genome, and by specific regulatory factors. Utilising the latest sequencing techniques will allow us to positionally resolve SM location and determine the underlying mechanisms regulating responses to different carbon sources. Through a series of controlled batch and continuous culture experiments we will develop techniques to selectively induce vitamin biosynthesis across a range of carbon sources, without inducing the expression of deleterious SM genes, providing both an understanding of the control of SM and an enhanced product for future product development. Building on our existing work we will expand the toolbox of molecular techniques in order to edit the genome of F. venenatum to remove deleterious secondary metabolite gene clusters and their regulatory factors which are induced in response to different carbon sources. As a result of this work, mycoprotein will be able to be produced using a larger range of carbon sources drawing upon a wider range of UK agricultural sources (maize, barley, rice) and even shift to sucrose-based production of mycoprotein (a carbon source that has currently been completely inaccessible), utilising UK sources of sucrose such as sugar beet. Furthermore, the ability to enhance the complement of micronutrients in mycoprotein will broaden its utility as an important component of global diets and offers a more sustainable and flexible alternative to meat.