Ethical, environmental and health concerns around dairy products are driving a fast-growing industry for plant-based dairy alternatives, however, undesirable flavours and textures in current products are limiting their uptake into the mainstream. The proteolysis of caseins into peptides and amino acids in dairy products is a well understood process and is fundamental to developing the flavour and texture of fermented dairy products like cheese and yoghurt, yet proteolysis in plant-based alternatives is poorly understood. With this knowledge, bespoke fermentative processes could be engineered for specific food qualities in plant-based foods. This research aimed to lay the foundational groundwork for understanding how proteolysis, specifically that of cell envelope proteinases, works in plant-based dairy alternatives. A cell envelope proteinase from Lactococcus lactis, PrtP, was shown to be able to be expressed and purified in small amounts using Bacillus subtilis as an expression system. In the other component of this work, Lactic acid bacteria cultures were grown using plant proteins as the protein source, demonstrating that plant proteins are a viable substrate for these bacteria. Together, these results set the basis for future work on the detailed mechanisms of action of these proteinases in vitro and in vivo.