The appropriate course of action to stop the spread of COVID-19 involves immunizations due to the rise in COVID-19 cases. Pichia pastoris serves as the protein expression system for RBD, a spike protein produced by the SARS-CoV-2 virus. RBD is utilized as an antigen for vaccine candidates to tackle COVID-19 which is suitable for low to middle-income countries. The Tangential Flow Filtration…