This work reveals a novel application of the catholyte produced during the operation of a tubular terracotta MFC. These results show great promise since they demonstrate that algae can de used as a natural carbon source in terracotta-based MFCs when treated with the catholyte that has been synthesised in-situ. Further work is required to better understand the lysing mechanisms as well as the process of nutrient extraction, to optimise the catholyte and algal biomass ratio and improve the operating conditions from batch to continuous flow.