Single-cell proteins (SCP) or microbial proteins[1] refer to edible unicellular microorganisms. The biomass or protein extract from pure or mixed cultures of algae, yeasts, fungi or bacteria may be used as an ingredient or a substitute for protein-rich foods, and is suitable for human consumption or as animal feeds. Industrial agriculture is marked by a high water footprint,[2] high land use,[3] biodiversity destruction,[3] general environmental degradation[3] and contributes to climate change by emission of a third of all greenhouse gases,[4] production of SCP does not necessarily exhibit any of these serious drawbacks.