Microbial protein: future sustainable food supply route with low environmental footprint

Abstract

Microbial biotechnology has a long history of producing feeds and foods. The key feature of today's market economy is that protein production by conventional agriculture based food supply chains is becoming a major issue in terms of global environmental pollution such as diffuse nutrient and greenhouse gas emissions, land use and water footprint. Time has come to re-assess the current potentials of producing protein-rich feed or food additives in the form of algae, yeasts, fungi and plain bacterial cellular biomass, producible with a lower environmental footprint compared with other plant or animal-based alternatives. A major driver is the need to no longer disintegrate but rather upgrade a variety of low-value organic and inorganic side streams in our current non-cyclic economy. In this context, microbial bioconversions of such valuable matters to nutritive microbial cells and cell components are a powerful asset. The worldwide market of animal protein is of the order of several hundred million tons per year, that of plant protein several billion tons of protein per year; hence, the expansion of the production of microbial protein does not pose disruptive challenges towards the process of the latter. Besides protein as nutritive compounds, also other cellular components such as lipids (single cell oil), polyhydroxybuthyrate, exopolymeric saccharides, carotenoids, ectorines, (pro)vitamins and essential amino acids can be of value for the growing domain of novel nutrition. In order for microbial protein as feed or food to become a major and sustainable alternative, addressing the challenges of creating awareness and achieving public and broader regulatory acceptance are real and need to be addressed with care and expedience.

Figure 1

Essential amino acid scoring pattern of microbial protein from bacteria (Pseudomonas/Methylophilus spp.) (), yeast (Candida spp.) (), algae (Spirulina maxima (), compared with the high‐quality animal protein from fishmeal () as well as to the FAO/WHO standard () for amino acid scoring pattern for human nutrition. Source: Harper (1981); Tacon (1987)

Figure 2

Land () and freshwater () requirements of MP compared with fishmeal and soy protein concentrate. The values are normalized to the protein content of each product. Source: Cumberlege et al. (2016)