Single-cell protein: overcoming technological and biological challenges towards improved industrialization

The commercialization of single-cell protein (SCP) obtained from microbial fermentation in large-scale bioreactors emerged almost 50 years ago, with Pruteen marketed as animal feed in the 1970s and Quorn®, released for human nutrition in 1985. SCP holds great promises to feed the meanwhile doubled world population in a sustainable way, but its application is still limited by price and availability on scale. There is a need to optimize the underlying manufacturing processes with enhanced affordability and productivity. From the industrial perspective, it is crucial to identify key process components and prioritize innovations that best promote cost efficiency and large-scale production. Here, we present the state-of-art in SCP manufacturing and provide a comprehensive insight into recent techno-economic analyses and life-cycle assessments of different production scenarios. Thereby, we identified the most influential technical hotspots and challenges for each of the main production scenarios and evaluated the technological opportunities to overcome them. [Display omitted] ●Ionic liquids and immobilized cellulase enzymes can reduce cost for heterotrophic SCPs.●Membrane bioreactor improves gas-liquid mass transfer for autotrophic SCPs.●Co-cultivation method has demonstrated increased protein productivity and quality.●Flocculation technique offers potential solution for small sized microorganisms.