Bacterium

Technical Data

Type of microorganism	Bacterium
Target proteins	Whey proteins, caseins, egg proteins, sweet proteins, meat proteins, enzymes. See organism table for specific cases.
Wild-type or GMO	All described examples are GMO. See organism table for specific cases.
Production mode (intracellular/extracellular)	Extracellular in Gram-positive bacteria, Intracellular in Gram-negative bacteria (E. coli), due to secretion to periplasmic space (Spohner et al., 2015)
C & N source	Mainly glucose and glycerol as C-source, amino-acids are prefeered as N-sources, often supplied in the from of yeast extract (Overton, 2014).See organism table for specific cases.
Regulatory status in Europe	The production of food related proteins in bacteria is not allowed. Some cases are issued as safe for consumption by EFSA, but are not allowed yet. See organism table for specific cases.
Regulatory status in other parts of the world	Several products have FDA GRAS apporval or self-affirmed GRAS in the US. No products allowed in Canada. See organism table for specific cases.
Companies	Clasado Evonik (for cosmetics) AB enzymes Advanced Enzymes Technologies Geltor (for cosmetics) Mycotechnology
Average yield	1-22 g/L (Eastham & Leman, 2024)
General temperature range	15-45°C (Zhuang et al., 2024)
General pH range	pH 6-8 (Zhuang et al., 2024)
Growth rate (µ)	0.35-1.39/hour (Bratosin et al., 2021)
Ease of genetic modification	Generally very easy genetic manipulation, especially for model organisms (which are also the most used bacteria in precision fermentation) (P. Yang et al., 2024).
Feedstock suitability	Can grow on a variety of agro-industrial waste streams, but to a lesser extent than yeasts and fungi (Dey et al., 2025)
Downstream purification processing complexity (isloation, lysis, purification)	For secreted proteins: simple centrifugation followed by purification of protein in the supernatant (mostly done by chromatography, complexity depends on the protein) (Tripathi & Shrivastava, 2019) For intracellular & periplasmic proteins: cell lysis step needed. Bacteria are generally ease to lyse, but Gram-positive bacteria are harder to lyse than Gram-negrative bacteria due to their thicker cell wall (T. A. Gomes et al., 2020)
Advantages	Fast growth, cheaper (lower media cost and faster process) (Overton, 2014)
Challenges (Key limitations, risk factors)	Non-eukaryotic PTMs, which can lead to misfolding and yield loss. Low yields. Endotoxin production by Gram-negative bacteria (Eastham & Leman, 2024)
Publications/references	Eastham, J. L., & Leman, A. R. (2024). Precision fermentation for food proteins: ingredient innovations, bioprocess considerations, and outlook — a mini-review. Current Opinion in Food Science, 58, 101194. https://doi.org/10.1016/j.cofs.2024.101194 Zhuang, Z., Wan, G., Lu, X., Xie, L., Yu, T., & Tang, H. (2024). Metabolic engineering for single-cell protein production from renewable feedstocks and its applications. Advanced Biotechnology, 2(4). https://doi.org/10.1007/s44307-024-00042-8 Bratosin, B. C., Darjan, S., & Vodnar, D. C. (2021). Single Cell Protein: A Potential Substitute in Human and Animal Nutrition. Sustainability, 13(16), 9284. https://doi.org/10.3390/su13169284 Yang, P., Condrich, A., Lu, L., Scranton, S., Hebner, C., Sheykhhasan, M., & Ali, M. A. (2024). Genetic Engineering in Bacteria, Fungi, and Oomycetes, Taking Advantage of CRISPR. DNA, 4(4), 427–454. https://doi.org/10.3390/dna4040030 Spohner, S. C., Müller, H., Quitmann, H., & Czermak, P. (2015). Expression of enzymes for the usage in food and feed industry with Pichia pastoris. Journal of Biotechnology, 202, 118–134. https://doi.org/10.1016/j.jbiotec.2015.01.027 Overton, T. W. (2014). Recombinant protein production in bacterial hosts. Drug Discovery Today, 19(5), 590–601. https://doi.org/10.1016/j.drudis.2013.11.008 Tripathi, N. K., & Shrivastava, A. (2019). Recent Developments in Bioprocessing of Recombinant Proteins: Expression Hosts and Process Development. Frontiers in Bioengineering and Biotechnology, 7. https://doi.org/10.3389/fbioe.2019.00420 Gomes, T. A., Zanette, C. M., & Spier, M. R. (2020). An overview of cell disruption methods for intracellular biomolecules recovery. Preparative Biochemistry & Biotechnology, 50(7), 635–654. https://doi.org/10.1080/10826068.2020.1728696 Dey, S., Talukdar, A., & Bhattacharya, S. (2025). Microbial degradation and valorization of food wastes: waste to wealth approaches towards sustainability. Discover Chemistry., 2(1). https://doi.org/10.1007/s44371-025-00217-9

Escherichia coli

Bacillus subtilis

Lactococcus lactis

Corynebacterium glutamicum

Streptomyces sp.

Lactobacillus sp.