Comparing three emerging industrial cell factories: Pseudomonas putida KT2440, Halomonas bluephagenesis TD01, and Zymomonas mobilis ZM4.

Nonmodel microbes with unique advantages are emerging as industrial platforms, driven by advances in genetic engineering and omics technologies. Notable examples include the versatile soil bacterium Pseudomonas putida KT2440, the halophilic Halomonas bluephagenesis TD01, and the ethanologenic Zymomonas mobilis ZM4. While all three primarily use the Entner-Doudoroff pathway for glucose metabolism, they differ in various metabolic pathways and product synthesis. This review summarizes and compares their central carbon metabolism, advancements in genome engineering tools, and progress in scaling industrial applications from lab scale, to pilot scale, to full-scale commercial production. Understanding their similarities and differences informs future research on optimizing industrial applications and may guide the development of new microbial hosts.