This project benchmarks five DIA-based LC–MS platforms for their ability to quantify proteins in E. coli and Halomonas bluephagenesis under biomanufacturing‑relevant conditions. Using simple peptide ratio mixtures and an exemplar carbon source comparison, it shows how instruments across a range of costs can still deliver actionable coverage of core metabolic pathways. The work is aimed at positioning quantitative proteomics as a practical tool for chassis selection, process development, and troubleshooting in industrial biomanufacturing.