Salinosporamide A (NPI-0052) is currently produced by a marine actinomycete, Salinispora tropica, via a saline fermentation process using a non-defined, commercially available synthetic sea salt, Instant Ocean. In order to control the consistency of the production of NPI-0052 and related analogs, two chemically defined salt formulations were developed to replace Instant Ocean. A chemically defined sodium-chloride-based salt formulation with similar sodium and chloride contents as in Instant Ocean was found to support higher production of NPI-0052 and a better metabolite production profile for downstream processing than Instant Ocean. A chemically defined sodium-sulfate-based salt formulation with low chloride concentration at 17 mM was found to support a similar NPI-0052 and metabolite production profile as Instant Ocean. The sodium-sulfate-based formulation is a robust formulation for large-scale production process due to its reduced corrosiveness in fermentation as compared with the saline fermentation utilizing Instant Ocean or the sodium-chloride-based salt formulation. The production of NPI-0052 in both chemically defined salt formulations was successfully scaled-up to a 42-l fermentor, indicating that these salt formulations can be used for large-scale manufacturing process.