Optimized production of bacterioruberin from "Haloferax marinum" using one-factor-at-a-time and central composite design approaches

Haloarchaea represents a unique group of microorganisms that have adapted to thrive in high-salt environments. These microbes produce distinctive biomolecules, some of which exhibit extraordinary properties. One such biomolecule is bacterioruberin, a prominent red-pigmented C50 carotenoid commonly found in halophilic archaea, renowned for its antioxidant properties and potential as a functional resource. This study aimed to enhance the culture conditions for optimal production of C50 carotenoids, primarily bacterioruberin, using "Haloferax marinum" MBLA0078. The optimization process involved a combination of one-factor-at-a-time (OFAT) and statistical methodology. Under OFAT-optimized conditions, fed-batch fermentation, and response surface methodology (RSM) optimization, carotenoid production reached 0.954 mg/L, 2.80 mg/L, and 2.16 mg/L, respectively, in a 7-L laboratory-scale fermenter. Notably, RSM-optimized conditions led to a 12-fold increase in productivity (0.72 mg/L/day) compared to the basal DBCM2 medium (0.06 mg/L/day). These findings suggest that strain MBLA0078 holds significant promise for commercial-scale production of bacterioruberin.