Total recovery of bacterioruberin from Arthrobacter via sustainable one-cycle extraction: A bench-scale guide to solvent selection and process intensification

Bacterioruberin (BR) is an uncommon C₅₀ natural carotenoid known for its exceptional antioxidant and antibacterial properties, making it highly promising for use in the food, pharmaceutical, and cosmeceutical sectors. Despite this potential, its commercial use is hindered by challenges in downstream processing. This research offers a comparative analysis of three methods to fully recover BR from Arthrobacter sp. CP30, a microorganism that produces approximately 95 % of BR and BR-derivatives. The first strategy, utilizing traditional methanol extraction, achieved a recovery rate of about 80 %, which could be improved to 100 % with optimized conditions. The second strategy employed binary solvent mixtures of alcohols and fatty acids, allowing for complete BR recovery under gentle extraction conditions. The third strategy combined green biosolvents, such as bio-based ethanol, with microwave-assisted extraction (MAE), resulting in a 100 % recovery rate and an Eco-Scale score of 89, indicating high environmental sustainability. In all methods, solvent selection was selected by COSMO-SAC modeling, which identified favorable molecular interactions between BR and the solvents tested. Overall, this work provides an efficient, sustainable, and scalable framework for BR recovery and serves as a practical guide for researchers and professionals to tailor extraction protocols according to their specific laboratory or industrial setups, to accomplish the full potential of high-value C₅₀ carotenoids.