Efficient extraction of canthaxanthin from Escherichia coli by a 2-step process with organic solvents

Canthaxanthin has a substantial commercial market in aquaculture, poultry production, and cosmetic and nutraceutical industries. Commercial production is dominated by chemical synthesis; however, changing consumer demands fuel research into the development of biotechnology processes. Highly productive microbial systems to produce carotenoids can be limited by the efficiency of extraction methods. Extraction with hexane, acetone, methanol, 2-propanol, ethanol, 1-butanol, tetrahydrofuran and ethyl acetate was carried out with each solvent separately, and subsequently the most efficient solvents were tested in combination, both as mixtures and sequentially. Sequential application of methanol followed by acetone proved most efficient. Extraction efficiency remained stable over a solvent to biomass range of 100:1 to 55:1, but declined significantly at a ratio of 25:1. Application of this method to a canthaxanthin-producing Escherichia coli production system enabled efficient canthaxanthin extraction of up to 8.5 mg g−1 dry biomass.