Ionic Liquids toward Enhanced Carotenoid Extraction from Bacterial Biomass

Area of Science:

• Biotechnology
• Natural Product Extraction
• Microbial Pigments

Background:

• Carotenoids are valuable compounds with intense coloration and antioxidant properties, sourced from diverse organisms.
• Gordonia alkanivorans strain 1B is a potent bacterial pigment producer, but its solvent resistance complicates traditional extraction.
• Ionic liquids (ILs) show promise for carotenoid extraction from plants and microalgae, yet their application in bacteria, particularly Gordonia, is underexplored.

Purpose of the Study:

• To investigate the efficacy of ILs for extracting carotenoids from bacterial biomass.
• To develop an optimized, efficient extraction method with reduced pre-processing steps.
• To enhance carotenoid recovery from Gordonia alkanivorans strain 1B.

Main Methods:

• Screening of nineteen ILs and co-solvents for carotenoid extraction from G. alkanivorans strain 1B biomass.
• Optimization of IL#18 (tributyl(ethyl)phosphonium diethyl phosphate) and ethyl acetate (EAc) concentrations using experimental designs.
• Comparison of the novel IL-based method with conventional Dimethyl sulfoxide (DMSO) extraction.

Main Results:

• Tributyl(ethyl)phosphonium diethyl phosphate (IL#18) with ethyl acetate (EAc) demonstrated superior carotenoid extraction.
• Optimal conditions identified: 50 µL IL#18, 1125 µL EAc, and 400 µL biomass suspension (36 g/L).
• The IL-based method increased carotenoid yield by 264% compared to DMSO, eliminating biomass drying and reducing extraction temperature.

Conclusions:

• Ionic liquids, specifically IL#18/EAc, offer a highly effective strategy for bacterial carotenoid extraction.
• This method significantly improves process efficiency, reduces energy consumption, and lowers costs and emissions.
• The findings support the potential of ILs for industrial-scale recovery of carotenoids from microbial sources.