Integrated extractive disruption of Gordonia terrae cells with direct recovery of carotenoids using alcohol/salt aqueous biphasic system

Microbial carotenoids are gaining attention because of the unsustainable supplies of natural plant sources of carotenoids. The downstream processes of the microbial carotenoids are often limited by high cost of production and multi-steps unit operation. Aqueous biphasic system (ABS) comprised of alcohol and salt is suggested as a potential approach to overcome these limitations for recovery of Gordonia terrae carotenoids in this study. Aliphatic alcohols inclusive of 1-propanol and 2-propanol and sulphate, citrate and phosphate salts were used to develop the alcohol/salt ABS to recover the microbial carotenoids. The optimum ABS for the integration of G. terrae cells disruption and simultaneous recovery of carotenoids was developed by evaluating the effects of concentration of phase-forming components, pH, amount of crude loads, concentration of additives, sonication time on the recovery yield of carotenoids. Repetitive batch-extraction of carotenoids using the optimum alcohol/salt ABS was performed to investigate the feasibility of ABS as the sustainable and consistent method for recovery of microbial carotenoids. High recovery yield of carotenoids (90.86 +/- 2.97%) was obtained with 20% (w/w) 1-propanol and 20% (w/w) trisodium citrate salt of pH 9. A total of 10% (w/w) of G. terrae cells was loaded into the optimized system with the addition of 4% (w/w) of NaCl. The optimized system is suggested to perform without sonication because degradation of the carotenoids was observed with sonication applied. A total of 4 batches of ABS extraction were conducted until all carotenoids were completely extracted from the G. terrae cells. The high-water content and cost-effective one-step ABS allows the process integration of extraction and separation of carotenoids from G. terrae fermentation.