An innovative simplified one-pot process for Astaxanthin purification from Paracoccus carotinifaciens

Astaxanthin (ASX) is a carotenoid with several applications in the food and pharmaceutical fields which is recognised as having a higher physiological and commercial value when it is biologically rather than chemically sourced. This work experimentally investigates the bio-fractionation of biomass of the Paracoccus carotinifaciens bacterium by extraction with the switchable hydrophilicity solvent N,N-dimethyl cyclohexylamine (DMCHA) to obtain ASX and related carotenoids in separate form. This is done by means of a sequential process carried out in a single apparatus. DMCHA gave an extraction yield in terms of equivalent ASX extracted per unit mass of processed dry microbial biomass (62.5 %) higher than acetone (48 %) and ethanol (14 %). After the DMCHA was washed from the extract with carbonated water, 88.2 % of the extracted ASX was recovered. The possibility of extracting carotenoids with recycled solvent with a minor (-7.7%) efficiency drop was also demonstrated, as was the lower energy footprint of DMCHA-based than competing volatile solvent-based extraction processes.