Partition efficiency of cytochrome c with alcohol/salt aqueous biphasic flotation system

Enhanced recovery of astaxanthin from recombinant Kluyveromyces marxianus with ultrasonication-assisted alcohol/salt aqueous biphasic system

Microbial astaxanthin with strong antioxidant activity is greatly demanded for diverse applications. Extractive disruption in aqueous biphasic system (ABS) integrates the cells disruption and biomolecules recovery processes in one-step operation, allowing the direct recovery of intracellular biomolecules with biphasic system upon released from cells. In this study, astaxanthin was recovered from recombinant Kluyveromyces marxianus yeast cells via extractive disruption using alcohol/salt ABS. Recombinant K. marxianus yeast is engineered to produce high concentration of free form astaxanthin. Highest partition coefficient (K = 90.02 ± 2.25) and yield (Y = 96.80% ± 0.05) of astaxanthin were obtained with ABS composed of 20% (w/w) 1-propanol and 20% (w/w) sodium citrate of pH 5, 0.5% (w/w) yeast cells loading and additional of 1% (w/w) 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim)BF₄ to improve the migration of astaxanthin to alcohol-rich top phase. The incorporation of 2.5 h of ultrasonication to the biphasic system further enhanced the astaxanthin recovery in ABS. The direct recovery of astaxanthin from recombinant K. marxianus cells was demonstrated with the ultrasonication-assisted alcohol/salt ABS which integrates the extraction and concentration of astaxanthin in a single-step operation.

Characterization of alcohol/salt aqueous two-phase system for optimal separation of gallic acids

Gallic acid (GA) is a hydrophilic polyphenol which is noteworthy for strong antioxidant capacity. The drawbacks of conventional extraction approaches such as time-consuming and high processing cost are often viewed as a hurdle to extract GA from plant sources in industrial scale. Aqueous two-phase system (ATPS) is a separation approach which can be employed as an alternative to the conventional approaches. The partition behaviour of GA in an alcohol/salt ATPS was investigated in this study to aid the development of industrial scale ATPS to extract GA from natural sources. The separation of GA was characterized by determining the types of alcohol and salt, phase composition, sample load, pH of the system and addition of adjuvants applied in the alcohol/salt ATPS construction. The hydrophilic GA was targeted to the salt-rich phase of the alcohol/salt ATPS with a partition coefficient (K_GA) of 25.00 ± 0.00. The optimum condition of ATPS for the maximum partition of GA was achieved in ATPS comprised of 24% (w/w) 1-propanol and 22% (w/w) phosphate salt at pH 8 with 5% (w/w) of 1 mg/mL sample loading and 2% (w/w) NaCl addition. The findings suggest that ATPS can be applied for separation of GA from various natural sources.

Efficacy of alcohol/sugar aqueous biphasic system on partition of bovine serum albumin

The efficacy of alcohol/sugar aqueous biphasic (ABS) system on protein extraction was investigated. A model protein, bovine serum albumin (BSA), was adopted to evaluate the effects of types and concentration of phase-forming components, protein concentration, and system pH on the protein partition efficiency. The 1-propanol/maltose ABS exhibited an overall better partition efficiency of BSA to the alcohol-rich top phase. A maximum partition coefficient (K) of 20.01 ± 0.05 and recovery yield (Y) of 95.42% ± 0.01% of BSA were achieved with 35% (w/w) 1-propanol/22% (w/w) maltose ABS at pH 5.0 for 10% (w/w) BSA load. The K and Y of BSA in 1-propanol/maltose ABS was slightly improved with the addition of 3% (w/w) of ionic liquid, 1-butyl-3-methylimidazolium bromide ([Bmim]Br) as the adjuvant that could provide protein stabilizing effect. The Fourier Transform Infrared Spectrum (FTIR) analysis revealed that the protein structure remained unaltered upon the separation process.