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.

A green bio-separation alternative can be performed with a non-toxic and biodegradable aqueous biphasic system (ABS) composed of short-chain aliphatic alcohol-based top phase (1-propanol and 2-propanol) and carbohydrate-based bottom phase (glucose, sucrose, and maltose). A model protein, bovine serum albumin (BSA) was adopted to determine the effects of types and concentration of phase-forming components; protein concentration; and system pH on the protein partition efficiency in the ABS. Results showed that the 1-propanol/maltose ABS gave an overall better partition efficiency of BSA to the alcohol-rich top phase compared to the 1-propanol/sucrose ABS, 1-propanol/glucose ABS, and 2-propanol/sugar ABS attributed to the lower hydrophilicity of 1-propanol and the stronger sugaring-out effect exerted by the maltose. A maximum partition coefficient (K) of 20.01 ± 0.05 and recovery yield (Y) of 95.42% ± 0.01 of BSA were obtained with the 35% (w/w) 1-propanol/22% (w/w) maltose ABS at pH 5.0 which contained 10% (w/w) BSA. The K and Y of BSA in 1-propanol/maltose ABS was further enhanced with the addition of 3% (w/w) of ionic liquids, 1-butyl-3-methylimidazolium bromide ([Bmim]Br) as the adjuvants which provides the protein stabilizing effect. The Fourier Transform Infrared Spectrum (FTIR) analysis revealed that the protein structure remained unaltered upon the separation process.