Primary purification of intracellular Halomonas salina ectoine using ionic liquids-based aqueous biphasic system

Ectoine is a zwitterionic amino acid derivative that can be naturally sourced from halophilic microorganisms. The increasing demands of ectoine in various industries have urged the researches on the cost-effective approaches on production of ectoine. Ionic liquids-based aqueous biphasic system (ILABS) was applied to recover Halomonas salina ectoine from cells hydrolysate. The 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim)BF₄ was used in the ILABS and the recovery efficiency of ILABS to recover ectoine from H. salina cells lysate was evaluated by determining the effects of phase composition; pHs; crude loading and additional neutral salt (NaCl). The hydrophilic ectoine was targeted to partition to the hydrophilic salt-rich phase. A total yield (Y_B) of 96.32% ± 1.08 of ectoine was obtained with ILABS of phase composition of 20% (w/w) (Bmim)BF₄ and 30% (w/w) sulfate salts; system pH of 5.5 when the 20% (w/w) of crude feedstock was applied to the ILABS. There was no significant enhancement on the ectoine recovery efficiency using the ILABS when NaCl was added, therefore the ILABS composition without the additional neutral salt was recommended for the primary purification of ectoine. Partition coefficient (K_E) of 30.80 ± 0.42, purity (P_E) of 95.82% and enrichment factor (E_f) of 1.92 were recorded with the optimum (Bmim)BF₄/sulfate ILABS. These findings have provided an insight on the feasibility of recovery of intracellular biomolecules using the green solvent-based aqueous system in one single-step operation.