Primary recovery of lipase derived from Burkholderia cenocepacia strain ST8 and recycling of phase components in an aqueous two-phase system

摘要

The recovery of Burkholderia cenocepacia (B. cenocepacia) strain ST8 lipase has been investigated using a recycling aqueous two-phase system (ATPS) consisting of the thermoseparating random copolymer ethylene oxide-propylene oxide (EOPO) and potassium phosphate. In the primary ATPS, lipase was satisfactorily partitioned to the polymer-rich top phase in the system composed of EOPO 3900 with a tie-line length (TLL) of 48.5% (w/w), a volume ratio (V_R) of 2.3 and a crude load of 20% (w/w) at pH 7. In the secondary system, the polymer-rich top phase from the primary ATPS was isolated and subjected to thermo-induced phase separation. After thermoseparating, a concentrated solution of EOPO copolymer was formed in the bottom phase, and a water solution containing lipase was formed in the top phase of this secondary two-phase system. Recycling of the components was accomplished by mixing the concentrated polymer recovered from the secondary system and the phosphate solution recovered from the primary system. The average purification factor of lipase and the yield obtained from the four successive purifications were 14 and 99%, respectively. There was no significant difference in the purification factor, yield or partitioning efficiency of purified lipase obtained using fresh or recycled chemicals in the ATPS.