Partial characterization of Bacillus pumilus catalase partitioned in poly(ethylene glycol)/sodium sulfate aqueous two-phase systems

Abstract

Aqueous two-phase partitioning system (ATPS) was used to extract and purify catalase from Bacillus pumilus. The system parameters for effective purification of catalase were optimized. The best catalase recovery (123%) with a 4.6-fold purification was obtained in the bottom phase of ATPS including the mixture of 15% (w/w) PEG4000, 10% (w/w) Na₂SO₄ and 3% (w/w) NaCl at pH 5.0. The purified enzyme was characterized regarding its activity and stability. The highest enzyme activity was observed at pH 7.0 and 37 °C on hydrogen peroxide. The enzyme was quite stable at temperatures between 30 and 55 °C and a pH range of 7.0–9.0. The K_m and V_max values were determined from Lineweaver–Burk plot as 11 mM and 1667 µmole ml⁻¹min⁻¹, respectively. Overall, it can be said that ATPS is a rapid, reasonable, straightforward and cost-effective process for catalase purification in comparison to the chromatographic methods.

Keywords:

• Activity
• aqueous two-phase system
• Bacillus pumilus
• catalase
• characterization
• purification

Acknowledgments

The authors would like to express their sincere thanks to Kocaeli University for financial support. Also many thanks to Dr. Yonca Duman and Dr. Arda Acemi for their inspiring discussions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study has been funded by the Kocaeli University Research Foundation under BAP Project No 2017/57.