ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Purification and characterization of an extracellular lipolytic enzyme from the fermented fish-originated halotolerant bacterium, Virgibacillus alimentarius LBU20907

Sawitree Dueramae, Preeyanuch Bovornreungroj, Toshiki Enomoto, and Duangporn Kantachote

Department of Microbiology, Faculty of Science, Prince of Songkla University, Songkhla, Thailand

E-mail: preeyanuch.b@psu.ac.th

Abstract: A halotolerant Virgibacillus alimentarius LBU20907 isolated from fermented fish (Budu) was found to be an efficient producer of extracellular halophilic lipase enzyme. The enzyme was purified 5.99-fold with a 0.15% final yield to homogeneity by ammonium sulfate precipitation, followed by dialysis, Toyopearl DEAE-650 M ion exchange chromatography, Toyopearl butyl-650 M hydrophobic interaction chromatography, and Toyopearl-HW 55 F gel filtration chromatography. SDS-PAGE of purified lipase exhibited a homogenous single band with a very high molecular weight of 100 kDa. The properties of purified lipase revealed maximum activity at pH 7.0 and 40 °C. It was also highly stable in a pH range of 6.0–7.0, retaining more than 90% activity for 24 h. It was stable at the temperature of 30–50 °C and maintained more than 80% activity for 16 h. The purified lipase performing the maximal activity in the presence of 20.0% NaCl indicated halophilic enzyme properties. Its lipolytic activity was highest against p-nitrophenyl palmitate. The lipase activity was found to be enhanced in hexane. The enzyme activity was stimulated in the presence of Zn²⁺, Ca²⁺, Mg²⁺, and Sr²⁺; while, it was completely inhibited by Ba²⁺ and Co²⁺. The enzyme had a K_m and V_max of 108.0 mg and 79.1 U mL⁻¹, respectively.

Keywords: Halophilic lipase; Purification; Enzyme properties; Virgibacillus alimentarius

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-017-0191-y

Chemical Papers 71 (10) 1975–1984 (2017)