Purification, characterization and thermal inactivation kinetics of a non-regioselective thermostable lipase from a genotypically identified extremophilic Bacillus subtilis NS 8

Abstract

Thermostable lipase produced by a genotypically identified extremophilic Bacillus subtilis NS 8 was purified 500-fold to homogeneity with a recovery of 16% by ultrafiltration, DEAE-Toyopearl 650M and Sephadex G-75 column. The purified enzyme showed a prominent single band with a molecular weight of 45 kDa. The optimum pH and temperature for activity of lipase were 7.0 and 60°C, respectively. The enzyme was stable in the pH range between 7.0 and 9.0 and temperature range between 40 and 70°C. It showed high stability with half-lives of 273.38 min at 60°C, 51.04 min at 70°C and 41.58 min at 80°C. The D-values at 60, 70 and 80°C were 788.70, 169.59 and 138.15 min, respectively. The enzyme's enthalpy, entropy and Gibb's free energy were in the range of 70.07-70.40 kJ mol(-1), -83.58 to -77.32 kJ mol(-1)K(-1) and 95.60-98.96 kJ mol(-1), respectively. Lipase activity was slightly enhanced when treated with Mg(2+) but there was no significant enhancement or inhibition of the activity with Ca(2+). However, other metal ions markedly inhibited its activity. Of all the natural vegetable oils tested, it had slightly higher hydrolytic activity on soybean oil compared to other oils. On TLC plate, the enzyme showed non-regioselective activity for triolein hydrolysis.

Biochemical characterization of a new thermostable lipase from Bacillus pumilus strain

“…The same findings were described by fairolniza, the lipase from bacillus sp was thermostable in the temperature range of 55 to 75°C; and considerable activity (75%) was retained. Enzyme activity sequentially decreased as the incubation time is increased [31]; other lipase from bacillus subtilis was stable during 273.38, 51.04 and 41.58 min, at 60, 70 and 80°C and has an optimum activity in temperature of 60°C and stable in the pH of 7.0-9.0 and 40-70°C of temperature [32]. Due to the physicochemical properties of B. pumilus lipase, it can be the most efficient lipases and the best candidates in the industrial field [33].…”

An insight into microbial lipases and their environmental facet

“…The crystal structure of lipase from one such thermophilic organism, B. stearothermophilus, has been shown to contain a unique zinc-binding site, to which the organism's increased thermal stability might be attributed (Tyndall et al 2002). Certain strains of B. subtilis (Olusesan et al 2011) and B. coagulans (Kumar et al 2005) also produce lipases with thermo-tolerant attributes. The presence of charged residues and the formation of salt bridges play a key role in thermostability.…”

Partial Purification and Characterization of a Thermoalkalophilic Lipase Originated from Bacillus atrophaeus FSHM2 and its Application for Ester Synthesis

“…(Masomian et al, 2013). Isolates of Bacillus genera (B. subtilis DR8806 and B. subtilis NS8) have been found to produce lipases active at alkaline pH and in elevated temperature conditions (Olusesan et al, 2011;Emtenani et al, 2013). In the study conducted by Ghanem et al (2000) an alkalophilic thermostable lipase (optimally worked at 60°C and pH 10.6) isolated from Bacillus alcalophilus.…”