Effects of organic solvent, water activity, and salt hydrate pair on the sn-1,3 selectivity and activity of whole-cell lipase from Aspergillus niger GZUF36

Abstract

We previously screened a whole-cell lipase EC 3.1.1.3 from the novel strain Aspergillus niger GZUF36, which exhibited 1,3-selectivity in the synthesis of 1,3-diacylglycerol via glycerolysis. However, the mechanism of lipase selectively in catalyzing the sn-1,3 position remains ambiguous. This work was performed to investigate the 1,3-selective mechanism of lipase using glycerolysis to synthesize 1,3-diacylglycerol (1,3-DG) as a model reaction by changing solvent(s) and water activity (a), and addition of salt hydrate pair. The measured diacylglycerol yield was also used to examine lipase activity. Results indicated that not only organic solvent and a have strong effect on the sn-1,3 selectivity, but also ions of salt hydrate pair also affected selectivity. Lipase conformation was altered by hydrophobic interactions of the solvent, a, or ions of salt hydrate, resulting in distinct sn-1,3 selectivity of the lipase. The salt hydrate pair changed the lipase conformation and selectivity not only by a but also by static interactions, which was rarely reported. These parameters also affected lipase activity. The lipase displayed the highest selectivity (about 88%) and activity in solvents of t-butanol and n-hexane (1:29, v/v) at a 0.43. The results demonstrated that the sn-1,3 selectivity and activity of the lipase from A. niger GZUF36 may be improved by control of some crucial factors. This work laid a foundation for the application of lipase in the synthesis of 1,3-DG and other structural and functional lipids.

Novel and Efficient Synthesis of Phenethyl Formate via Enzymatic Esterification of Formic Acid

“…Nine different solvents were chosen for the optimization of the Novozym 435-catalyzed esterification reaction. Almost all lipases have a hydrophobic lid attached to their active sites; i.e., they are activated, when the lid is opened in an organic solvent or oil-water surface, but not in an aqueous environment [48,49]. Therefore, only commonly used organic solvents were selected for the reaction [18,20].…”

Sorption characteristics of flour mixtures enriched with grape seeds flour of Bulgarian and French raw materials

“…Water excess or shortage can lead to premature food spoilage (Hammerer et al, 2018). Furthermore, that primary indicator is monitored at different stages and at different frequencies (Li et al, 2018). Water activity plays an important role in the growth and development of the microorganisms as well as in the technological and thermo-physical properties of the products (Muangrat and Nuankham, 2018).…”

Kinetics and Mechanism of Solvent Influence on the Lipase-Catalyzed 1,3-Diolein Synthesis

“… 17 − 19 Li et al studied the effect of organic solvents on the activity and sn-1,3 selectivity of whole-cell lipase from Aspergillus niger GZUF36; the lipase showed higher activity in hydrophobic solvents than that in hydrophilic solvents, and the lipase may appear excellent sn-1,3 selectivity only in proper hydrophobic solvents. 20 …”