Lipase production by Botryosphaeria ribis EC-01 on soybean meal supplemented with amino acids, and some physicochemical properties of the enzyme

Abstract

The amino acids that form the chemical structure of several lipase catalytic triads (serine, histidine, glutamic or aspartic acid), as well as glycine, were added to soybean meal in distilled water as nutrient for Botryosphaeria ribis EC-01 to produce lipase under submerged fermentation. The addition of glutamic acid at 0.01% concentration increased lipase activity by 60% (2,684 U/gss), while at 0.1% the increase was 80% (3,039 U/gss) by comparison with the control (1,690 U/gss). Glycine also stimulated lipase production on this medium increasing the enzyme production by 31 % (25 UmL-1) by comparison to the control (19 UmL-1). The optimal pH of this lipase was 8.0 in phosphate buffer, and was stable in the pH range (3–10), while the optimal temperature was 55°C. The fungal lipase remained active in methanol, ethanol and glycerol at concentrations of 25, 10 and 50% (v/v), respectively. The addition of the cations Ba2+, Mg2+ and Mn2+ increased lipase activity, while Fe3, Cu2+ and Hg2+ partially inhibited the enzyme. Some kinetic properties demonstrated that B. ribis EC-01 lipase was a true lipase preferring long chain fatty acyl esters as substrates. These properties make B. ribis EC-01 lipase attractive for use in the production of biodiesel.

Keywords

• enzyme production, submerged fermentation, agro-industrial waste residues, kinetic properties