Characterization of a solvent tolerant lipase from Aspergillus niger MYA 135

ROMERO, CINTIA MARIANA; LOTO, FLAVIA; PERA, LICIA MARÍA; BAIGORI, MARIO DOMINGO

Puerto Madryn

Congreso; 46 th Annual Meeting SAIB; 2010

SAIB

Lipase catalyses the hydrolysis of triglycerides at the oil-water interfaces. This reaction is reversible and the enzyme also catalyses the synthesis of esters in microaqueous conditions. Previously, we reported the presence of three enzymatic bands with lipolytic activity from Aspergillus niger MYA 135 olive oil-induced supernatant. In the present work, we selected lipase 1 for its purification and characterization, especially for its stability in the presence of various organic solvents. This activity was purified by two methods, electro-elution and DEAE-Sepharose anionexchange chromatography leading for each one to 8.4-fold and 47% and 16.6-fold and 53.4% of purification and recovery, respectively. Lipase 1 showed the following main characteristics: maximum activity at 37°C, pH 7.0; molecular mass, 68 KDa; pI 5.1; and a Km value of 0.99 mM for C18 (p-NP stearate). The purified lipase was also digested with trypsin and analyzed by HPLC-MS/MS. The sequences of the peptides did not show similarity with other lipases. Concerning the reactivity of this enzyme in a solvent free medium, a transesterification activity value of 0.78 ± 0.01 U/L was obtained yielding ethyl stearate as a product. Thus, these results show a valuable solvent-tolerant lipase for biodiesel production.