Biodiesel production from microalgae oil by lipase from Pseudomonas aeruginosa displayed on yeast cell surface

Yeast surface display has become a powerful technology in recent decades and one of the promising areas in this field is the biodiesel synthesis by microbial lipases. Hence, in this study the optimized lipase A (Lip A) gene from Pseudomonas aeruginosa was fused to GPI-anchored protein Gcw61 and successfully displayed on the surface of Pichia pastoris X33. A lipase activity of 85.2 U/mg dry cell weight was obtained from recombinant P. pastoris. The copy numbers of inserted lipase gene were determined 2.09 ± 0.06 by real time PCR absolute quantification method. The enzyme showed the best stability in pH 7.0–10.0 and at temperature 37 °C–40 °C and was also stable in hydrophilic organic solvents. Ca2+, Mg2+, Mn2+ and Cu2+ ions enhanced enzyme activity, whereas Fe2+ and Zn2+ ions and some detergents like SDS, CTAB, Tween 20 and 80 dramatically decreased the activity of the enzyme. The results demonstrate that our whole cell biocatalyst exhibited a good potential for biodiesel production from microalgae oil in 10 repeated batch cycles.