High-level expression and biochemical characterization of a novel cold-active lipase from Rhizomucor endophyticus

Abstract

To identify novel cold-active lipases from fungal sources and improve their production by heterologous expression in Pichia pastoris. A novel cold-active lipase gene (ReLipB) from Rhizomucor endophyticus was cloned. ReLipB was expressed at a high level in Pichia pastoris using high cell-density fermentation in a 5-l fermentor with the highest lipase activity of 1395U/ml. The recombinant lipase (RelipB) was purified and biochemically characterized. ReLipB was most active at pH 7.5 and 25°C. It was stable from pH 4.5-9.0. It exhibited broad substrate specificity towards p-nitrophenyl (pNP) esters (C2-C16) and triacylglycerols (C2-C12), showing the highest specific activities towards pNP laurate (231U/mg) and tricaprylin (1840U/mg), respectively. In addition, the enzyme displayed excellent stability with high concentrations of organic solvents including cyclohexane, n-hexane, n-heptane, isooctane and petroleum ester and surfactants. A novel cold-active lipase from Rhizomucor endophyticus was identified, expressed at a high level and biochemically characterized. The high yield and unique enzymatic properties make this lipase of some potential for industrial applications.