Preparation of a promising whole cell biocatalyst of Geotrichum sp. lipase and its properties

Abstract

BACKGROUND: As a new protein expression and self-immobilization system, cell-surface displayed enzymes have attracted increasing attention. In this study, Geotrichum sp. lipase (GSL), an important enzyme for the enrichment of polyunsaturated fatty acids (PUFAs), was first displayed on the cell surface of Saccharomyces cerevisiae. RESULTS: The activity of displayed GSL was higher (43.7 U g−1 dry cell) than that of Candida antarctica lipase B (26.26 U g−1 dry cell) and that of Rhizopus oryzae lipase (4.1 U g−1 dry cell). It also exhibited higher thermostability than the free lipase, and retained 89% of the original activity after incubation at 40 °C for 3 h, compared with 48% at 35 °C for the free lipase at pH 8.5. Interestingly, the displayed lipase had a wider pH range and better pH stability. It had higher activity at all pH values than the free GSL, and retained 86% of the original activity in the pH range 9.5 to 10.5, whereas the activity of the free GSL could not be detected at pH 10. CONCLUSION: This work presented a method to prepare a whole-cell biocatalyst with better stability and broader pH tolerance which will provide a useful strategy for other cost-effective self-immobilized industrial lipases. Copyright © 2011 Society of Chemical Industry