Expression and characterization of an organic solvent tolerant recombinant lipase from Staphylococcus capitis SH6 for food wastewater treatment

Abstract

The study illustrated here aims on an organic solvent tolerant lipase from Staphylococcus capitis (SCL). The gene part, encoding the mature lipase, was cloned and sequenced. The concluded polypeptide sequence, equivalent to the protein, consist of 388 amino acid residues with a molecular mass of about 45 kDa. A structure-based alignment of the SCL amino acid sequence shows high identities with those many staphylococcal lipases. From this alignment of sequences, the catalytic triad (Ser 117, Asp 308 and His 347) of SCL could be identified. The mature part of the SCL was expressed in Escherichia coli and the recombinant lipase (r-SCL) was purified to homogeneity. The purified r-SCL presented a quite interesting stability at low temperatures (< 30 °C) and the enzyme was found to be highly stable in polar organic solvent and at a pH ranging from 3 to 12. After that, we have demonstrated that the recombinant enzyme may be implicated in the biodegradability of oily wastewater from effluents of fast-food restaurants; the maximum conversion yield into fatty acids obtained at 30 °C, was 65%.

Keywords:

• Biodegradation
• heterogeneous expression
• oily wastewater
• organic solvent tolerant lipase
• pH stability
• purification

Acknowledgments

This work is a part of a doctoral thesis by Fatma RMILI whose research was financially supported by ministry of higher education and scientific research (Tunisia) through a grant to Laboratory of Biochemistry and Enzymatic Engineering of Lipases - Engineering National School of Sfax (ENIS).

Authors’ contributions

Fatma Rmili, Dr Celine Loiseau and Pr Ahmed Fendri conceived the presented idea. Fatma Rmili prepared the manuscript. Dr Najeh Krayem, Dr Laurent Gauvry, Dr Fakher Frikha and Pr Ahmed Fendri contributed to the analysis of the results. Pr Ahmed Fendri, Pr Mohamed Chamkha, Pr Adel Sayari and Pr Françoise Ergan supervised the findings of the work. All authors approved the final draft of the manuscript.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.