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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%. [ABSTRACT FROM AUTHOR]

Lysophospholipids, such as lysophosphatidic acid or lysophosphatidylcholine, are important bioactive lipids, involved in various normal and pathological cellular processes. They also have industrial and pharmaceutical uses such as emulsifiers or components of drug delivery systems. Lipases, which natural substrates are long chain triacylglycerols, are important biocatalysts for organic synthesis mainly due to their broad substrate specificity and their ability to display high catalytic activity in organic media. This paper describes the various lipase-catalyzed reactions implemented for the production of lysophospholipids. They include hydrolysis or alcoholysis of phospholipids and acylation of the glycerophosphoryl moiety. Special emphasis is made on our work dealing with the production of lysophospholipids rich in dososahexaenoic acid, an important dietary polyunsaturated fatty acid via the hydrolysis of phospholipids extracted from the microalga Isochrysis galbana.

Marine microalgae are now well-known for their ability to produce omega-3 long chain polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Among these microalgae, Isochrysis galbana has received increasing interest especially because of its high DHA content and its common use in hatchery to feed fish larvae and clams. Moreover, lipolysis occurring from the biomass harvest stage suggests that I. galbana may contain lipolytic enzymes with potential interesting selectivities. For these reasons, the potential of this microalga for the production of valuable lipids and lipolytic enzymes was investigated. Lipid analysis revealed that DHA is mainly located at the sn-2 position of the phospholipids. Thus, I. galbana was considered as an interesting starting material for the lipase catalyzed production of 1-lyso-2-DHA-phospholipids which are considered as convenient vehicles for the conveyance of DHA to the brain. Lipids from I. galbana can also be used for the enzyme-catalyzed production of structured phospholipids containing one DHA and one medium chain fatty acid in order to combine interesting therapeutic and biological benefits. Starting from total RNA extract from I. galbana, coding sequences of putative lipolytic enzymes were obtained by RACE and Nested PCR. The heterologous expression of a sequence designated IgTeCe was implemented. An expression plasmid was constructed by ligating the coding sequence to a plasmid vector and then cloned and expressed in E. coli. Results showed the effective functionality of plasmid construction for the production of a recombinant protein with the expected molecular mass. Moreover, local alignment using BLASTP and biochemical evidences support the hypothesis that the expressed protein is a thioesterase.