CONICET | Buscador de Institutos y Recursos Humanos

In the last few years, there has been a constant increase in the demand for oils to be used as a food and production of fuels. This demand has generated a need for cost-effective methods for removing contaminating phospholipids, known as gums, during the refining process. Traditionally, physical and chemical degumming methods have been used. More recently, developments were made to use enzymatic degumming, which possesses several advantages over chemical and physical methods such as minimal chemical waste and higher yields of refined oil. Type C phosholipases (PLCs) provide a higher extra yield of oil compared to traditional methods, both by generating 1,2-diacylglicerol (DAG) from phospholipids, which is miscible with triacylglycerols (TAGs), and by releasing the TAGs trapped as a consequence of the reduced volume of gums. Most of the PLCs reported in the literature for oil degumming have specificity for phosphatidylcholine (PC) and/or phosphatidylethanolamine (PE), which together represent ∼67% of the phospholipids present in soybean oil. Recently, we designed a novel PCPLC-Y, an engineered enzyme that can completely hydrolyze PC and PE. In this work, phosphatidylinositol-specific phospholipase C (PIPLC) candidates obtained from an in silico analysis were evaluated for oil degumming expecting to formulate this new enzyme in combination with PCPLC-Y in order to increase the efficiency of oil degumming. A PIPLC from Lysinibacillus sphaericus was shown to efficiently remove phosphatidylinositol, which represents ∼24% of the phospholipids in crude oil, and when combined with PCPLC-Y, the three major phospholipids present in crude oil were completely hydrolyzed, providing an extra yield of oil greater than 2.1%, compared to standard methods. A remarkably efficient fed-batch Escherichia coli fermentation process producing ∼14 g/L of the recombinant PIPLC enzyme was developed, which may facilitate the adoption of this cost-effective oil-refining process.