Process for enzymatically degumming vegetable oil

A process for degumming vegetable oil, which comprises the steps of:

• (a) adjusting the pH of the vegetable oil with an aqueous acid to a value of 3 to 6 to obtain a vegetable oil-water emulsion;
• (b) dispersing throughout the vegetable oil-water emulsion an aqueous enzyme solution which contains at least one of the enzymes phospholipase A1, A2 or B to enzymatically degum the vegetable oil;
• (c) stirring the vegetable oil-water emulsion to facilitate enzymatic degumming of the vegetable oil at a temperature of 20.degree. to 90.degree. C. to obtain a liquid which contains degummed vegetable oil and a watery sludge containing said phospholipase enzymes which were used during step (b) and which are adsorbed on a phosphatide sludge;
• (d) separating the degummed vegetable oil from the watery sludge which contains said phospholipase enzymes which were used during step (c) and which are adsorbed on said phosphatide sludge to obtain degummed vegetable oil and a water-sludge phase containing said used phospholipase enzymes adsorbed on said phosphatide sludge;
• (e) adding a separation promoter selected from the group consisting of a polyethylene-sugar-fatty acid ester, ricinus ethoxylate, ethoxylated palmitate, an ethoxylated synthetic primary alcohol, an ethoxylated tallow fatty alcohol, a non-ionic surfactant, a hot water-soluble methyl cellulose, a hot water-soluble carboxymethylcellulose, a water-soluble starch, a xerogel, an alginate and a chitosan to said water-sludge phase following step (d) to promote separation of the used enzymes from the phosphatide sludge by desorption, and separating an aqueous solution of said used phospholipase enzymes from said phosphatide sludge to form a sludge-free aqueous solution containing the used phospholipase enzymes or
• (e1) adding a solubilizer selected from the group consisting of a polyethylene-sugar-fatty acid ester, ricinus ethoxylate, ethoxylated palmitate, an ethoxylated synthetic primary alcohol, an ethoxylated tallow fatty alcohol, and a non-ionic surfactant to said watery sludge before step (d) or to said water-sludge phase following step (d) to solubilize said phosphatide sludge thereby also forming a sludge-free aqueous solution containing the used phospholipase enzymes;
• (f) recovering the sludge-free aqueous solution containing the used phospholipase enzymes from step (e) or step (e1);
• and
• (g) recycling at least in part to step (b) said aqueous solution containing the used phospholipase enzymes wherein said aqueous solution is dispersed throughout a fresh supply of the vegetable oil to be degummed according to step (c), and wherein the content of recycled used phospholipase enzymes in the total amount of phospholipase enzymes dispersed in the vegetable oil is at least 10%.