Immobilized phospholipase enzyme soybean oil refinement

Removal of phospholipids and associated metals is also a requirement for edible soybean oil and protection of hydrogenation catalysts for the hydrotreating of vegetable oil. A one step process was developed which shows high efficacy in the removal of phospholipids and associated metal contaminants from vegetable oils. This method is predicated on the removal of the phospholipids through chemical lysing achieved by immobilized phospholipase enzymes. The resulting lysed phospholipid is more polar allowing it to wash into the heavy phase composed of gums (phospholipids) and aqueous which is subsequently removed from the oil under centrifugation. An additional benefit of this process is the lysed phospholipids entrain less oil than intact phospholipids resulting in higher oil yield. This method has been successfully tested in an industrial setting processing crude soybean oil.

The process uses an enzymatically active solid-state reactor to convert phospholipids to water soluble components which in turn, partition into the aqueous phase. The subsequent separation process removes the water-soluble components from the oil phase producing oil clean enough for direct hydrogenation into sustainable aviation fuel/renewable diesel or edible oil production (Table 1). Augmentation of phospholipid hydrolysis using post-column procedures is in development and promises to help tailor performance for different industrial ends.

Significant advantages of this process include:

- Simple one step process for contaminant removal

- Reduction/elimination of bleaching clay and silica

Table 1. Concentration of elements in parts per million at different steps of crude soybean oil cleanup.