Enzyme assisted oil extraction from fishery by products: insight gained from interfacial phenomena

Enzyme assisted oil extraction (EAOE) is a green scalable method to recover oil from marine products and byproducts alike. In EAOE enzymes are used in order to break the cell walls and release the oil entrapped in the cells and facilitate extraction. Besides the positive aspects of EAOE both the enzymes and the products of their reaction adsorb at the interface and often the literature refers to emulsification problems and demulsification actions to improve oil recovery. Since interfacially active molecules come into play the interfacial properties should play a significant role in oil recovery. This work aims to shed more light on the effect of interfacial phenomena on oil recovery. As an example, EAOE from Nototodarus sloanii by-products is performed using Alcalase®, oil recovery is determined as a function of enzyme contact time, whereas the of oil droplet size and distribution within the by-products-enzyme medium is examined via Confocal Lazer Microscopy. To understand the changes in oil droplet distribution and oil recovery the competitive adsorption of surface active species and the enzyme as well as the mechanical properties of the interface the dynamic interfacial tension at the oil water interface is determined under static conditions and after mechanical deformations within the linear viscoelastic regime. It is found that there is a correlation between the interfacial properties and oil recovery which could explain the changes in oil recovery as a function of enzyme action time • Oil droplet size, shape and distribution changes affected by enzyme incubation time • Oil-water interfacial tension reflects protein, enzyme and hydrolysate adsorption • Relaxation behavior of the interface was related to oil extractability