Valorization of Oilseed Cake through the Isolation of Cellulose by Autohydrolysis

Abstract

Oilseed cakes are by-products of the oil extraction process that are commonly used as animal feed due to their high protein content. However, they can be valorized also in other ways producing for instance protein isolates or bioenergy. In this work, the application of a lignocellulosic fractionation process on an oilseed cake to recover cellulose is tested. Indeed, oilseed cake can have a relevant content of cellulose that can be isolated. It is important to point out that the first hydrolysis step is carried out as an auto-hydrolysis novel process instead of a conventional mild acid hydrolysis to reduce the environmental impact of the process itself. The first aim of this work is to investigate, discuss and verify the applicability of such a fractionation process on oilseed cake. In addition, to further reduce the potential environmental impact of the process, the effects of variation of both NaOH concentration and temperature in the alkaline hydrolysis are investigated and discussed as the second aim. Therefore, experimental tests are carried out at three different NaOH concentrations (i.e., 1.5, 4.0, 16.0% v/v) and two different temperatures (i.e., 25 and 60°C) to make an initial assessment of the optimal conditions for cellulose recovery and reduced environmental impact.