Experimental evaluation of a polystyrene sulphonic acid resin catalyst in the hydrolysis of low-grade lipids from the meat processing industry

Abstract

In this study, a polystyrene sulphonic acid resin catalysed hydrolysis of low grade lipids from meat processing waste, via an in-situ hydrolysis pathway was evaluated for enhanced fatty acid yield. Process evaluation was achieved using a response surface methodology based on a central composite design for four process variables (temperature, catalyst load, moisture mass fraction of the meat processing waste, and reaction time). This study enabled the development of a model that was sufficient to predict fatty acid yield as a function of the four process variables investigated. The optimum values of the temperature, catalyst loading, moisture mass fraction, and reaction time for enhanced fatty acid yield were determined to be 92.5 °C, a mass ratio of 0.09 resin to wet meat processing waste, 92%, and 1 h respectively. Catalyst recovery and regeneration were also demonstrated, with up to 88% mass fraction of the catalyst recoverable, while retaining an activity of 96% relative to the fresh catalyst. The study therefore showed that it is possible to produce high yields of fatty acids under moderate temperature conditions from high moisture low grade lipid sources. It was therefore shown that a highly efficient hydrolysis process can be achieved without the energetic penalty of preliminary drying operations that are associated with lipid extractive processes characterising existing lipid hydrolysis systems.