Biolubricant production from palm stearin through enzymatic transesterification method

Abstract

The present study aims to develop environmentally benign lubricant from by-product of palm oil processing through enzymatic reaction. Candida antartica lipase was employed as catalyst to transesterified reaction between palm stearin and methanol in a solvent-free system. The reaction parameters were varied in terms of molar ratio of methanol-to-palm stearin (3:1 to 8:1), temperature (between 40 and 70 °C), time (2–12 h)and concentration of catalyst (from 2 to 10 wt.%). Enzymatic transesterification demonstrated around 95.26% maximum yield of palm stearin methyl ester under the following conditions: 4:1 methanol-to-PS molar ratio, reaction temperature of 60 °C, reaction time of 8 h and 6.0 wt. % of lipase concentration. The Structural modification of palm stearin resulted in improvement in both physicochemical and tribological properties. The produced biolubricant demonstrated superior viscosity index (>120)and friction properties over commercial mineral oil-based lubricant. This study showed that lubricant derived from palm stearin has a great potential to be used as a base stock in regard to favourable biodegradability and tribological performance.