Biodiesel production from woody oil catalyzed by Candida rugosa lipase in ionic liquid

• Ionic liquid helped to boost efficiency of CRL from about 35% to 96.2%.
• CTK oil was proved suitable for biodiesel preparation with 96.2% conversion yield.
• Fuel properties of biodiesel met the standards set by ASTM and EN.
• HC and CO emissions of the biodiesel respectively decreased 52.7% and 48.6%.

In this study, biodiesel production from Chinese tallow kernel oil catalyzed by Candida rugosa lipase (CRL) in ionic liquid was investigated. Biodiesel was prepared from Chinese tallow kernel oil. Nineteen kinds of ionic liquids were screened for CRL to enhance its catalysis ability for biodiesel synthesis. Interestingly, [Hmim][PF6], not only help to simplify the downstream processing, but also boost the efficiency of CRL from about 35% to 95.4%. In addition, the biodiesel mixed with various blending ratios of fossil diesel was used to fuel the conventional diesel engine to examine fuel and emission properties. Most of fuel characteristics of the biodiesel met the standards set by EN and ASTM. Its output power was found to be close to pure diesel. The emission products, including hydrocarbons (HC, 52.7% lower) and carbon monoxide (CO, 48.6% lower), decreased substantially with the exception of oxynitride (NOx) emission, which displayed a 12.8% increase. The results suggest that biodiesel production from woody oil catalyzed by CRL in [Hmim][PF6], is feasible in future application with a promising prospect.