Potential plant oil feedstock for lipase-catalyzed biodiesel production in Thailand

Twenty-seven types of plants found to contain more than 25% of oil (w/w) were selectively examined from 44 species. Saponification number (SN), iodine value (IV), cetane number (CN) and viscosity (η) of fatty acid methyl esters (FAMEs) of oils were empirically determined, and they varied from 182 to 262, 3.60 to 142.70, 39.32 to 65.80 and 2.29 to 3.95, respectively. Fatty acid compositions, IV, CN and η were used to predict the quality of FAMEs for use as biodiesel. FAMEs of plant oils of 15 species were found to be most suitable for use as biodiesel by meeting the major specification of biodiesel standards of Thailand, USA and European Standard Organization. The oils from these 15 species were further investigated for the conversion efficiency of biodiesel in lipase-catalyzed transesterification reaction with Novozyme 435 and Lipozyme RM IM. Oils of four species, palm (Elaeis guineensis), physic nut (Jatropha curcas), papaya (Carica papaya) and rambutan (Nephelium lappaceum), can be highly converted to biodiesel by transesterification using Novozyme 435- or Lipozyme RM IM-immobilized lipase as catalyst. Therefore, these selected plants would be economically considered as the feedstock for biodiesel production by biocatalyst.