|Hsu, An Fei
Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2003
Publication Date: 10/11/2003
Citation: Hsu, A.C., Jones, K.C., Foglia, T.A., Marmer, W.N. 2003. Optimization of alkyl ester production from grease using phyllosilicate sol-gel immobilized lipase. Biotechnology Letters. 25:1713-1716.
Interpretive Summary: Biodiesel is the term applied to the simple mono-alkyl esters of vegetable oils and fats (typically methyl and ethyl esters) when used as diesel engine fuels. There is a growing interest in biodiesel because in addition to its being an alternative renewable fuel it also improves the emissions of diesel-powered vehicles. Since feedstock cost is the major component in making biodiesel, there is interest in producing biodiesel from the least expensive lipid feedstocks. To this goal, alternative enzymatic methods to make biodiesel from low-cost feedstock, namely recycled restaurant grease, have been investigated. It is imperative, however, when using this biocatalytic approach that the expensive biocatalyst is immobilized for reusability and to make the process a continuous one. In this paper, we describe the optimal processing conditions required for the production of biodiesel using an immobilized lipase. The technology described herein is needed for the development of the continuous commercial production of biodiesel from recycled restaurant grease.
Technical Abstract: Simple alkyl ester derivatives of restaurant grease were prepared using a lipase from Pseudomonas cepacia immobilized within a phyllosilicate sol-gel matrix as biocatalyst. Alcoholysis reactions of grease were carried out in solvent-free media using a one step addition of alcohol to reaction mixture. Reaction products were analyzed by high performance liquid chromatography. The effect of reaction parameters such as temperature, solvent, substrate ratio, and amount of enzyme used on ester yields was investigated. Results indicated that the immobilized lipase was active over the temperature range of 40-70°C. Ester yields were highest when the molar ratio of reactants (grease to alcohol) used was 1:4 and the amount of biocatalyst used was 10 wt% of grease. Alcoholysis reaction conditions were optimized for the continuous production of simple esters of grease for use as biodiesel.