Monday, April 29, 2013
Exhibit Hall
Lipase-displaying whole cells proved to be an efficient biocatalyst because of their low preparation costs, simple recycling procedure and repeated reusing capacity. The combined utilization of Candida antarctica lipase B (CALB) and Rhizomucor miehei lipase (RML) displayed on Pichia pastoris cell surface separately, to produce biodiesel in co-solvent media was investigated. Response surface methodology incorporating a D-optimal design was employed to obtain the optimum reaction conditions for methyl ester (ME) synthesis. The synergistic effect of the two displayed lipases and the use of tert-butanol and isooctane as co-solvent media were found to significantly improve the transesterification reaction. Scaled-up reactions using various kinds of feedstock were carried out in a 0.5-l stirred reactor under optimum conditions, affording ME yields over 90% in 12 h. Moreover, the ME yields remained at more than 85% after 20 repeated batch cycles. In conclusion, this biocatalyst affords a promising route for efficient biodiesel production.