Continuous production of monoacylglycerols by glycerolysis of palm olein with immobilized lipase

Nine commercial lipases from Pseudomonas sp. (lipase PS), Pseudomonas fluorescens (lipase AK), Candida rugosa (lipase AY), Rhizopus delemar (lipase D), Mucor javanicus (lipase M), Rhizopus oryzae (lipase F), C. rugosa (lipase OF) Alcaligenes sp. (lipase PL) and Chromobacterium viscosum (lipase LP) were screened for production of monoacylglycerols (MAG). Lipase PS was the most suitable enzyme for glycerolysis of palm olein with glycerol. This lipase had hydrolytic activity 10.42 U/mg and provided a high yield of MAG with 28.05% at 45 °C. Celite, silica gel, CaCO3, Accurel EP100 and activated charcoal were used as supports to immobilize lipase PS. Accurel EP100 (<200 μm) was the best support. The optimum conditions for immobilization included the enzyme concentration of 50 U/ml and immobilization temperature at 30 °C for 30 min. When 5.0 ml enzyme solution was mixed with 0.5 g support the immobilized activity was 0.23 U/mg support and immobilized yield was 45.38%. The immobilized lipase PS (IM-PS) on Accurel had optimal activity at 45-65 °C and more than 90.0% of the activity remained after incubated at 45 °C for 24 h. In batch production 20.74% MAG was obtained at 45 °C for 24 h. The continuous production of MAG was performed with IM-PS (350 U) in the packed-bed reactor (PBR) (0.68 cm ID, 25 cm long) and a continuous stirred-tank reactor (CSTR) (4.5 cm ID, 6.0 cm height) for 96 h at 45 °C. When the flow rate of the substrate mixture was 0.02 ml/min the average yields of MAG were 14.01 and 14.34% in PBR and CSTR, respectively.