Integrated bioprocess for structured lipids, emulsifiers and biodiesel production using crude acidic olive pomace oils

Olive pomace oil (OPO), a by-product of olive oil industry, is directly consumed after refining. The novelty of this study consists of the direct use of crude high acidic OPO (3.4-20% acidity) to produce added-value compounds, using sn-1,3-regioselective lipases: (i) low-calorie dietetic structured lipids (SL) containing caprylic (C8:0) or capric (C10:0) acids by acidolysis or interesterification with their ethyl esters, (ii) fatty acid methyl esters (FAME) for biodiesel, and (iii) sn-2 monoacylglycerols (emulsifiers), as by-product of FAME production by methanolysis. Immobilized Rhizomucor miehei lipase showed similar activity in acidolysis and interesterification for SL production (yields: 47.8-53.4%, 7 h, 50celcius) and was not affected by OPO acidity. Batch operational stability decreased with OPO acidity, but it was at least three-fold in interesterification that in acidolysis. Complete conversion of OPO into FAME and sn-2 monoacylglycerols was observed after 3 h-transesterification (glycerol stepwise addition) and lipase deactivation was negligeable after 11 cycles.

Automated summary

This study investigates the direct utilization of high acidic olive pomace oil (OPO) to produce added-value compounds using lipases. The results demonstrate the successful production of low-calorie dietetic structured lipids, biodiesel, and emulsifiers from OPO. The immobilized Rhizomucor miehei lipase shows high activity in acidolysis and interesterification, with minimal impact from OPO acidity. Complete conversion of OPO into fatty acid methyl esters and sn-2 monoacylglycerols is achieved through transesterification, with negligible lipase deactivation after multiple cycles.