Continuous biodiesel conversion via enzymatic transesterification catalyzed by immobilized Burkholderia lipase in a packed-bed bioreactor

Methanolysis of sunflower oil catalyzed by a synthesized immobilized lipase (denoted as celite-alkyl-lipase) was carried out in a packed-bed reactor (PBR) (H = 167 cm, I.D = 1.5 cm) to produce biodiesel. Although complete conversion of the triglyceride can be achieved in a long-single column PBR with prolonged reaction time, the biodiesel production still reached a plateau of 67% conversion due to glycerol accumulation, which led to an increase in the mass transfer resistance. The biodiesel conversion was enhanced to 85% by carrying out the transesterification in a series of three packed-bed reactors integrated with glycerol removal devices. In the first column (H = 67 cm, I.D = 1.5 cm), triglyceride was converted to fatty acid methyl esters (FAME), glycerol, as well as a considerable amount of intermediate products, while the second (H = 67 cm, I.D = 2.0 cm) and third columns (H = 67 cm, I.D = 2.5 cm) continuously converted intermediate products to FAME with the supply of methanol and without the accumulation of glycerol. The PBR series system was able to continuously produce biodiesel at the yield of 4413 kg kg−1 celite-alkyl-lipase, without deactivation of the biocatalyst.