Immobilized enzymes pancreatic lipase

Amongst the lipases, the pig pancreatic lipase (PPL), the yeast lipase from Candida cylindracea (rugosa) (CCL), and the bacteria lipases from Pseudomonas fluorescens (cepecia) (PEL) and other unclassified Pseudomonas species (PSL) have been most widely used. The experimental methods are very straightforward and little different in their execution from conventional chemical reactions. Hydrolysis reactions are conducted on the soluble lipase in buffered aqueous solutions, commonly in the presence of an organic cosolvent. In organic media the enzyme is added as a powder or in an immobilized form and the resulting suspension stirred or (better) shaken at approximately 40 °C. The enzyme is removed by filtration. 

Because free-enzyme porcine pancreatic lipase had much lower activity in SCCO2 than in organic solvents, the authors decided instead to test immobilized lipases. Macroporous resin-supported lipase from M. miehei had fair activity but poor enantioselectivity. Porcine pancreatic lipase immobilized on supports had the greatest activity if the support was highly hydrophilic Sephadex G-25 and Bio-gel P6 were selected. Enantioselectivity was 83% for the (5)-gycidyl butyrate at 25-30% conversion, comparable to results in organic solvents. Several chiral alcohols were studied by Cernia et al. (80) as substrates for kinetic resolution by esterification catalyzed by silica-supported lipase from Pseudomonas sp. [Eq. (5)] ... 

Enzymes can be used to selectively hydrolyze only one of two ester groups in a molecule. An esterase from Pseudomonas putida was used to hydrolyze dimethyl adipate to more that 99% half ester.198 Pig liver esterase was used to hydrolyze dialkyl phthalates to the monoesters in 84-93% yields in 1-13 h.199 A porcine pancreatic lipase was used to hydrolyze linear diol diacetates to the monoacetates in 79-95% yields.200 Esters have been prepared from 12-hydroxystearic acid and C8-C18 alcohols in 82-90% yields without esterification of the 12-hydroxy group, by using an immobilized lipase from Rhizomucor miehei.201 Ricinoleic acid, which differs only by having a cis 9 double bond, formed oligomers with an immobilized lipase from C. rugosa.202 These were much less colored than the ones made by the commercial process, which is done at 200 C. 

On the other hand, immobilized enzymes seem to perform much better in SCFs. Thus in the esterification of glycidol with butyric acid on porcine pancreatic lipase, the immobilized form of the enzyme (with 20-25% hydration) gives three times higher rates than the optimized free enzyme containing 10% water (Martins et al., 1994). 

In the field of organic synthesis, it was reported that the catalytic hydrolysis of umbelliferone esters (7-acetoxycoumarin) to 7-hydroxycoumarinby porcine pancreatic lipase covalently immobilized on microchannel reactors almost completed within 1 min, to be compared with 4 min in a normal batch reaction [86]. The same group demonstrated an improvement in the yield of trypsinmicrochannel reactor with a lower enzyme concentration but a 20-fold higher reaction rate than in a batch reactor [87]. 

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