| Lysophosphatidylcholine (LPC), an excellent emulsifier with specific chemical structure, is obtained from the phosphatidylcholine (PC) by removal one acyl group and has unique physiological functions. This work reported the experimental data of alcoholysis of phosphatidylcholine (PC) using two commercial lipases (Novozym 435 and Lipozyme RM IM) in organic solvent (n-hexane). The experimental results showed the glycerophosphorylcholine (GPC) formed during the process. During the process of the alcoholysis of PC, the major reaction was the alcololysis of PC, however the side reaction, alcoholysis of LPC, always occurred. The type of lipase and alcohol could affect the balance of alcoholysis of PC and LPC.For alcoholysis catalyzed by Novozym 435, the reactive activity of alcoholysis of PC of these alcohols wereα-propelene glycol≈ethanediol > 1-butanol > ethanol > glycerol, the reactive activity of alcoholysis of LPC of these alcohols wereα-propelene glycol > ethanediol > 1-butanol≈glycerol > ethanol. For alcoholysis catalyzed by Lipozyme RM IM, the reactive activity of alcoholysis of PC of these alcohols were ethanediol >α-propelene glycol > glycerol > ethanol > 1-butanol, the reactive activity of alcoholysis of LPC of these alcohols were ethanediol > glycerol >α-propelene glycol > ethanol > 1-butanol.The effect of factors, such as temperature, enzyme dosage, solvent ratio (PC: n-hexane, m/v), substrate ratio (phospholipid: alcohol hydroxyl, mol/mol), on catalyzed alcoholysis reaction of phosphatidylcholine catalyzed by Novozym 435 were discussed. Based on single factor experiments, and the optimum conditions obtained through response surface method were temperature 60℃, enzyme dosage 10% (in mass of PC), solvent ratio 1:5 (PC: n-hexane, m/v), substrate ratio 1:2 (lecithin: hydroxyl of alcohol, mol/mol). The content of lysophosphatidylcholine in the crude product was 63.6%, LPC conversion was 93.5% under these conditions.The effect of temperature, enzyme dosage, solvent ratio (PC:n-hexane, m/v), substrate ratio (phospholipid: hydroxyl of alcohol, mol/mol) on alcoholysis of phosphatidylcholine catalyzed by Lipozyme RM IM were discussed. Based on single factor experiments, the possible optimum conditions obtained were temperature 55℃, enzyme dosage 15% (by mass of PC), solvent ratio 1:5 (PC: n-hexane, m/v), substrate ratio 1:3 (lecithin: hydroxyl of alcohol, mol/mol), time 24h. The crude LPC product, obtained from alcoholysis of PC andα-propelene glycol catalyzed by Novozym 435 under the optimum conditions, were extracted with n-hexane and the hexane insoluble fraction was re-extracted with ethanol, and LPC content of the purified product obtained by desolventization of the ethanol-soluble fraction was about 89%. The crude LPC product, were extracted with A/B mixture three times and the insoluble fraction was re-extracted with ethanol once, and LPC content of the purified product obtained by desolventization of the ethanol-soluble fraction was 92.7%. |
