Immobilization Of Lipase From Pseudomonas Fluorescens And Its Application In The Production Of Biodiesel

Sodium alginate-gelatin microcapsule stems from the Ca-alginate bead. It not only possesses the advantages of Ca-alginate bead, such as broad source, inexpensive cost, gentle immobilization conditions, easy operation, good biocompatibility, as well as less resistance to the substrates, but also provides more space for immobilized materials. Therefore, the sodium alginate-gelatin microcapsule is a promising immobilization carrier.During the preparation of sodium alginate-gelatin microcapsule, the effects of concentrations of sodium alginate(SA)and gelatin(GT)on the diameter and compression intensity of the microcapsule were examined, the diffusion coefficients of substrate from the solution into the microcapsule were measured with of glucose and bovine serum albumin fraction(BSA), according to the established mathematical model. The results showed that with the increasing of sodium alginate concentration, the diameter and compression intensity of the microcapsule became bigger. The optimum operation conditions were: the concentration of calcium chloridea 10%, drop rate 180 droplets/min, dipped in calcium chloridea 30min, under which conditions, the effective diffusion parameters of glucose and BSA measured were 4.63×10-5 cm2/min and 1.01×10-7 cm2/min, respectively.By following the above method, lipase from Pseudomonas fluorescens was immobilized. And the effects of immobilization conditions and immobilized enzyme stability against temperature and pH were studied. The results indicated that the optimum immobilized operation conditions were: lipase/sodium alginate ratio 300 IU, the diameter of the pinhead 6(0.5 mm), temperature 55℃and pH 8.0. Metalions and short-chain enathol had an insignificant effect on the immobilized enzyme.Then, the immobilized lipase was used to catalyze the transesterification reaction of soybean oil with methanol to produce biodiesel. The effects of enzyme amount, reaction temperature, adding ways of methanol, molar ratio of substrate on esterification were examined in details. The opitimal conditions of the methanolysis were: enzyme 25% of oil weight, methanol/oil molar ratio 4:1, reacting at 40℃for 35 h, and under which condition, the maximum metyl esters yield was over 82%.