Masaru Sakata

Hydrolysis of soybean oil by lipase with a bioreactor having two different membranes

Abstract A membrane bioreactor with 25 sets of two different membranes, one hydrophilic and the other hydrophobic microporous, was used for the hydrolysis of soybean oil by lipase from Candida cylindracea . In the bioreactor, oil, water and enzyme liquid were separately fed into each of 3 clearances between the two membranes. Oil diffused through the hydrophobic membrane and water diffused through the hydrophilic membrane came into contact with the lipase, and hydrolysis subsequently took place. Fatty acid and glycerine produced by the enzymatic reaction diffused through each membrane into the oil and water sides respectively, so that these products were separated from each other. The enzyme was also separated from the products. In this membrane bioreactor, both reaction and separation occurred. Semi-continuous reaction of soybean oil with one cycle of 48 h was carried out for 18 d, at 45°C. Satisfactory performance of the bioreactor, such as a high hydrolysis percentage (92-88%) and enzyme stability over a long-term period was shown. Enzyme stability was found to depend on produced glycerine, as observed by Yamane et al. , and the rate of the hydrolysis reaction was controlled by that of the diffusion of fatty acid through the hydrophobic membrane.

Hydrolysis of palm stearin oil by a thermostable lipase in a draft tube-type reactor

Abstract Palm stearin oil, which has a high melting point and is generally used as the commercial raw material in oil chemistries, was hydrolyzed by a thermostable lipase produced from Pseudomonas sp. The initial reaction rate of oil hydrolysis was controlled by the interfacial area of the water/oil emulsion ( W O emulsion) where water was emulsified in oil, and it was represented by the Michaelis-Menten equation in which the interfacial area was substituted for the substrate concentration. A new bioreactor of a draft tube type which has the capability of functioning as an efficient continuous reactor for the separation of oil and water and the recovery of the enzyme was developed. By using the single-stage reactor, the hydrolysis ratio of palm stearin oil was maintained at 80% up to 230 h of operation, and percentage recovery of the enzyme was 98.8%. A countercurrent multistage reactor (three-stage reactor) was developed with the aim of improving the hydrolysis ratio. In the continuous hydrolysis of palm stearin oil using this reactor, the retention time of which was 36 h at each reactor, a high percentage hydrolysis of 95% and an incresed glycerin concentration of up to 30% were observed.

Preparation of Bacterial Adsorption Polymer and Its Application to Biosensors

Polymer particles immobilizing poly(N-benzyl-4-vinylpyridinium bromide) on their surfaces were prepared via reaction of a base polymer containing chloromethyl groups with poly(vinylpyridine), followed by quaternization with benzyl bromide. The polymer particles exhibited high adsorptive activity for microorganisms. A BOD sensor was prepared by a combination of a column packed with the polymer particles carrying activated sludge with an oxygen electrode. BOD values obtained using the BOD sensor agreed with those determined by the standard method.