Satoshi Negishi

Utilization of powdered pig bone as a support for immobilization of lipase

Abstract Pig bone was examined for its suitability as a support material for lipase immobilization. It was observed that pig bone (PB) particles dispersed readily in both polar and nonpolar solvents, and lipase was easily adsorbed. In particular lipase adsorbed on olive oil-soaked pig bone (OPB) particles exhibited a higher hydrolytic activity than that in lipase adsorbed on a selection of other representative supports, regardless of removing the presoaked olive oil from the particles after immobilization of lipase. The optimum pH and temperature for hydrolytic activity of OPB-adsorbed lipase were the same as those for free lipase, although thermal resistance was increased by immobilization. When OPB-adsorbed lipase was used for repeated batch reactions of olive oil hydrolysis, an activity of more than 80% of the initial activity of each run could he retained after 46 h reaction. The results suggest that PB is an excellent support material.

Effect of substrate presoaking treatment of support materials on the activity of immobilized glucoamylase

The activity of immobilized glucoamylase was remarkably increased by presoaking treatment of the supports in soluble starch solution. Pig bone (PB) particles-100 showed the largest substrate presoaking effect among some representative support materials, increasing the activity of immobilized glucoamylase by 10 times. The improvement in the activity was due to the increase in the specific activity of immobilized proteins. In order to get sufficient substrate presoaking effect, a rapid crosslinking treatment of the enzyme and the substrate-presoaked support was required. The glucoamylase immobilized on PB sheet was very stable and gave a high starch hydrolysis of DE95 (dextrose equivalent) for about 1 month in continuous process.

Substrate presoaking effect on immobilization of protease on pig bone particles.

Abstract When pig bone (PB) particles and other support materials were presoaked in casein solution and crosslinked with glutaraldehyde, the activity of immobilized protease, was two or more times greater than those of the proteases immobilized on non-treated supports. Chitopearl was an exception. The highest activity, 25000 U/g-support, was obtained with the presoaked PB particles. The effect of presoaking the supports in the substrate solution on the immobilized protease was also observed with other protein substrates. The effect of the presoaking treatment increased with an increase in the molecular weight of the protein. The increase in the activity of the immobilized enzyme was due to increases in both the amount of adsorbed protease and specific activity. Furthermore, the stability of protease immobilized on PB was remarkably improved by transforming the PB particles into a sheet.