Abstract: Rhizopus oryzae cells were immobilized respectively with 4 different supports, including diatomite, polyurethane foam resin (PUF), alumina and sodium alginate, and the immobilized cells were used to catalyze methylation of soybean oil with methanol. The results showed that PUF was the most suitable immobilizing support for R. oryzae cells. When 0.6gPUF was added into 80mLculture medium, the obtained immobilized cells biocatalyst had optimal performance, in which immobilized dry weight of cells and lipase activity of the culture fluid were 0.5560g and 17.4U/mL, respectively. The yield of methyl esters (ME) from the methylation of soybean with methanol catalyzed by PUF immobilized cells could reach 94%when m(methanol):m(soybean oil) was 5:1 and methanol was added in 5 batches (12h for each batch). The whole-cell biocatalyst of PUF immobilized cells can be simply prepared and separated, and it is environment-friendly and reusable.

Key words: Rhizopus oryzae, immobilized cells, whole-cell biocatalyst, methylation