Different matrices viz. agar, alginate and polyacrylamide were examined for the immobilization of whole cells ofRalstonia
pickettii. The enzyme activity of whole cells immobilized in agar beads was very low. Alginate beads had the inherent disadvantage
of dissolving in phosphate based media and even glutaraldehyde treatment did not have any significant effect. A Tris – HCl system
was found to be the best for alginate based immobilization of whole cells fromR. pickettiiand 4% alginate beads gave an optimal
lipase activity of 14 U:ml per min. When different concentrations of polyacrylamide were tried for immobilization ofR. pickettii
whole cells, 15% polyacrylamide blocks showed a retention activity of 66% (25 U:ml per min) when compared to that of the free
cells (40 U:ml per min). Bis-acrylamide concentration of 0.15 g:10 ml of buffer was ideal and the optimum whole cell
concentration for polyacrylamide immobilization was 2.0 g:l of saline. Optimal immobilized whole cell concentration (polyacrylamide blocks) for lipase production was 20% and polyacrylamide blocks were reused three times effectively for lipase production.
Of the three matrices examined for the immobilization of whole cells fromR. pickettii, polyacrylamide gave the best performance.
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