Screening of whole-cell immobilization procedures for the Delta super(1)-dehydrogenation of steroids in organic medium

• Published in: Enzyme and microbial technology Vol. 14; no. 8; pp. 619 - 624
• Main Authors: Pinheiro, H M, Cabral, JMS
• Format: Journal Article
• Language: English
• Published: 01.01.1992
• Subjects: Arthrobacter simplex
• ISSN: 0141-0229

Different whole-cell immobilization methods and conditions were tested for the Delta super(1)-dehydrogenation of 6- alpha -methyl-hydrocortisone-21-acetate with Arthrobacter simplex) cells, in n-decane-1-ol and chloroform. Among the entrapment methods, polyurethane foams gave the best productivity of n-decane-1-ol, but could not be used in chloroform. Partition and diffusional barriers appeared to be the factors limiting productivity in entrapped-cell systems. The coentrapment of enzyme-stabilizing (glycerol, sucrose, sodium sulfate, monosodium glutamate) or hydrophobic additives did not significantly improve dehydrogenation rates in chloroform, although in some cases higher activities resulted in n-decane-1-ol. Dehydration of Kappa -carrageenan-immobilized cells lowered the productivity in both solvents. The use of cell adsorption methods on silica-based carriers produced biocatalysts that in some cases were more active in chloroform than the entrapped cells.