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Biotechnology and Applied Biochemistry (2000) 31, (179–183) (Printed in Great Britain)

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Immobilization of Pseudomonas cepacia lipase in a phyllosilicate sol–gel matrix: effectiveness as a biocatalyst

An-Fei Hsu¹, Thomas A. Foglia and Siyan Shen

U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, U.S.A.

Abbreviations used: PS-30, lipase from Pseudmonas cepacia; TMA, trimethylammonium chloride; CTMA, cetyltrimethyl ammonium chloride; PTMS, propyltrimethoxysilicate; TMOS, tetramethyl orthosilicate; GC, gas chromatography.

¹ To whom correspondence should be addressed.

A novel procedure is described for immobilizing a lipase from Pseudomonas cepacia (PS-30) within a phyllosilicate sol–gel matrix. The method is based on cross-linking a phyllosilicate clay with silicate polymers produced by the controlled hydrolysis of tetramethyl orthosilicate (TMOS). The activity of the phyllosilicate sol–gel-immobilized lipase was dependent upon the type of alkylammonium salt, inorganic catalyst and volume ratio of phyllosilicate clay to TMOS used. Lipase PS-30 immobilized in this way was more stable and had higher activity compared with the free lipase. Studies on the lipase-catalysed esterification of lauric acid with octan-1-ol in iso-octane showed that under controlled water activity conditions the phyllosilicate sol–gel-immobilized lipase had better activity compared with other supported lipase preparations. In addition, the phyllosilicate sol–gel-immobilized lipase was reusable for at least five esterification cycles without significant loss of activity.

Received 13 September 1999/10 January 2000; accepted 21 January 2000

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