Evaluation of enzyme carriers as biocatalysts for the conversion of emulsified rhamnolipids

Abstract

Different carriers were evaluated for α-l-rhamnosidase immobilization with respect to activity yield, activity loading and operational stability for the conversion of emulsified di-rhamnolipid to mono-rhamnolipid and l-rhamnose. The highest specific carrier activity of 88 U g⁻¹ with activity yield of 36% was obtained with micro non-porous carriers. Carrier activities of porous-type carriers were much lower due to strong substrate diffusional limitations. Furthermore, the effect of protein and activating-reagent concentration on immobilized enzyme activities on micro non-porous carriers was investigated by a response surface methodology. Immobilized enzyme activities decreased gradually with protein loading whereas the activating-reagent concentration hardly affected them.

Keywords::

• Rhamnolipids
• micro-carriers
• Naringinase
• immobilization
• α-l-rhamnosidase

Acknowledgements

We would like to thank the University of Karlsruhe for the financial support of this project in the frame of the Landesgraduiertenförderungsgesetz. We also thank Professsor Esther Oliveros of the Université Paul Sabatier, France, for her input when interpreting the response surfaces and also Xiaotian Ma for his practical input.