Enhanced Lipase Immobilization Amount and Activity on Natural Bacteria Cellulose by Atmospheric Pressure Plasma Treatment

Enzyme immobilization is a splendid way in a majority of industrial processes. However, traditional technologies still remain some defects, like multiple steps, vigorous chemical reaction with carrier surface, etc. Plasma material surface modification is a novel and convenient way for enzyme immobilization on polymer materials. Up till now, very little has been reported for lipase immobilization on natural bacteria cellulose by using atmospheric pressure low temperature plasma. In this paper, an atmospheric pressure Dielectric Barrier Discharge (DBD) was introduced to modify lipase immobilization and activity on bacteria cellulose (BC) membrane. He plasma treatment and He with NH
3
·H
2
O plasma treatment presented opposite results, while He with NH
3
·H
2
O plasma treatment largely enhanced the lipase immobilization and activity, however, the former decreased on the contrary. Scanning Electron Microscope (SEM), pore size distribution, surface area, average pore size, water contact angle and ATR-FTIR measurements showed that the enhancement of lipase immobilization amount and activity on natural bacteria cellulose membrane He with NH
3
·H
2
O plasma treatment can be explained as follows: (1) Natural straight chain structure of bacteria cellulose was broken into granule-like glucose units (~50nm diameter); (2) These structure change affected pore size distribution on surface, which leaded to enlarged surface area and reduced average pore diameter; (3) At the same time, increased water contact angle leaded to less hydrophilic bacteria cellulose membrane, but much better for lipase immobilization and activation. Situation is inverse in the He plasma treatment group.