Microhydrogels grafted onto macroporous (scaffolds) for bacterial immobilization: new alternatives for biocatalysis process.

FLAVIA QUIROGA; MARIANO GRASSELLI; JORGE A. TRELLES

Rosario (Argentina)

Congreso; V Congreso Argentino de Microbiología General; 2008

Sociedad Argentina de Microbiología General

The enzyme biocatalysis provides several advantages over traditional chemical routes, such as regio and stereoselectivity and environmentally clean production process. Moreover, microbial whole cells can be directly used as biocatalysts, what provides a simpler and cheaper methodology since enzyme isolation and purification are avoided. Very few reports have so far dealt with the use of immobilized microorganisms and most of them involved entrapment techniques that use materials with poor mechanical strength and durability (agar, agarose, alginate, chitosane) or toxicity to microorganisms (polyacrylamide, polyurethane). Therefore, the search of alternative techniques such as adsorption may provide new materials for whole cells supports. In many surface modification methods that promote or reduced bacterial interactions, radiation induced graft polymerization (RIGP) has an advantage in that enables the introduction of graft-chain-containing interfaces bearing functional groups into various polymeric backbones, providing the possibility of use materials with better mechanical features.  It is well known that bacteria cells have predominantly negative charges on their surfaces at neutral pH, therefore they can be efficiently adsorbed on a polymeric material carrying cationic groups. The aim of this work was the development of polymeric supports with new properties for whole cell inmobilization. A novel brush-type copolymeric interface was prepared onto macroporous sheets. As a result, a strategy for tailoring new supports for microbial cell immobilization has been explored. The prepared scaffolds were examined for their immobilization ability by contacting with cells suspensions in batch mode of a Gram-negative and Gram-positive bacteria strain. A high biocatalityc activity was observed in all the immobilization systems, with values that outperformed previously reports with E. Coli immobilized in a macroporous support grafted with pGMA modified by EDA. The results reflect the bacterial viability and retention capacity on the new polymeric support, with an increase of the biocatalytic activity, providing a new system for the development of immobilized biocatalyst.