Immobilization of bacteria in microgel grafted onto macroporous polyethylene

JORGE A. TRELLES; FLAVIA QUIROGA; CLAUDIA BRITOS; EDUARDO E. SMOLKO; MARIANO GRASSELLI

Angra dos Reis

Simposio; 8th International Symposium on Ionizing Radiation and Polymers (IRaP); 2008

irAp

The development of the ?Green Chemistry? requires of new materials to replace the conventional organic chemistry by biological catalysts, to produce fine chemicals in an environmentally friendly manner. 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 microbial cells for nucleoside synthesis and most of then involved entrapment techniques.Recent advances in macromolecular biomaterial technology combine the effort of scientists in various fields to obtain polymers with well-defined structures and specific chemical, physicochemical, mechanical and biological properties. Due to the fact that microbial cells have predominantly negative charges on their surfaces, they can be efficiently adsorbed on a polymeric material carrying cationic groups.Polyethylene (PE) is a very stable polymer however can be activated by gamma radiation to induce grafting. Glycidyl methacrylate was used as monomer and different alcohols as solvent to induced simultaneous grafting onto macroporous PE. Different monomer concentration reaches proportional grafted polymer which is further chemically modified by ring-opening reaction onto the epoxy groups. The chemical reaction of ethylenediamine creates a cationic hydrogel with micron-size thickness onto the PE surface. The surface modification was reveal by the complexation of copper ions. After neutralization, the microhydrogel was tested for loading microorganisms. One Gram positive and one Gram negative bacteria were analysed. In all cases bacteria was immobilized onto the grafted material. All chemical and biochemical steps were following by FT-IR ATR spectroscopy. SEM and TEM microscopy clearly show the surface modification of PE and the inclusion of bacteria into the grafted microhydrogel. Immobilized bacterial viability was tested by the hydrolysis of uridine to uracile.