Title : Plasma surface activation of fibers for immobilization of enzymes on conductive and non-conductive textiles: Application to various processes
Porous textiles are flexible fibrous materials having high porosity (80-99%) and providing low pressure drop, a high surface-to-volume ratio for enzyme immobilization and allowing easy diffusion of reactant mixture (substrate and products). Monitoring of fiber diameter and pore size is possible using different techniques and the choice of chemical nature of the fiber is important to resist processes and to immobilize enzymes. Most enzyme immobilization methods are still facing challenges in terms of health hazards and high environmental impact. Thus, it is important to find eco-friendly approaches to achieve efficient enzyme immobilization with optimal bioactivity. Plasma treatments are eco-friendly processes which can be used to activate durable PET –polyethylene terephthalate or conductive carbon fiber nonwovens for appropriate enzyme immobilization at fiber surfaces. Not all plasma treatments using dielectric barrier discharge can be used to activate conductive carbon fiber surfaces.
Results of immobilization of ?-galactosidase and glucose oxidase (GOx) on PET and/or conductive carbon fibers will be presented.
In the first part, the effect of 3 different surface plasma treatments on the immobilization of β-galactosidase on a fibrous PET nonwoven membrane by gel-film entrapment and direct sorption methods will be described. β-galactosidase is an important enzyme biocatalyst used in food industry for the hydrolysis of lactose necessary for lactose-intolerant people. In addition, this enzyme catalyzes the formation of galacto-oligosaccharides, which are prebiotic additives for the so-called “healthy foods”. With the optimized sorption method using N2/O2 CRP plasma, no decrease in enzyme activity was detected, and the immobilized enzyme could be used over more than 15 cycles.
This study provides a novel method for enzyme immobilization under mild and controllable conditions, which can be interesting for use in food processing
In the second part, the effect of plasma treatments on GOx enzyme immobilization on electrically conductive supports will be described. Immobilization which allows enzyme bioactivity and stability improvement, for use and re-use in different applications, is important. Carbon-based textiles, are robust materials to be used as alternative for expensive rigid metals, since they possess good electrical conductivity and good resistance to corrosion in different media. They are however hydrophobic and their surface has to be activated using appropriate plasma dielectric barrier discharge. The results obtained showed that specific Cold Remote Plasma, was efficient in functionalizing the surface of carbon felts and PEDOT:PSS coated felts. This increased carbon surface energies facilitated the immobilization of GOx by physical adsorption with maintained bioactivity and improved reusability and interesting bio-electrochemical response. Finally, the obtained bio-functionalized carbon textiles were primarily evaluated for use in sustainable applications for wastewater treatment such as Bio-Fenton (BF) and enzymatic Bio-Electro-Fenton (BEF).