Stabilization of microorganisms in nanocomposite hydrogels

CAPPA, V.; RIVERO, C.; SAMBETH, J.; LOZANO, M. E.; TRELLES, J.A.

Ciudad de Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Immobilization of microorganisms is a current topic in biotechnology and a promising production method for bioprocessEntrapment techniques are the most widely used for whole cell immobilization despite of their high operational stability, easy upstream separation and feasibility of scaling up the bioprocessHowever, in most cases the beads are mechanically unstable. The incorporation of nanocomposites in the matrix promotes the rigidity and stability of the biocatalystsIn this work, we used natural and synthetic polymers (agar, agarose, alginate and polyacrilamide) to immobilize by entrapment microorganisms. Calcium alginate was the best support for microorganism stabilization and different immobilization parameters as support concentration, bead size, crosslinking solution and exposure time were optimized. The optimal immobilization conditions were4%(w/v) alginate, 3mmbead size, 0,2 M SrCl2 as a crosslinking solution and 2 hs of exposure timeThis biocatalyst was able to catalyze 70% of ribose 1-phospate in 6 h of reaction using thymidine as started subtract. Finally, this biocatalyst showed high operational and storage stability and retained full activity for more than 120 hs of use. Additionally, we evaluated the effect of bentonite, a natural nanocomposite, to improve bioprocess parameters as swelling, cell retention, compression strength and stability.