CGA로 제조된 미생물 담체 PVA-하이드로젤의 PAH 분해 연구

Abstract

We have evaluated PAH degradation by bacteria-immobilized, PVA-hydrogels made via CGA technique as well as degree of cell immobilization on the gels. Hydrogels were prepared with use of diverse cross-linking agents so as to better fit to the cell immobilization, which resulted in changes in pore structure and size as well as in some physical properties. L-ascorbic acid among glucose, methionine, citric acid and vitamins, imparted not only the most favorable physical properties and the greatest cell density but also the highest PAH degradation on its derivative gels. The higher number of aromatic rings lowered the degradation rates and efficiencies in a more or less proportional manner probably because the key degradation enzyme such as PAH-oxygenase would be less active due to more complicated enzymatic pathways with more rings. Direct cell-immobilization guaranteed higher biomass in the gels. The higher biomass ensured the higher degradation rate in general; the maximum cell density was 0.27 mg/g-gel with 92% efficiency and 0.013 mM/g-gel/day (for phenanthrene). Microscopic observation showed the smoother outer surfaces of the gels, confirming that there was biofilm developed, thus the gels applicable as environmental media.