Azo-Dye Decoloration by Pseudomonas sp. Immobilized in Sol-Gel Silica Matrices

TUTTOLOMONDO MARÍA VICTORIA; ALVAREZ GISELA; MANFREDI, GASTÓN; DESIMONE MARTÍN; DÍAZ LUIS

Mar del Plata

Congreso; Congreso Internacional de Ciencia y Tecnología Ambiental; 2012

Among many pollutants, textile industry effluents are the major source of environmental pollution. Synthetic dyes are widely used in the textile, pharmaceutical, cosmetic, and food industries. These effluents are a serious concern because of their adverse effects on many organisms and ecosystem as a whole. Even small concentrations of dye are highly visible and can be toxic to aquatic organisms. Azo dyes are the largest and most versatile class of dye but due to their chemical properties, they are not easily degradable under natural conditions and thus, are not thoroughly removed from water by conventional wastewater treatment systems[1,2]. In this work we propose the use of sol-gel silica matrices obtained from sodium silicate to immobilize Pseudomonas sp., an azo-dye decolorizing bacteria. The model dyes chosen for the experiments were: Remazol Black (RB); Methyl Orange (MO) and Benzyl Orange (BO). The advantages of bacteria immobilization are the possibility to recycle the beads, protect bacteria and reduce their presence in the resulting fluid. Bacteria were cultured aerobically at 35 ºC in aqueous solutions of different concentrations of azo-dyes. Azo-dye remnants were measured directly by absorption at their maximum lambda [3,4]. Immobilized P. sp. was resistant to 2% of the tested dyes. Furthermore, recent studies allow us estimate the reutilization and half-life of the immobilized bacteria. The degradation products and the ability of the sol-gel matrix to bind them is also under study.