Removal of methylene blue dye from aqueous solution using biomass of Cunninghamella echinulata UCP 1297 as superbiosorbent / Remoção do corante azul de metileno de solução aquosa usando biomassa de Cunninghamella echinulata UCP 1297 como superbiossorvente

Abstract

Nowadays, water pollution caused by dye contaminants has become a severe global issue and aroused tremendous attention, since it is estimated that more than 100 thousand types of commercial organic dyes have been produced. Meanwhile, huge amounts of dyes have been discharged into natural environment during the production process, which causes serious environmental problems. Hence, it is quite urgent to remove the dyestuffs from water, and several methods have been devoted to resolving this issue, including biosorption processes. In this context, this study aimed the decolorization of methylene blue using biomass of Mucoralean fungi Cunninghamella echinulata UCP 1297, as alternative biosorbent. The fungus C. echinulata was initially cultivated in low-cost medium containing 1% corn steep liquor and 5% mature Pacovan banana (Musa sapientum) peel flour, at pH 6, 28ºC and 150 rpm, during 96 h. Fungal biomass obtained after filtration and centrifugation of cultures was subjected to lyophilization. The biosorbent (lyophilized biomass was sieved to obtain particles of size less than 1.0 mm, which were used for decolorization of methylene blue from aqueous solution at concentration of 5 mg/L. Experiments were carried out for 24 and 48h at 28ºC, using a 23 full-factorial design (FFD) to evaluate the influence of agitation, pH and amount of biosorbent. Discoloration was determined by measuring absorbance at 660 nm in UV-Visible spectrophotometer. According to the results, fungal biomass proved to be an excellent biosorbent of methylene blue, showing the highest percentage of removal (95.407%) and (96.427%) were observed in the condition 8 of the FFD, with the maximum levels of the evaluated variables (200 rpm of agitation, pH 9 and 90 mg of biomass). However, in the condition 4 similar variables, except to biomass (200 rpm of agitation, pH 9 and 10 mg of biomass) showed a lower methylene blue removal as 0.413 and 10.249%, respectively to 24 and 48h of incubation. The results indicated that the amount of Cunninghamella echinulata UCP 1297 biomass influenced the decolorization bioprocess of the methylene blue azo dye, proving to be a superbiosorbent. Thus, this study confirmed the suitability of fungal biomass for dye removal process and the cost-effectiveness of it uses due to inexpensive medium for production using agro-industrial residues.