Abstract: Due to the existence of new methodologies that have reduced the production costs of microbiological chitosan, this paper puts forward the use of agro-industrial residues in order to produce microbiological chitosan and to apply chitosan as an innovative resource for removing acid orange 7 (AO7) from wastewaters. The best culture conditions were selected by a full 24 factorial design, and the removal of the dye was optimized by a 23 central composite rotational design. The results showed that corn steep liquor (CSL) is an agro-industrial residue that can be advantageously used to produce microbiological chitosan with yields up to 7.8 g/kg of substrate. FT-IR spectra of the product showed typical peak distributions like those of standard chitosan which confirmed the extracted product was chitosan-like. The efficiency of removing low concentrations of AO7 by using microbiological chitosan in distilled water (up to 89.96%) and tap water (up to 80.60%) was significantly higher than the efficiency of the control (chitosan obtained from crustaceans), suggesting that this biopolymer is a better economic alternative for discoloring wastewater where a low concentration of the dye is considered toxic. The high percentage recovery of AO7 from the microbiological chitosan particles used favors this biopolymer as a possible bleaching agent which may be reusable.
Keywords: microbiological chitosan; acid orange 7 (AO7); central composite rotational design; agro-industrial residues; Syncephalastrum racemosum; corn steep liquor; coagulation-flocculation
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Batista, A.C.L.; Silva, M.C.F.; Batista, J.B.; Nascimento, A.E.; Campos-Takaki, G.M. Eco-Friendly Chitosan Production by Syncephalastrum racemosum and Application to the Removal of Acid Orange 7 (AO7) from Wastewaters. Molecules 2013, 18, 7646-7660.
Batista ACL, Silva MCF, Batista JB, Nascimento AE, Campos-Takaki GM. Eco-Friendly Chitosan Production by Syncephalastrum racemosum and Application to the Removal of Acid Orange 7 (AO7) from Wastewaters. Molecules. 2013; 18(7):7646-7660.
Batista, Anabelle C.L.; Silva, Marta C.F.; Batista, Jefferson B.; Nascimento, Aline E.; Campos-Takaki, Galba M. 2013. "Eco-Friendly Chitosan Production by Syncephalastrum racemosum and Application to the Removal of Acid Orange 7 (AO7) from Wastewaters." Molecules 18, no. 7: 7646-7660.