Decolorization of Textile Effluent by Immobilized Aspergillus terreus

Synthetic dyes are widely used in a number of industrial processes, such as textile industries, paper printing, and photography. Dyes usually have synthetic origins and complex aromatic molecular structures. 

Dye wastewaters discharged from textile dyestuff industries have to be treated due to their impact on water bodies, and growing public concern over their toxicity and carcinogenicity in particular.Several strategies are currently available to remove color from the industrial effluent. These include physical processes such as membrane technologies, chemical processes such as ozonation,physicochemical methods, adsorption, chemical precipitation, flocculation,photolysis, and ion pair extraction and biological processes such as biodegradation and bioadsorption. The available m ethods require considerable start-up costs and cannot meet increasingly stringent effluent colour standards. Many different and complicated molecular structures of dyes make dye wastewaters difficult to be treated by conventional biological and physico-chemical processes. Therefore, innovative treatment methods need to be investigated.

Use of immobilized microbial cells in the field of wastewater treatment has been found to be useful because of the advantages which include long retention time of biomass in the system, ease of use in a continuous reactor and their ability for scale up. Search for alternative carrier for immobilization had shown the loofa sponge (Luffa cylindrica) as a suitable matrix for immobilization of various microorganisms like Candida brassica, Aspergillus niger and Lactococcus lactis. In the present investigations textile effluent from a local silk mill was obtained and its decolorization studied using immobilized Aspergillus terreus. Three different matrices for immobilization of Aspergillus terreus were tried namely, loofa sponge (Luffa cylindrica), coconut fibre and groundnut shells.