| Abstract
| - The removal of a carcinogenic dye rhodamine B (C. I. 45170) from wastewater by biomass of different mouldsand yeasts is described. Among all of the fungal species tested, the biomass of Rhizopus oryzae MTCC 262 is foundto be the most effective. Dye adsorption reaches maximum with the biomass harvested from the early stationary phaseof growth. The optimum temperature and pH for adsorption are observed to be 40 °C and 7.0, respectively. Theadsorption rate is very fast initially and attains equilibrium after 5 h. The adsorption isotherm follows the Langmuirisotherm model satisfactorily within the studied dye concentration range. Of the different metabolic inhibitors tested,2,4-ditrophenol (DNP) and N,N‘-dicyclohexylcarbodiimide (DCCD) decrease dye adsorption by ∼30% suggestingthe role of energy metabolism in the process. Spectrophotometric study indicates that the removal of rhodamine Bby R. oryzae biomass involves an adsorption process. Scanning (SEM) and transmission (TEM) electron microscopicinvestigations have been carried out to understand the probable mechanism of the dye−biomass interaction.
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