Decolorization of anthraquinone dye by Aspergillus ficuum in various physiological states.

Decolorization of reactive brilliant blue KN-R by Aspergillus ficuum was investigated on suspended spores, mycelial pellets, immobilized cells. It was found that Aspergillus ficuum could effectively decolorize reactive brilliant blue KN-R especially when grown as pelleted mycelia. Many factors affecting the decolorization process in nitrogen-limited media (NLM) were studied, including: initial pH, temperature, and mycelial age. Results showed that the media containing reactive brilliant blue KN-R at 50 mg/L could be decolorized by 96% of the initial color in 42 h, in most conditions tested, the dye degraded products assayed by UV-visible spectrophotometer and macroscopic observation showed that the decolorization of reactive brilliant blue KN-R by mycelial pellets includes two important processes: biodegradation and biosorption. Kinetic study revealed that reactive brilliant KN-R biodegradation by mycelial pellets and suspended spores conformed to first-order reaction model while reactive brilliant blue KN-R biodegradation by immobilized cell followed zero-order model. In addition, mycelial pellets was found to biodegrade KN-R more quickly than suspended spores and immobilized cell.

Bio-metabolic disposition of metanil yellow, orange II and their blend by caecal microflora of rats.

Caecal microflora were employed to study the degradation pattern, with time course of Metanil yellow and Orange II-two extensively used non-permitted food colours. Metanil yellow and Orange II showed the respective Degradation Index 50 (DI 50) values of 369 and 288 min. However, the blend of Metanil yellow and Orange II (1:1) resulted in the D1 50.value of 288 min. Metanil yellow, Orange II and their blend were resolved into respective metabolites in different solvent systems.