Biodegradation of Phenol by Immobilized Aspergillus awamori Cells

1Department of Chemical Engineering, Vellore Institute of Technology, Vellore-632014 Tamil Nadu, India
2Department of Biotechnology, University of Food Technologies, BG-4002 Plovdiv, Bulgaria


SHYAM SUNDAR, P., D. K. DANIEL and A. I. KRASTANOV, 2005. Biodegradation of phenol by immobilized Aspergillus awamori cells. Bulg. J. Agric. Sci., 11: 725-735

In the present study, cells adapted to the phenolic environment were used for immobilization onto alginate beads. The experiments conducted with phenol as the sole source of carbon showed that the organism was capable of mineralizing phenol up to a concentration of 1000 ppm. After ascertaining the potential of the organism to degrade phenol, batch studies on the degradation of phenol were conducted with immobilized cells to analyze the effects of various parameters viz., initial phenol concentration, initial pH, carbon source concentration and bead size. The amount of degradation was in the range 49 - 83%, depending on the concentration of phenol. The amount of degradation was found to decrease with increase in the phenol concentration. After preliminary confirmation of the effects of these parameters, Taguchi's technique was applied to obtain an optimal setting of the parameters viz., initial phenol concentration, initial pH, carbon source concentration, bead size and time of contact. The results indicated that initial phenol concentration and time of contact were the control parameters and initial pH and bead size, were the signal parameters. Initial phenol concentrations, initial pH, time of contact and bead size were found to be the most significant parameters at levels 100 ppm, 5.5, 50 h and 3.05 mm respectively. The reusability studies of the immobilized beads indicated that there was no significant deterioration in the activity of the beads with subsequent usage up to four times.

Key words: Cell immobilization, Aspergillus awamori, Phenol biodegradation