Degradation of phenol by PAA-immobilized Candida tropicalis

• Published in: Enzyme and microbial technology 2002-09, Vol.31 (4), p.490-497
• Main Authors: Chen, Kuo-Cheng, Lin, Yun-Huin, Chen, Wen-Hsiang, Liu, Yi-Chun
• Format: Article
• Language: English
• Subjects: Biodegradation; Biodegradation of pollutants; Biological and medical sciences; Biotechnology; Candida tropicalis; Environment and pollution; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; PAA-immobilized cells; Phenol
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/S0141-0229(02)00148-5

Immobilized growing cells of Candida tropicalis were prepared by entrapment into polyacrylamide (PAA) gel beads. Continuous degradation was conducted with inlet phenol concentration ranging from 1000 up to 5000 mg l −1. It was found that inlet concentrations of 4000 and 5000 mg 1 −1 took less than 5 and 10 days, respectively, to achieve a phenol removal efficiency of over 95%. The maximum biodegradation rate of 7.68 g l −1 per day was reached at the inlet concentration of 5000 mg l −1. The formation of PAA gel beads was accomplished in aqueous phase associated with the gelling reaction of Ca-alginate. Effects of monomer concentration and crosslinkerlinker content on the diffusivity of phenol in gel beads were studied. The oxygen diffusivity in gel beads was estimated according to a well-known theoretical model using experimental data. It was found that the ratio of oxygen diffusivity in gel beads to that in water was around 30%. The immobilized-cell beads were used to degrade phenol in an air-lift bioreactor undergoing continuous operation at a constant hydraulic retention time of 15 h (dilution rate 0.067 h −1).