Biodegradation of phenol by using free and immobilized cells of Acinetobacter sp XA05 and Sphingomonas sp FG03

Strain XA05 and FG03 with high biodegradation activity of phenol were isolated from the activated sludge and phenol-contaminated soils in Northwest of China, respectively. DNA sequencing and homologous analysis of 16s rRNA gene identified that XA05 belonged to an Acinetobacter sp. and FG03 was closely related to the Sphingomonas sp. Strain XA05 and FG03 were mixed at the ratio of 1:1, and polyvinyl alcohol (PVA) was used as a gel matrix to immobilize mixed cells of two strains by repeated freezing and thawing. The removal efficiency of phenol by free and immobilized cells and factors affecting phenol degradation were investigated, the stability of the immobilized cells was also reported. Experimental values indicated that both free suspended and immobilized cells showed high phenol degradation efficiencies, higher than 95% within 35 h with an initial concentration of 800 mg/l phenol, and the immobilized cells showed better performance than that of the suspended cells. (C) 2008 Elsevier B.V. All rights reserved.