The influence of immobilization of Pseudomonas sp 2 on optical detection of polychlorinated biphenyls

The cells Pseudomonas sp. 2 were immobilized on porous glass surface (S), encapsulated into alginate beads (A), encapsulated into alginate beads coated with a silica layer (AC) and entrapped into silica gel (C). The silica layer thickness of 2.5 mum was prepared from prepolymerized tetramethoxysilane by dipping of the alginate beads. The production of stable yellow intermediates of biodegradation of PCBs, congeners with three chlorine atoms, was used for the detection of commercial mixture of PCBs, Delor 103. In the initial stage of biodegradation of Delor 103, the highest and the most rapid increase of concentration of yellow color was observed in the case of biodegradation with AC but the selectivity of the detection method was decreased by the simultaneous production of orange compounds. The necessary conditions for production of orange intermediates were concentration of biphenyl or PCBs with biphenyl 5 g/l together with 2-6 vol.% of methanol. Trihydroxyphenyl pyridine, phenyl pyridine, dimethythydrazide of benzoic acid, pyridine carboxylic acid and trimethylindane were identified in the lyophilized solution of the orange compounds. The metabolic pathways of the creation of orange compounds are unknown and for that reason, utilization of these metabolites for optical detection of PCBs needs further research. (C) 2002 Elsevier Science B.V. All rights reserved.