An aerobic fixed-phase biofilm reactor system for the degradation of the low-molecular weight aromatic compounds occurring in the effluents of anaerobic digestors treating olive mill wastewaters.
An aerobic co-culture, prepared by combining Ralstonia sp. LD35 and Pseudomonas putida DSM1868, was recently found to be capable of extensively degrading many of the hydroxylated and/or methoxylated benzoic, phenylacetic and 3-phenyl-2-propenoic acids occurring in the olive mill wastewaters (OMWs). In the perspective of developing a biotechnological process for the degradation of low-molecular weight (MW) aromatic compounds occurring in the effluents of anaerobic digestors treating OMWs, the capability of this bacterial co-culture of biodegrading a synthetic mix of the above mentioned compounds and the aromatic compounds of an anaerobic OMW-treatment plant effluent in the physiological state of immobilised cells was investigated. Two aerobic fixed-bed biofilm reactors were developed by immobilising the co-culture cells on Manville silica beads and on polyurethane foam cubes. Both supports were found to give rise to a microbiologically stable and biologically active biofilm. The two biofilm reactors were found to be similarly capable of rapidly and completely biodegrading the components of a synthetic mix of nine monocyclic aromatic acids typically present in OMWs and the low-MW aromatic compounds occurring in the anaerobic effluent in batch conditions. However, in the same conditions, the silica bead-packed reactor was found to be more effective in the removal of high-MW phenolic compounds from the anaerobic effluent with respect to the polyurethane cube-packed reactor. These results are encouraging in the perspective of using the co-culture as immobilized cells for developing a continuous biotechnological process for the post-treatment of effluents with low-MW aromatic compounds produced by anaerobic digestors treating OMWs.
DICASM, Faculty of Engineering, University of Bologna, viale Risorgimento 2, I-40136 Bologna, Italy.
L
L
Bertin
M
M
Majone
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D
Di Gioia
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F
Fava
D000332:Aerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002733:Chlorophenols / Q000378:metabolism; D005285:Fermentation; D016946:Gram-Negative Aerobic Rods and Cocci / Q000378:metabolism; D006841:Hydrocarbons, Aromatic / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D016958:Pseudomonas putida / Q000378:metabolism; D014865:Waste Disposal, Fluid / Q000379:methods; D018505:Waste Management / Q000379:methods*
D002733:Chlorophenols; D006841:Hydrocarbons, Aromatic; C030683:2-chlorophenol