Selection and characterization of aerobic bacteria capable of degrading commercial mixtures of low-ethoxylated nonylphenols.
OBJECTIVE
Isolation and characterization of new bacterial strains capable of degrading nonylphenol ethoxylates (NPnEO) with a low ethoxylation degree, which are particularly recalcitrant to biodegradation.


RESULTS
Seven aerobic bacterial strains were isolated from activated sludges derived from an Italian plant receiving NPnEO-contaminated wastewaters after enrichment with a low-ethoxylated NPnEO mixture. On the basis of 16S rDNA sequence, the strains were positioned into five genera: Ochrobactrum, Castellaniella, Variovorax, Pseudomonas and Psychrobacter. Their degradation capabilities have been evaluated on two commercial mixtures, i.e. Igepal CO-210 and Igepal CO-520, the former rich in low ethoxylated congeners and the latter containing a broader spectrum of NPnEO, and on 4-n-nonylphenol (NP). The strains degraded Igepal CO-210, Igepal CO-520 and 4-n-NP all applied at the initial concentration of 100 mg l(-1), by 35-75%, 35-90% and 15-25%, respectively, after 25 days of incubation.


CONCLUSIONS
Some of the isolated strains, in particular the Pseudomonas strains BCb12/1 and BCb12/3, showed interesting degradation capabilities towards low ethoxylated NPnEO congeners maintaining high cell vitality.


CONCLUSIONS
Increased knowledge of bacteria involved in NPnEO degradation and the possibility of using the isolated strains in tailored process for a tertiary biological treatment of effluents of wastewater treatment plants.
Di Gioia
D
D
DICASM, Faculty of Engineering, University of Bologna, viale Risorgimento 2, Bologna, Italy.
Michelles
A
A
Pierini
M
M
Bogialli
S
S
Fava
F
F
Barberio
C
C
D001420:Bacteria, Aerobic / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005026:Ethylene Glycols; D007220:Industrial Waste; D042041:Ochrobactrum / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism; D044096:Psychrobacter / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012722:Sewage; D013501:Surface-Active Agents; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical
D005026:Ethylene Glycols; D007220:Industrial Waste; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C021754:terics