title: Enrichment of microbial cultures able to degrade 1,3-dichloro-2-propanol: a comparison between batch and continuous methods.
abstract: Microbial cultures able to degrade xenobiotic compounds are the key element for biological treatment of waste effluents and are obtained from enrichment processes. In this study, two common enrichment methods, suspension batch and immobilized continuous, were compared. The main selection factor was the presence of 1,3-dichloro-2-propanol (1,3-DCP) as the single carbon source. Both methods have successfully enriched microbial consortia able to degrade 1,3-DCP. When tested in batch culture, the degradation rates of 1,3-DCP by the two consortia were different, with the consortia obtained by batch enrichment presenting slightly higher rates. A preliminary morphological and biochemical analysis of the predominant colonial types present in each degrading consortia revealed the presence of different constituting strains. Three bacterial isolates capable of degrading 1,3-DCP as single strains were obtained from the batch enrichments. These strains were classified by 16S rRNA analysis as belonging to the Rhizobiaceae group. Degradation rates of 1,3-DCP were lower when single species were used, reaching 45 mg 1(-1) d(-1), as compared to 74 mg 1(-1) d(-1) of the consortia enriched on the batch method. Mutualistic interactions may explain the better performance of the enriched consortia.
authors.affiliation: Escola Superior de Biotecnologia, R. Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal.
authors.forename: Filipe
authors.initials: F
authors.lastname: Bastos
authors.forename: José
authors.initials: J
authors.lastname: Bessa
authors.forename: Catarina C
authors.initials: CC
authors.lastname: Pacheco
authors.forename: Paolo
authors.initials: P
authors.lastname: De Marco
authors.forename: Paula M L
authors.initials: PM
authors.lastname: Castro
authors.forename: Manuel
authors.initials: M
authors.lastname: Silva
authors.forename: Ruben Ferreira
authors.initials: RF
authors.lastname: Jorge
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism; D003470:Culture Media; D004787:Environmental Pollution; D009153:Mutagens / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012230:Rhizobiaceae / Q000378:metabolism; D012988:Soil Microbiology; D000517:alpha-Chlorohydrin / Q000031:analogs & derivatives / Q000378:metabolism*
chemical_list: D002712:Chlorides; D003470:Culture Media; D009153:Mutagens; D012336:RNA, Ribosomal, 16S; C033489:1,3-dichloro-2-propanol; D000517:alpha-Chlorohydrin