title: Functional consortia for cresol-degrading activated sludges: toxicity-to-extinction approach.
abstract: The conventional roll tube and plating techniques are typically time consuming and can culture in vitro only a small fraction of microbes in natural microflora. This study utilizes a novel, simple, and rapid method, the toxicity-to-extinction approach, to obtain the minimal functional consortium that can effectively degrade meta- (m-), para- (p-), and ortho- (o-) cresols. The original sludge had 16 major bands by denaturing gradient gel electrophoresis (DGGE). Microbial diversity decreased as the cresol concentration increased. The functional strains acquired under toxic stress by dosed cresols that individually degraded m-, p-, and o-cresols were identified. Catechol 1,2-dioxygenase (C12D) and catechol 2,3-dioxygenase (C23D) activities in cell-free extracts were determined spectrophotometrically and were correlated with noted changes in microbial communities under cresol stress. The proposed toxicity-to-extinction approach is feasible for isolating a functional consortium from sludge for cresol degradation.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Kuo-Ling
authors.initials: KL
authors.lastname: Ho
authors.forename: Yu-You
authors.initials: YY
authors.lastname: Chen
authors.forename: Duu-Jong
authors.initials: DJ
authors.lastname: Lee
mesh_terms: D001419:Bacteria / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001483:Base Sequence; D001673:Biodegradation, Environmental / Q000187:drug effects; D003408:Cresols / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity*; D049308:Dioxygenases / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007536:Isomerism; D007700:Kinetics; D008954:Models, Biological; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*
chemical_list: D003408:Cresols; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D049308:Dioxygenases; C077977:cresol