title: Carbon sources influence the nitrate removal activity, community structure and biofilm architecture.
abstract: Influence of the frequently used carbon sources in nitrate removal processes were evaluated in a lab-scale biofilm reactor. The NO3-N removal efficiency was in the order acetate>glucose>methanol>ethanol. Acetate-fed biofilm reduced nearly 100% NO3-N with negligible amount of NO2-N accumulation. Although 99% NO3-N was reduced in the glucose-fed biofilm, substantial NH3-N and NO2-N accumulated. Methanol-fed biofilm reduced 72% of NO3-N with accumulation of 2.2 mg L(-1) of NO2-N, while biofilm formed in presence of ethanol showed 61% reduction in NO3-N although relatively higher ratio of denitrifiers were observed. Acetate and ethanol-fed biofilm displayed characteristic biofilm architecture with voids, but the former had relatively higher thickness and diffusion distance. In presence of glucose and methanol, a confluent biofilm without characteristic voids was formed. Pseudomonas sp. numerically dominated the acetate and ethanol-fed biofilm, while Enterobacter sp. and Methylobacillus sp., were abundant in glucose and methanol biofilms respectively.
authors.affiliation: Department of Microbiology and Biotechnology Centre, Faculty of Science, The M. S. University of Baroda, Vadodara, Gujarat 390 002, India.
authors.forename: C S
authors.initials: CS
authors.lastname: Srinandan
authors.forename: Glen
authors.initials: G
authors.lastname: D'souza
authors.forename: Nidhi
authors.initials: N
authors.lastname: Srivastava
authors.forename: Binaya Bhusan
authors.initials: BB
authors.lastname: Nayak
authors.forename: Anuradha S
authors.initials: AS
authors.lastname: Nerurkar
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D001673:Biodegradation, Environmental / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects*; D019149:Bioreactors / Q000382:microbiology; D002244:Carbon / Q000494:pharmacology*; D015169:Colony Count, Microbial; D058645:Denaturing Gradient Gel Electrophoresis; D058440:Denitrification / Q000187:drug effects; D005798:Genes, Bacterial / Q000235:genetics; D014644:Genetic Variation / Q000187:drug effects; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009566:Nitrates / Q000302:isolation & purification*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014865:Waste Disposal, Fluid
chemical_list: D009566:Nitrates; D012336:RNA, Ribosomal, 16S; D002244:Carbon