The Effects of Cyanobacterial Exudates on Bacterial Growth and Biodegradation of Organic Contaminants

• Published in: Microbial ecology 2006-01, Vol.51 (1), p.4-12
• Main Authors: Kirkwood, A. E., Nalewajko, C., Fulthorpe, R. R.
• Format: Article
• Language: English
• Subjects: 2,4-Dichlorophenoxyacetic Acid - metabolism; Aphanothece floccosa; Aphanothece rivularis; Bacteria; Bacteriology; Biodegradation; Biodegradation, Environmental; Biological and medical sciences; Biological treatment; Biomass; Carbon - analysis; Contaminants; Culture Media; Cupriavidus necator - growth & development; Cupriavidus necator - metabolism; Cyanobacteria; Cyanobacteria - chemistry; Cyanobacteria - isolation & purification; Cyanophyta; Dichloroacetic Acid - metabolism; Freshwater; Fundamental and applied biological sciences. Psychology; Geitlerinema carotinosum; Geitlerinema ionicum; Geitlerinema pseudacusitissimum; Gram-Negative Aerobic Rods and Cocci - growth & development; Gram-Negative Aerobic Rods and Cocci - metabolism; Industrial Waste; Linear Models; Memory interference; Microbiology; Miscellaneous; Organic carbon; Organic contaminants; Organic foods; Paper industry wastes; Phenol - metabolism; Phenols; Phormidium animale; Phormidium autumnale; Phormidium insigne; Phormidium rimosum; Pseudanabaena; Pseudomonas; Pseudomonas - growth & development; Pseudomonas - metabolism; Pulp & paper industry; Pulp and paper industry; Pulp wastes; Ralstonia eutropha; Taxa; Tychonema bourrellyi; Ultraviolet Rays; Waste treatment; Wastewater; Wastewater treatment
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-004-0058-y

The pulp and paper industry largely depends on the biodegradation activities of heterotrophic bacteria to remove organic contaminants in wastewater prior to discharge. Our recent discovery of extensive cyanobacterial communities in pulp and paper waste treatment systems led us to investigate the potential impacts of cyanobacterial exudates on growth and biodegradation efficiency of three bacterial heterotrophs. Each of the three assessed bacteria represented different taxa commonly found in pulp and paper waste treatment systems: a fluorescent Pseudomonad, an Ancylobacter aquaticus strain, and a Ralstonia eutropha strain. They were capable of utilizing phenol, dichloroacetate (DCA), or 2,4-dichlorophenoxyacetic acid (2,4-D), respectively. Exudates from all 12 cyanobacterial strains studied supported the growth of each bacterial strain to varying degrees. Maximum biomass of two bacterial strains positively correlated with the total organic carbon content of exudate treatments. The combined availability of exudate and a known growth substrate (i.e., phenol, DCA, or 2,4-D) generally had a synergistic affect on the growth of the Ancylobacter strain, whereas mixed effects were seen on the other two strains. Exudates from four representative cyanobacterial strains were assessed for their impacts on phenol and DCA biodegradation by the Pseudomonas and Ancylobacter strains, respectively. Exudates from three of the four cyanobacterial taxa repressed phenol biodegradation, but enhanced DCA biodegradation. These dissimilar impacts of cyanobacterial exudates on bacterial degradation of contaminants suggest a species-specific association, as well as a significant role for cyanobacteria during the biological treatment of wastewaters.