Biodegradation of monohalogenated alkanes by soil NH3-oxidizing bacteria

• Published in: Applied microbiology and biotechnology Vol. 59; no. 4/5; pp. 535 - 539
• Main Authors: Duddleston, K.N, Arp, D.J, Bottomley, P.J
• Format: Journal Article
• Language: English
• Published: Berlin Springer 2002; Springer Nature B.V
• Subjects: alkanes; ammonia; Bacteria; Biodegradation; Biodegradation of pollutants; Biological and medical sciences; Biotechnology; calcium; calcium hydroxide; cell suspension culture; Environment and pollution; Field capacity; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Loam soils; methanotrophs; methyl bromide; Nitrosomonas europaea; Silt loam; silt loam soils; Slurries; Soils; Biodegradation; Pollutant; Soils; Bacteria; Hydrocarbon; Alkane
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-002-1031-7

Although cooxidative biodegradation of monohalogenated hydrocarbons has been well studied in the model NH3-oxidizing bacterium, Nitrosomonas europaea, virtually no information exists about cooxidation of these compounds by native populations of NH3-oxidizing bacteria. To address this subject, nitrifying activity was stimulated to 125-400 nmol NO3(-) produced g(-1) soil h(-1) by first incubating a Ca(OH)2-amended, silt loam soil (pH 7.0+/-0.2) at field capacity (270 g H2O kg(-1) soil) with 10 micromol NH4(+) g(-1) soil for 14 days, followed by another 10 days of incubation in a shaken slurry (2:1 water:soil, v/w) with periodic pH adjustment and maintenance of 10 mM NH4(+). These slurries actively degraded both methyl bromide (MeBr) and ethyl chloride (EtCl) at maximum rates of 20-30 nmol ml(-1) h(-1) that could be sustained for approximately 12 h. Although the MeBr degradation rates were linear for the first 10-12 h of incubation, they could not be sustained regardless of NH4(+) level and declined to zero over 20 h of incubation. The transformation capacity of the slurry enrichments (approximately 1 micromol MeBr ml(-1) soil slurry) was similar to the value measured previously in cell suspensions of N. europaea with similar NH3-oxidizing activity. Several MeBr-degrading characteristics of the nitrifying enrichments were found to be similar to those documented in the literature for MeBr-degrading methanotrophs and facultatively methylotrophic bacteria.