Cooperative biodegradation of geosmin by a consortium comprising three gram-negative bacteria isolated from the biofilm of a sand filter column

Abstract

Aims: To isolate and identify bacteria from a sand filter column capable of degrading the taste and odour compound, geosmin. In doing so, to investigate if these organisms degrade geosmin either individually or if an alternative mechanism is utilized. Methods and Results: Geosmin‐degrading bacteria from a biologically active sand filter column were enriched by their growth in a minimal medium supplemented with geosmin as the sole carbon source. By day 51, 21·7 mg l−1 of geosmin had been degraded as determined by solid‐phase microextraction gas chromatography/mass spectrometry, and was accompanied by a 2·12 log10 increase in active bacterial numbers as measured using the BacLightTM bacterial viability kit and flow cytometric enumeration. During the onset of geosmin degradation, the predominance of three bacteria, most similar to previously cultured species of Sphingopyxis alaskensis, Novosphingobium stygiae and Pseudomonas veronii based on 16S rRNA gene sequences was detected by denaturing gradient gel electrophoresis. Subsequent isolation of these organisms revealed that degradation of geosmin, when present as either the sole carbon source (ranging from 40 ng l−1 to 20 mg l−1) or when spiked into sterile reservoir water (37 and 131 ng l−1), occurred only when all three isolates were present. None of the isolates was shown to be capable of degrading geosmin either individually or in any combination of two. Conclusions: This study has reported, for the first time, the cooperative degradation of geosmin by a consortium comprising three gram‐negative bacteria isolated from a biologically active sand filter column. Significance and Impact of the Study: These results are important for researchers currently employing molecular‐based approaches to further understand the biodegradation of geosmin by bacteria, as such studies may be complicated by the discovery of geosmin degradation occurring by a consortium. This study also advances the knowledge surrounding the types of bacteria capable of degrading the taste and odour compound, as investigations to date regarding this are limited.

Cyanobacterial population and harmful metabolites dynamics during a bloom in Yanghe Reservoir, North China

“…A range of factors can be important for the loss of geosmin in natural waters including biodegradation and volatilization (Lin et al, 2007). Some gram-negative (Hoefel et al, 2006) and gram-positive (Saadoun and el-Migdadi, 1998) bacteria, Pseudomonas sp., Alphaproteobacterium sp., Sphingomonas sp. were reported to be involved in the biodegradation of geosmin.…”

Cooperative Mn(II) oxidation between two bacterial strains in an aquatic environment

“…strain WY was able to bypass the limitations of each individual species with regard to degradation of butyl benzyl phthalate (Chatterjee and Dutta, 2008). Three gram-negative strains, including one strain of genus Sphingopyxis, are only capable of degrading geosmin when they are combined as a whole group (Hoefel et al, 2006). The emergent biochemical properties generated from interspecific interactions contribute to our general knowledge of single strain functions, and provide us with an alternative method to accomplish various tasks, such as identification of new fungi-derived pharmaceuticals (Bertrand et al, 2014;Ochi and Hosaka, 2013) and degradation of organic contaminants (Liu et al, 2014;Wu et al, 2010;Zhang et al, 2013).…”

Earthy odor compounds production and loss in three cyanobacterial cultures

“…and Sphingomonas sp. (Elhadi et al, 2004(Elhadi et al, , 2006Ho et al, 2007;Hoefel et al, 2006;Saadoun and el-Migdadi, 1998;Saito et al, 1999). Bacteria including Pseudomonas sp.…”