Isolation and identification of novel, native geosmin and 2-methylisoborneol degrading bacteria

ABSTRACT Geosmin and 2-methylisoborneol (2-MIB) are compounds responsible for taste and odor issues in water, rendering drinking water unpalatable and prompting customer complaints. The present study aimed to identify geosmin and 2-MIB degrading bacteria. The Biolog MT2 assay was used to determine bacterial metabolism on geosmin and 2-MIB. Out of 123 native bacteria screened using the Biolog MT2 assay, 73 freshwater bacterial isolates tested positive. Degradation kinetics identified 10 bacteria capable of degrading both geosmin and 2-MIB. These bacteria were further characterized through 16S rDNA sequencing and BLASTn analyses (Myroides xuanwuensis, Providencia vermicola, Providencia rettgeri, Myroides odoratitimus, Proteus mirabilis, Bacillus cereus, Bacillus subtilis, Acinetobacter guillouisae, Acinetobacter indicus, and Pseudomonas stutzeri). Bacteria A. guillousae and A. indicus were identified as capable of degrading both geosmin and 2-MIB; to our best knowledge, this is the first such report for the above genera. Importantly, the degradation was pronounced following the lag phase, which points to a ‘metabolic’ gap between growth initiation and exponential growth. In contrast, the secondary growth phase was the most productive for the degradation of taste and odor (T&O) compounds for some species. This study analyses T&O compounds, widening the research landscape while introducing new bacterial candidates for the biochemical degradation of these two compounds.