A novel species isolated from a bacterial consortia of contaminated soil enriched for the remediation of e-waste

The genus Pseudomonas is widespread and has been reported to occur in diverse ecological niches. Members of the genus Pseudomonas are metabolically versatile and harbor various biotechnologically important properties. Pseudomonas sesami is reported to have plant growth-promoting activity. Strains of Pseudomonas produce thermotolerant proteolytic and lipolytic enzymes which result in food spoilage. Pseudomonas putida, Pseudomonas furukawaii, Pseudomonas knackmussii and many other pseudomonads have been reported for the remediation of xenobiotic compounds. In the present study, researchers at NCMR-NCCS Pune report the detailed characterization of a Pseudomonas strain, which was isolated from soil samples from Lalkuan, Nainital, Uttarakhand, India. The strain was found to be part of the bacterial consortia obtained for developing remediation of e-waste.

The strain was Gram-stain-negative, rod-shaped, aerobic, oxidase-positive and catalase-positive. Colonies are L-form with entire margins, creamy color, umbonate elevation and non-mucoid. Cell can tolerate up to 3% salinity. Based on 16S rRNA gene sequence the strain belongs to the genus Pseudomonas and showed highest sequence similarity to Pseudomonas furukawaii followed by Pseudomonas aeruginosa and Pseudomonas resinovorans. The G+C content in the genome was 64.24mol%. The phylogenetic analysis revealed that the strain forms a distinct clade in the family Pseudomonadaceae. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The phenotypic, chemotaxonomic and genetic analysis, including overall genome relatedness index values, indicated that the strain represents a novel species of the genus Pseudomonas, for which the name Pseudomonas lalkuanensis sp. nov. is proposed.

The cells of the strain were motile as observed by using the hanging drop method. The oxidase and catalase activities were investigated using an oxidase disc and observing bubble production. The phylogenetic analysis showed that strain formed a separate clade with P. resinovorans keeping P. furukawaii and P. aeruginosa in an outer clade with strong bootstrap support. This phylogenetic analysis reveals that the strain is phylogenetically distinct from P. furukawaii and P. resinovorans. The orthoANI and dDDH values of the strain were clearly below the thresholds for the proposal of novel prokaryotic species indicating that the strain belongs to a novel species of the genus Pseudomonas.

Reference: https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijsem.0.004559