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Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants having health hazards. PAH-utilizing bacterial strains were isolated from petroleum-contaminated soil from siding area, Bijwasan supply location of BPCL, Delhi, India. Bacterial strains with different morphology were isolated and acclimatized to a mixture of low molecular weight PAH compounds in the concentration range of 50-10,000 mg/L. Two bacterial strains surviving at 10,000 mg/L PAH concentration were identified as Kocuria flava and Rhodococcus pyridinivorans, based on 16S rRNA gene sequencing and phylogenetic analysis over MEGA X, are reported for the first time for PAH degradation. The strain K. flava could degrade phenanthrene, anthracene, and fluorene with efficiency of 55.13%, 59.01%, and 63.46%, whereas R. pyridinivorans exhibited 62.03%, 64.99%, and 66.79% degradation for respective PAHs at initial PAH concentration of 10 mg/L. Slightly lower degradation of phenanthrene could be attributed to its more stable chemical structure. The consortium of both the strains degraded 61.32%, 64.72%, and 66.64%, of 10 mg/L of phenanthrene, anthracene, and fluorene, respectively, in 15 days of incubation period indicating no synergistic or antagonistic effect towards degradation. Catechol 2,3-dioxygenase (C23O), dehydrogenase and peroxidase enzyme activities during PAH degradation coincided with degradation of PAHs, thus highlighting the role of these enzymes in catabolising three-ring PAHs. This is the first investigation confirming the participation of C23O, dehydrogenase and peroxidases enzyme profiles throughout the period of degradation. The study concludes that these strains can play significant role in microbial remediation of PAH-contaminated environment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A novel actinobacterial strain, designated, NIO-1009(T), was isolated from a marine sediment sample collected from Chorao Island, Goa, India. Phylogenetic analysis comparisons based on 16S rRNA gene sequences between strain NIO-1009(T) and other members of the genus Rhodococcus revealed that strain NIO-1009(T) had the closest sequence similarity to Rhodococcus kroppenstedtii DSM 44908(T) and Rhodococcus corynebacterioides DSM 20151(T) with 99.2 and 99.1%, respectively. Furthermore, DNA-DNA hybridization results showed that R. kroppenstedtii DSM 44908(T) and R. corynebacterioides DSM 20151(T) were 39.5 (3.0%) and 41.7 (2.0%) with strain NIO-1009(T), respectively, which were well below the 70% limit for any novel species proposal. Phylogenetically strain NIO-1009(T) forms a stable clade with and R. kroppenstedtii DSM 44908(T) and R. corynebacterioides DSM 20151(T) with 100% bootstrap values. Strain NIO-1009(T) contained meso-diaminopimelic acid as the diagnostic diamino acid and galactose and arabinose as the cell wall sugars. The major fatty acids were C(16 : 0), C(18 : 1)ω9c, C(16 : 1)(ω6c and/or ω7c) and 10-methyl C(18 : 0). The only menaquinone detected was MK-8(H2), while the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and one unknown phospholipid. The G+C content of the genomic DNA was 66.9 mol%. The phenotypic and genotypic data showed that strain NIO-1009(T) warrants recognition as a novel species of the genus Rhodococcus for which the name Rhodococcus enclensis sp. nov., is proposed; the type strain is NIO-1009(T) ( = NCIM 5452(T) = DSM 45688(T))., (© 2014 IUMS.)

We report the 8.231-Mb genome sequence of Rhodococcus imtechensis RKJ300, isolated from pesticide-contaminated soil in Punjab, India. The genome sequence of the strain RKJ300 will be helpful in exploring the molecular pathways involved in the degradation of nitrophenols.

A Gram-positive actinobacterium, strain RKJ300(T), capable of utilizing p-nitrophenol and 2,4-dinitrophenol, was isolated from a pesticide-contaminated site in India. The morphological and chemotaxonomic properties of the isolate were typical of members of the genus Rhodococcus. The DNA G+C content was 72 mol%. Strain RKJ300(T) exhibited the highest level of sequence similarity with Rhodococcus wratislaviensis NCIMB 13082(T) (99.3 %), followed by Rhodococcus opacus DSM 43205(T) (98.8 %), Rhodococcus percolatus MBS1(T) (98.6 %) and Rhodococcus koreensis DNP505(T) (98.1 %). The low levels of DNA-DNA relatedness (49-58 %) with the above micro-organisms, and the differences in the biochemical and physiological properties, suggest that strain RKJ300(T) should be classified within a novel species of the genus Rhodococcus, for which the name Rhodococcus imtechensis sp. nov. is proposed. The type strain is RKJ300(T) (=MTCC 7085(T)=JCM 13270(T)).