Paenibacillus oleatilyticus sp. nov., isolated from soil.

A gram-stain-negative, endo-spore forming, facultatively anaerobic, motile, rod-shaped bacterial strain SM69T, isolated from soil samples of Rohtak, Haryana, India was characterized using polyphasic approach. White colonies were 2-3 mm, in diameter and growth occurred between 20 and 55 °C, pH 6.0-10.0 with 0-2.0% (w/v) NaCl. Based on 16S rRNA gene sequence similarity the strain is placed in the genus Paenibacillus as it is closely related to 'Paenibacillus tyrfis MSt1T' (99.7%) and P. elgii SD17T (99.6%). The cell wall peptidoglycan contained meso-diaminopimelic acid. The dominant fatty acids included anteiso-C15: 0 (50%), C16: 0 (12%) and anteiso-C17: 0 (10%). Major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The size of the draft genome was 7,848,017 bp, with 53.1% G+C content. dDDH (51.6%) and ANI (93.5%) of strain SM69T with its close relatives indicates that it represents a novel species, for which the name Paenibacillus oleatilyticus sp. nov. (Type strain SM69T = MCC 3064T = JCM 33981T = KACC 21649T) is proposed.

Integrated Genomic and Functional Characterization of the Anti-diabetic Potential of Arthrobacter sp. SW1.

For decades, bacterial natural products have served as valuable resources for developing novel drugs to treat several human diseases. Recent advancements in the integrative approach of using genomic and functional tools have proved beneficial in obtaining a comprehensive understanding of these biomolecules. This study presents an in-depth characterization of the anti-diabetic activity exhibited by a bacterial isolate SW1, isolated from an effluent treatment plant. As a primary screening, we assessed the isolate for its potential to inhibit alpha-amylase and alpha-glucosidase enzymes. Upon confirmation, we further utilized LC-MS, ESI-MS/MS, and NMR spectroscopy to identify and characterize the biomolecule. These efforts were coupled with the genomic assessment of the biosynthetic gene cluster involved in the anti-diabetic compound production. Our investigation discovered that the isolate SW1 inhibited both α-amylase and α-glucosidase activity. The chemical analysis suggested the production of acarbose, an anti-diabetic biomolecule, which was further confirmed by the presence of biosynthetic gene cluster "acb" in the genome. Our in-depth chemical characterization and genome mining approach revealed the potential of bacteria from an unconventional niche, an effluent treatment plant. To the best of our knowledge, it is one of the first few reports of acarbose production from the genus Arthrobacter.

Genomic and functional features of the biosurfactant producing Bacillus sp. AM13.

Genomic studies provide deeper insights into secondary metabolites produced by diverse bacterial communities, residing in various environmental niches. This study aims to understand the potential of a biosurfactant producing Bacillus sp. AM13, isolated from soil. An integrated approach of genomic and chemical analysis was employed to characterize the antibacterial lipopeptide produced by the strain AM13. Genome analysis revealed that strain AM13 harbors a nonribosomal peptide synthetase (NRPS) cluster; highly similar with known biosynthetic gene clusters from surfactin family: lichenysin (85 %) and surfactin (78 %). These findings were substantiated with supplementary experiments of oil displacement assay and surface tension measurements, confirming the biosurfactant production. Further investigation using LCMS approach exhibited similarity of the biomolecule with biosurfactants of the surfactin family. Our consolidated effort of functional genomics provided chemical as well as genetic leads for understanding the biochemical characteristics of the bioactive compound.

Soil mesocosm studies on atrazine bioremediation.

Accumulation of pesticides in the environment causes serious issues of contamination and toxicity. Bioremediation is an ecologically sound method to manage soil pollution, but the bottleneck here, is the successful scale-up of lab-scale experiments to field applications. This study demonstrates pilot-scale bioremediation in tropical soil using atrazine as model pollutant. Mimicking field conditions, three different bioremediation strategies for atrazine degradation were explored. 100 kg soil mesocosms were set-up, with or without atrazine application history. Natural attenuation and enhanced bioremediation were tested, where augmentation with an atrazine degrading consortium demonstrated best pollutant removal. 90% atrazine degradation was observed in six days in soil previously exposed to atrazine, while soil without history of atrazine use, needed 15 days to remove the same amount of amended atrazine. The bacterial consortium comprised of 3 novel bacterial strains with different genetic atrazine degrading potential. The progress of bioremediation was monitored by measuring the levels of atrazine and its intermediate, cyanuric acid. Genes from the atrazine degradation pathway, namely, atzA, atzB, atzD, trzN and trzD were quantified in all mesocosms for 60 days. The highest abundance of all target genes was observed on the 6th day of treatment. trzD was observed in the bioaugmented mesocosms only. The bacterial community profile in all mesocosms was monitored by LH-PCR over a period of two months. Results indicate that the communities changed rapidly after inoculation, but there was no drastic change in microbial community profile after 1 month. Results indicated that efficient bioremediation of atrazine using a microbial consortium could be successfully up-scaled to pilot scale.

Demonstration of sequential adaptation strategy for developing salt tolerance in bacteria for wastewater treatment: a study using Escherichia coli as model.

A wastewater isolate identified as Escherichia coli HPC781 was adapted for high salt concentration through sequential transfers in Luria Broth (LB). The cells were grown in LB with 5% sodium chloride (NaCl) and were analyzed for the acquired salt resistance network through gene expression profiles. Microarray studies revealed TCA, glyoxylate shunt and acetyl Co-A metabolism as key nodes for stress combat to arrive at compromised physiology. It also proposed that the cells were receiving signals from salt environment via OmpR-EnvZ two component systems and stress dependent general regulatory protein rpoH and rpoE. The salt adapted culture, when challenged with wastewater having additional 5% salt showed growth. The work represents a tactic to adjust biochemical network towards stress and reveals its applicability via real-time PCR measurement of genes in wastewater. The study proposes that the recycled biomass with an adaptation strategy could be applied for treatment of wastewater with high salt levels.