ABSTRACT
Microbial community structure of crude petroleum oil (CP)- and refined petroleum oil (RP)-contaminated soil wasinvestigated. The taxonomical and functional diversity of such soils can be a great source of information about microbialcommunity and genes involved in petroleum hydrocarbon (PHC) degradation. In this study, microbial diversity of soilscontaminated by RP from urban biome of Pune, India, and CP from agricultural biome of Gujarat, India, were assessed by16S rRNA amplicon sequencing on Illumina MiSeq platform. Association between the soil microbial community and thephysicochemical parameters were investigated for their potential role. In RP- and CP-contaminated soils, the microbiomeanalysis showed Proteobacteria as most dominant phylum followed by Actinobacteria. Interestingly, Firmicutes were mostprevailing in a CP-contaminated sample while they were least prevailing in RP-contaminated soils. Soil moisture content,total organic carbon and organic nitrogen content influenced the taxa diversity in these soils. Species richness was more inRP as compared to CP soils. Further prediction of metagenome using PICRUSt revealed that the RP and CP soils containmicrobial communities with excellent metabolic potential for PHC degradation. Microbial community contributing to genesessential for soil health improvement and plant growth promotion was also gauged. Our analysis showed promising resultsfor future bioaugmentation assisted phytoremediation (BAP) strategies for treating such soils.
ABSTRACT
Aims: Dental biofilms are complex, multi-species microorganism communities that inhabit the oral cavity in the form of dental plaque which causes dental caries and periodontal diseases. The present study aims to explore the potential of Lemon Grass Essential Oil (LGEO) extracted from Cymbopogon citratus as antimicrobial and antibiofilm agent against the microorganisms responsible for dental plaque. Study Design: Observational and comparison study. Place and Duration of Study: Research centre, Department of Microbiology, Abasaheb Garware college, Pune, India, between Dec 2012 to Jan 2017. Methodology: Three bacterial species primarily responsible for the biofilm formation were isolated from dental plaque and identified using 16S ribosomal RNA sequences. Five most primary colonizer of dental plaque organisms were acquired from the Microbial Type Culture Collection cultures. Antimicrobial as well as antibiofilm activity of LGEO, was determined against these eight biofilm forming microorganism. The antibiofilm activity of LGEO was evaluated against oral flora individually, as well as in consortium. Results: LGEO displayed excellent antimicrobial activity against eight test organisms associated with dental plaque, representing four genera namely Streptococcus, Staphylococcus, Lactobacillus and Candida. MIC of LGEO for all test organisms was determined as 1.5% (v/v). The LGEO was found to exhibit as high as 76% biofilm inhibitory activity even in the consortium, where the biofilm formation sometimes has been noted to be comparatively more than that of the individual organism, making LGEO a very promising antibiofilm agent. Conclusion: LGEO present in rampantly grown plant, Cymbopogon citratus, has remarkable antimicrobial and antibiofilm activity against the dental plaque organism and thus can be the economical, convenient, natural and nontoxic herbal material to effectively control the oral microflora associated with dental plaque.