Metagenomics analysis of rhizospheric bacterial communities ofSaccharum arundinaceumgrowing on organometallic sludge of sugarcane molasses-based distillery

The present paper aims to explore the rhizospheric bacterial communities associated withSaccharum arundinaceumgrown on organometallic pollutants-rich hazardous distillery sludge. The sequence analysis of 16S rRNA V3-V4 hypervariable region with Illumina MiSeq platform showed 621,897 OTUs derived from rhizospheric and non-rhizospheric distillery sludge samples out of 1,191,014 and 901,757 sequences read, respectively. The major phyla detected in rhizospheric sludge sample wereProteobacteria(50%),Bacteriodetes(33%),Firmicutes(5%)Gemmatimonadetes(2%),Chloroflexi(2%), andTenericutes(2%). The dominant three genera were detected asRheinheimera(21%),Sphingobacterium(17%), andIdiomarina(8%). In addition, other minor genera such as unculturedBacillus(4%),Acidothermus(4%),Bacillus(3%),Pseudomonas(2%),Flavobacterium(2%), uncultured bacterium (2%),Parapedobacter(2%),Alcanivorax(2%),Acholeplasma(2%),Hyphomonas(1%), andAquamicrobiumwere also detected (1%) in rhizospheric sludge. Our results suggested that rhizospheric bacterial communities associated withS. arundinaceumwere substantially different in richness, diversity, and relative abundance of taxa compared to non-rhizospheric sludge. Further, the comparative organic pollutant analysis from non-rhizospheric and rhizospheric sludge samples through GC-MS analysis revealed the disappearance of few compounds and generation of some compounds as new metabolic products by the activity of rhizospheric bacterial communities. The results of this study will be helpful in understanding the role of rhizospheric bacterial communities responsible for degradation and detoxification of complex organometallic waste and, thus, can help in designing appropriate phytoremediation studies for eco-restoration of polluted sites.