Unraveling the Microbial Interactions and Metabolic Potentials in Pre- and Post-treated Sludge from a Wastewater Treatment Plant Using Metagenomic Studies

Abstract

Sewage waste represents an ecosystem of complex and interactive microbial consortia which proliferate with different kinetics according to their individual genetic as well as metabolic potential. We performed metagenomic shotgun sequencing on Ion-Torrent platform, to explore the microbial community structure, their biological interactions and associated functional capacity of pre-treated/raw sludge (RS) and post-treated/dried sludge (DS) of wastewater treatment plant. Bacterial phylotypes belonging to Epsilonproteobacteria (∼45.80%) dominated the RS with relatively few Archaea (∼1.94%) whereas DS has the dominance of beta- (30.23%) and delta- (13.38%) classes of Proteobacteria with relatively greater abundance of Archaea (∼7.18%). In particular, Epsilonproteobacteria appears as a primary energy source in RS and sulfur-reducing bacteria with methanogens seems to be in the potential syntrophic association in DS. These interactions could be ultimately responsible for carrying out amino-acid degradation, aromatic compound degradation and degradation of propionate and butyrate in DS. Our data also reveal the presence of key genes in the sludge microbial community responsible for degradation of polycyclic aromatic hydrocarbons. Potential pathogenic microbes and genes for the virulence factors were found to be relatively abundant in RS which clearly reflect the necessity of treatment of RS. After treatment, potential pathogens load was reduced, indicating the sludge hygienisation in DS. Additionally, the interactions found in this study would reveal the biological and environmental cooperation among microbial communities for domestic wastewater treatment.

Analysis of microbial community biodiversity in activated sludge from a petrochemical plant

“…Our findings are in accordance with previous studies of activated sludge, with the predominance of Proteobacteria (Xia et al, 2010). Sidhu et al (2017) characterized and dissected the phylogenetic and functional structures from the sludge community at the phylum level and found the dominance of Proteobacteria in raw and dried sludge samples, representing 97.9% and 92.6%, respectively. Analysis of the microbial community revealed key groups for degradation of recalcitrant compounds present in the industrial effluent.…”

“…Nitrospirae shows a correlation with the presence of NTK. The ability to perform nitrite reduction was a physiological characteristic observed in Nitrospirae (Sidhu et al, 2017). According to Ward et al (2009), genomic evidence suggested that the role of acidobacteria in nitrogen cycling in soils and sediments is the reduction of nitrate, nitrite, and possibly nitric oxide due to assimilatory nitrate reductase gene sequences.…”

Microbial community dynamics and functional responses that contribute to tolerance of high concentrations of petroleum hydrocarbon

“…Then the BH medium was centrifuged for 15 min at 4 °C. A Super Flash Alumina Neutral column (SF 15–24 g, 20.8 mm × 112 mm; Agilent Technologies, Palo Alto, CA, USA) was used to separate alkanes and PAHs, which were eluted using dichloromethane and n ‐hexane respectively. The content of alkanes and PAHs was determined by gas chromatography (GC) (Bruker 430‐GC, USA).…”

“…Recently, AS has been successfully applied in the remediation of PH pollution and has shown great advantages . However, the types and concentrations of PH as well as the structure and function of the microbial community have always been the main factors which limit the efficiency of PH remediation using AS.…”

“…20,21 Recently, AS has been successfully applied in the remediation of PH pollution and has shown great advantages. 22,23 However, the types and concentrations of PH as well as the structure and function of the microbial community have always been the main factors which limit the efficiency of PH remediation using AS. Therefore we used AS to degrade different concentrations of PH and investigated the degradation rate of PH and the change of bacterial community structure during the process.…”