Determining the impacts of environmental parameters on model microbial community dynamics isolated from Rustumihia WWTP/Iraq

Abstract

The composition of Rustumihia microbial community and their diversity with o-xylene-contaminants were investigated by applying molecular techniques, Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR and DGGE) via investigating 16S rRNA gene fragments and understand the interrelationships between microbial community composition and structure for established microbial model community isolated from Rustumihia WWTP. To this end, that the established consortium could be used to assess the microbial response as defined by diversity and richness shifts, which are linked to changes in growth conditions. In this research paper a synthetic consortium was created by isolating indigenous microbial community members from the Rustumihia WWTP and subjecting consortium to different pH of (6.5, 7.0 and 7.5) and o-xylene concentrations of (0.5, 5 and 50 Mm) and temperatures (25°C, 35°C, 45°C and 55°C). The results of this study indicated that the high o-xylene concentration of 50 mM was tolerated and degraded effectively at 35°C and 55°C, and pH 6.5 (P < 0.001). Bacterial richness and diversity were recorded according to the Hill parameters of 0 D, 1 D and 2 D under each of the growth conditions, and then linked to the o-xylene degradation efficiency. At 35°C and pH 6.5, the consortium achieved high degradation percentage for each of 0.5, 5 and 50 mM of o-xylene with values 73.1%, 94.8% and 63.08%, respectively. The current study is the first of its kind in Iraq. It investigates the enrichment, isolation, and identification of a microbial community from the Rustumihia WWTP and determines the efficiency of the isolates to tolerate and degrade o-xylene, highlighting their sole source of hydrocarbon. This research underscores the usefulness of molecular techniques for both diversity and richness to understand the ecological impact of o-xylene as a contaminant and to identify potential molecular techniques for detection of gene that is responsible for o-xylene degradation.