Aisha Anwar2025-11-212025-11-212022https://escholar.umt.edu.pk/handle/123456789/11298Arsenic, a toxic metalloid widely distributed throughout natural waters and soils,spreads both due to industrialization and natural processes. Bioremediation has been implicit as a productive and an economical approach for the removal of arsenic frompolluted sites. This study started with an objective of isolating arsenic-resistant bacteria from the heavy-metal contaminated site and to check their ability to suppor plant growth in arsenic contaminated soil. The sampling was done from an industrial sewage, located in Lahore (Pakistan). Two bacterial isolates coded A1 and A2 were characterized based on their high-resistance towards As(V) up to 60mM. Bacteria also showed resistance towards As(III) (up to 12.5mM) and Hg(II) (up to 18mM). Qualitative testing represented the isolates as arsenate-reducing with pH 7 and 37oCas optimal growth parameters. As(V) reduction pattern during the bacterial growt was also analyzed and it was found that increasing concentration of As(V) was reduced as the growth of the bacteria increased. The reduction potential i.e. conversion of As(V) to As(III) by the isolates A1 and A2 was found to be 72% and 54%, respectively. The bioremediation potential of bacterial isolates A1 and A2 was analyzed as inocula for Vigna radiata in presence and absence of arsenic hyper accumulator fern Pteris vittata. The experiment resulted in significant increase in root and shoot length of the plants treated with As(V) + P. vittata. However, root length zz was found to be relatively more affected than shoot length due to the presence of As(V) in association with P. vittata. Through 16S rRNA gene sequencing, isolate A1 was found homologous to Pseudomonas sp., and the isolate A2 exhibit homology to Exiguobacterium sp., respectively. Results clearly depicted that the isolates exhibitedthe potential to be used as inocula for phytoremediation of As-contaminated sites as they were found helpful in mitigating the toxic effect of arsenic in soilenThesis