Bacterial Bioremediation: A sustainable Approach to Wastewater Treatment and Promoting the Growth of Vicia faba (L.)

This study explores the use of bacterial isolates from wastewater treatment plants in El-Gharbia Governorate, Egypt, for improving wastewater quality and enhancing the growth of Vicia faba (L.) seedlings. Twenty-five bacterial isolates were collected from various wastewater treatment stages, including influent, sedimentation tanks, aeration tanks, and effluents. Five isolates (1, 3, 7, 15, and 21) were identified as highly effective in treating wastewater whereas, isolate no.1 achieved the most significant reductions in total suspended solids (TSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). Further testing on Kafr El-Zayat wastewater showed that isolate No. 1 had ability to reduce TSS, BOD, and COD by 60%, 61%, and 68%, respectively, after two days. A mixture of the top five isolates (Tmix) improved these reductions to 65%, 68%, and 70%. Furthermore, the bacterial consortium effectively removed heavy metals such as Cd, Cr, Cu, Fe, Mn, and Pb, with removal efficiencies up to 97% for Mn and 96% for Fe. Molecular identification using 16S rRNA sequencing identified the isolates as Klebsiella sp., Proteus sp., Trabulsiella sp., Escherichia sp., and Kosakonia sp. Irrigation with treated wastewater, especially using Tmix, significantly improved the growth of Vicia faba (L.) seedlings, enhancing shoot height, fresh weight, photosynthetic efficiency, antioxidant enzyme activities, and key biochemical compounds like ascorbic acid, phenolics, and flavonoids. The treatments also increased nutrient uptake, particularly potassium and nitrogen. This study highlights bacterial bioremediation as a sustainable approach to wastewater treatment and agricultural application.