*Correspondence: eyamani@kacst.edu.sa; +966 1 481 3806 (Received: January 08, 2020; accepted: September 17, 2020) Citaton: Alyamani EJ, Booq RY, Bahkali AH, Alharbi SA. Biological Removal of Nitrates from Groundwater Resources in Saudi Arabia. J Pure Appl Microbiol. 2020;14(3):2203-2213. doi: 10.22207/JPAM.14.3.61 © The Author(s) 2020. Open Access. This artcle is distributed under the terms of the Creatve Commons Atributon 4.0 Internatonal License which permits unrestricted use, sharing, distributon, and reproducton in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creatve Commons license, and indicate if changes were made. Alyamani et al. | J Pure Appl Microbiol | 14(3):2203-2213 | September 2020 Artcle 6031 | htps://doi.org/10.22207/JPAM.14.3.61 Print ISSN: 0973-7510; E-ISSN: 2581-690X ReseARCh ARtiCle OPeN ACCess www.microbiologyjournal.org 2203 Journal of Pure and Applied Microbiology Biological Removal of Nitrates from Groundwater Resources in saudi Arabia essam J. Alyamani 1 *, Rayan Y. Booq 1 , Ali h. Bahkali 2 and sulaiman A. Alharbi 2 1 Natonal Center for Biotechnology, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia. 2 Botany & Microbiology Department, College of Sciences, King Saud University, Riyadh, Saudi Arabia. Abstract Groundwater is the main water source for many areas in saudi Arabia and the only source of water in some areas. Many local studies have reported that high nitrate concentratons in some wells of groundwater. to provide safe drinking water, the excess amounts of nitrate have to be removed by bio-denitrifcaton process. This study aims to develop a denitrifying biological flter using denitrifying bacteria immobilized on microbial cellulose for the removal of nitrates from water contaminated with nitrate. Denitrifying bacteria that can form bioflter on microbial cellulose were isolated from diferent regions in saudi Arabia and were characterized by molecular techniques. they were evaluated for their ability to analyze nitrates and to develop bioflter to remove nitrates from contaminated water. In the results of this project, an optmal microbial cellulose producton was achieved by Gluconacetobacter xylinus ATCC 23768 in the lab, which had facilitated the use of bioflter with the immobilized nitrate- reducing bacteria Pseudomonas aeruginosa. The reducton rate of nitrate was reached 1.9mg/L from the startng concentraton of 100 mg/L afer 18h. Promising results of nitrate removal rate on MC immobilized with Pseudomonas aeruginosa on bioflter at optmized lab conditons of pH, and proper carbon source were achieved. the results suggest that water contaminated with nitrate can be removed by the bio-denitrifcaton process efectvely. Keywords: Nitrate-reducing bacteria, Saudi Arabia, Biofltraton, bio-denitrifcaton, Groundwater