A Geomicrobiological Study of a Phosphate-Ore Mine in Al Jalamid, Saudi ArabiaIbrahim Mashhour, Mohammed Alshehri, Majed Albokari King Abdulaziz City for Science &Technology (KACST)Riyadh 11442, Saudi Arabia ABSTRACT: Phosphate ore is a rich source of elements and an important economic natural resource with a great use in agricultural and chemical industry. In addition, radioactive elements and heavy metals contents in phosphate rocks varies widely according to the geologic structure of the mining area. This work was set out to compare microbial communities associated with phosphate rocks in different geologic and textural profiles, accordingly 3 representative phosphate rock samples has been collected from the upper (waste), middle (soft) and lower (hard) core of a phosphate-ore mine located in Al Jalamid at the north of Saudi Arabia. X-ray diffraction (XRD) and X-ray fluorescence (XRF) were applied to determine the mineralogy of the rocks. The dominated crystal structure for upper layer was Calcite-Ca(CO₃) while Dolomite-CaMg(CO₃)₂ and Quartz-SiO₂ were in middle and lower layers, respectively. At the other hand, Phosphate concentration researched elevated level at 3.12%, 7.66% and 3.92%, of the which of whole content, for the upper, middle and lower layers, respectively. Microbiome inhabiting the phosphate-ore samples were determined using next generation sequencing (454 pyrosequencing). The most dominated species were pseudomonas putidawith percentage of 46% and 50% for both the upper and middle layers, respectively, while Saccharopolysporaflava(36%) for lower layers Samples Collection: 3 samples (triplicate) from the internal wall of an open mine phosphate-Ore north of Saudi Arabia were collected in borosilicate glass sterile bottle with screw cap and divided into three parts for biological profile (NGS) and for mineralogical compositions (XRD, XRF) Figure 1. DNAExtraction. gDNA was extracted using a PowerSoil DNA Isolation Kit (MO BIO Laboratories Inc, Solana Beach, CA, USA) and Nanodrop 1000 spectrophotometer (Thermo Fisher Scientific, Wilmington, DE 19810 USA) was used to quantify DNA extractant. Bacteriological Analysis: Mr.DNA Lab (Molecular Research LP, Shallowater, TX) has performed the Bacteriological analysis and identification using Next Generation Sequence (NGS). The primers used for 16S were: 515F (GTGCCAGCMGCCGCGGTAA) 806R (GGACTACHVGGGTWTCTAAT). XRD Analysis: A Philips PW1729 X-ray diffractometer with graphite monochromator was used for XRD analysis. XRF Analysis: Multi-element analysis was performed using Siemens SRS3000 wavelength-dispersive X-ray fluorescence spectrometer equipped with 3kW rhodium end-window tube and using Siemens SpectraPlus software. This work was set up to identify and compare the microbial communities associated with phosphate rocks in different geologic and textural profiles (layer & depth). Identification bacterial inhibiting will be utilized in development of suitable microbiological indicators to evaluate the phosphate concentration. • Practically, Geologists and mineralogists focus more at the middle layer for the economic and commercial profits of phosphate with a moderated percentage of phosphate oxide (P2O5), calcite CaCO3 and calcium oxides (CaO). • Clearly, there is bacterial profile shift along with mineralogical components among the three layers of studied mine (1). • Pseudomonas putidawere dominated in the middle layer with 50% of total bacterial profile due to the preferable niches of rich phosphate and magnesium, whereas these type of species are well known for phosphate solubilisation. • Saccharopolysporaflava were dominated in the lower layer with 36% of total bacterial profile due to the preferable niches of rich Si, which is the major composite of Quartz/Soil (SiO2), and was isolated from soil (2). • Mix spp are considered those with low existing percentage or unrelated function to the open mine ecology. Biological Profile and Mineralogical Compositions for different layers of mine; Upper (left), Mid (middle) Lower (right). (1) A. Pandey, P. Trivedi, B. Kumar, L. Palni (2006) Characterization of a Phosphate Solubilizing and Antagonistic Strain of Pseudomonas putida(B0) Isolated from a Sub-Alpine Location in the Indian Central Himalaya. Curr. Microbio. 53:102–107. (2) Z. Lu, Z. Liu, L. Wang, Y. Zhang, W. Qi and M. Goodfellow (2001). Saccharopolysporaflavasp. nov. and Saccharopolysporathermophila sp. nov., novel actinomycetes from soil. Int. J. Sys. Evolu. Microbio. 51: 319–325.