Khaled A. Selim et al./ Elixir Bio Tech. 108 (2017) 47449-47453 47449 I. Introduction Natural titanium dioxide exists in nature in one of three crystalline forms, the two most important of which are anatase and rutile, the third being brookite. Although these minerals are essentially pure titanium dioxide, they do not appear white, because of the presence of impurities, such as iron, chromium, or vanadium, which darken them. Rutile is the thermodynamically stable form of titanium dioxide; Titanium dioxide anatase rapidly transforms to rutile above 700 o C. Rutile melts between1830 o C and 1850 o C [1-2]. Titanium is the ninth most common element in the earth‟s crust. TiO 2 is typically thought of as being chemically inert. Titanium dioxide has been used for many years in a vast range of industrial and consumer goods including paints, coatings, adhesives, paper and paperboard, plastics and rubber, printing inks, coated fabrics and textiles, catalyst systems, ceramics, floor coverings, roofing materials, cosmetics and pharmaceuticals, water treatment agents, food colorants and in automotive products, etc …. Kaolinite group is one from the four major groups of the Clay minerals‟ groups. This group has a formula of Al 2 Si 2 O 5 (OH) 4 . The general structure of the kaolinite group is composed of silicate sheet (Si 2 O 5 ) bonded to aluminum oxide/hydroxide layers (Al2 (OH)4) called gibbsite layers. Pure kaolinite (Al 2 O 3 .2SiO 2 .2H 2 O) is white in color. Typical impurities present in kaolin ore are quartz, iron oxides, titanoferrous minerals, mica, feldspar, organic matter, etc. Ferruginous and titanoferrous minerals are the common coloring impurities present in kaolin. Iron stained titania (titanoferrous) gives dirty yellow color to kaolin. The main coloring impurity, particularly in the ultrafine size range, is titanoferrous minerals as anatase (TiO 2 ) which represents one of the major discoloring impurities in kaolin [3-4]. The most promising new approach based on integral green chemistry methods that could be used to remove these coloring materials from kaolin is the biotechnological approach. This paper aims to study the role of interaction between one isolate of Staphylococcus gallinarum and titanium dioxide and its effect on the surface properties of anatase single mineral through the study of zeta potential, adsorption and adhesion measurements. 2. Material and methods 2.1. Materials Sample of anatase single mineral of was delivered from „Wards‟ Company, USA. The purity 99% of the samples was confirmed using XRF. The –200 mesh fractions were used in adsorption. Analytical grade HCl and NaOH, from Aldrich, were used for pH regulations [5]. 2.2. Characterization A Philips PW 1730 powder X-ray diffractometer with Fefiltered Co (K-alpha) run at 30 kV and 20 mA was used to examine single titanium dioxide mineral. Infrared vibrational spectra were recorded on a Nicolet Magna 750 Fourier- transform spectrometer. For each sample, 28 scans were accumulated over the 4000-400 cm–1 spectral range employing the transmittance mode and a resolution of 4 cm– 1. The pressed KBr disc employed for this purpose was prepared using 0.4 mg of sample and 200 mg of KBr. Selected samples were observed on fractured surface under a JSM-6400 scanning electron microscope (SEM) to examine the morphology of single mineral [5]. 2.3. Isolation and Growing of Bacteria Bacterial strain was isolated from surface of Egyptian kaolin ore through vigorous agitation of kaolin sample with 0.4% sodium chloride, NaCl, solution for 30 min on a rotary shaker at 30°C, and allowed to settle. The supernatant obtained was serially diluted with sterile water and spread on the surface of nutrient agar plates which were incubated at 30 ºC. Eighteen bacterial isolates were isolated, purified by streaking on nutrient agar plates, then transferred to nutrient agar slopes stored at 4C° and subcultured monthly. The efficiency of these isolates was screened using a laser particle size analyzer [5-7]. Tele: E-mail address: m.rostom.asrt@gmail.com © 2017 Elixir All rights reserved ARTICLE INFO Article history: Received: 26 May 2017; Received in revised form: 24 June 2017; Accepted: 5 July 2017; Keywords Staphylococcus Gallinarum, Anatase, Adsorption and Adhesion. Bio-Surface Modification of Titanium Dioxide Mineral Khaled A. Selim 1 , Merit Rostom 2 , Nagui A. Abdel-Khalek 1 , Samah M. El-Sayed 1 1 Central Metallurgical Research and Development Institute (CMRDI), Helwan, Egypt. 2 Academy of Scientific Research and Technology, ASRT, Cairo, Egypt. ABSTRACT Titanium (Ti) is a major impurity in the economic Carboniferous and Cretaceous sedimentary kaolin deposits in Egypt. It is found that Ti is present as an independent mineral phase rather than in the crystal structure of kaolinite. Ti occurs mainly as uniform very fine-grained and rounded anatase crystals in pockets within the kaolin mass of all deposits. The optical properties of kaolin (brightness, Lab color, whiteness and yellowness) are improved only when the coloring impurities are removed. In this paper, the role of micro-organisms on the surface properties of titanium dioxide (anatase mineral) has been studied through zeta potential and adhesion measurements as well as the adsorption experiments. Complete characterization of both single mineral and bacteria isolated from its surface has been done using XRD, SEM, and FTIR as well as morphological and biochemical identification of bacterial isolates. © 2017 Elixir All rights reserved. Elixir Bio Tech. 108 (2017) 47449-47453 Bio Technology Available online at www.elixirpublishers.com (Elixir International Journal)