IOSR Journal of Pharmacy and Biological Sciences (IOSR-JPBS) e-ISSN: 2278-3008, p-ISSN:2319-7676. Volume 9, Issue 5 Ver. I (Sep -Oct. 2014), PP 103-114 www.iosrjournals.org www.iosrjournals.org 103 | Page Bioflocculants Produced by Bacterial Isolates from Egyptian soil 1-Characterization and Application of Extracellular Bioflocculants and Nanoparticles for Treatment of River Nile Water 1 Rawhia A. Arafa, 2 Mahmoud N. El-Rouby, 3 Hend A. Abass and 1 Zakia A. Abo El-khier 1 Botany and Microbiology Department, Faculty of Science, El Azhar University, Egypt 2 Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Egypt 3 Water Central Laboratories of Cairo, Egypt Abstract: Bioflocculants are essentially polymers produced by microorganisms during their growth . In the present study, screening of twenty eight bacterial isolates producing flocculating substances were carried out .They were isolated from cultivated soil from El-Qanater El-Khayria, Egypt and the raw water samples tested [ River Nile water] have been collected from Ismailia Canal ( about 13Km 2 from EL-Marge station for water treatment plant). From all isolates , two isolates that secret a largest amount of bioflocculant were selected . Based on16S rRNA gene sequencing and its morphological, physiobiochemical, characteristics, the isolates were identified as Bacillus cereus and Bacillus thuringiensis respectively . Maximum bioflocculant producing activity percent in water samples was affected by pH between 7-8 and at temperature rang 30- 40 o C and during growth period of strains from 72 to 96 h .The biopolymer flocculants named FQ-B1 and FQ-B2, produced by Bacillus cereus and Bacillus thuringiensis were precipitated chemical elemental analyses and UV scan were achieved for investigating the purified bioflocculant. In two isolates bioflocculants , total carbohydrate content were 0.524 μg/ 1m (16.99%) and 0.321 μg/ 1ml (15.27%) respectively , while the total protein content were 2.56 μg/ 1ml (83.01%) and 1.78 μg/ 1ml (84.73%) respectively. There are 18 types of mino acid were determined in both bioflocculants and the highest amino acid were Aspartic acid (14.9 μg/ 1ml), and Leucine (25.88 μg/ 1ml) . The present results anticipated that FQ-B1 and FQ-B2 had flocculating activity range from 75% to 76.3% and potential of application in raw water treatment, owing to their effective bioflocculation effective and harmlessness towards humans and the environment . Application of Silver 30 nm & Gold 60 nm nanoparticles alone and in conjugation with bacterial bioflocculants exhibited efficient flocculation capabilities in the treatment of River Nile water .Using Gold and silver nanoparticles alone in raw water treatment was approximately similar to that obtained two bioflocculants FQ-B1and FQ-B2 and the conjugation of nanoparticles with bioflocculants ranged from (75 to 80%) .Transmission electron microscopy(TEM) observed images of the nanoparticles irregular circular in group or in linear shape,when conjugation with bioflocculants, nanoparticles trapping and converted to a large sponge structure , this refered to highly flocculating efficiency without addtion nanoparticles . Key words: Bacillus cereus and Bacillus thuringiensis. , Bioflocculant, Flocculating activity, Water treatment, Gold and silver nanoparticles . I. Introduction The human attentions to the quality of drinking water go more than five thousand years. The purpose and limited extent have been used during the historical periods for treatment processes were boiling, filtration and sedimentation, and add some salts. In the eigheenth and nineteenth century a lot of serious attempts in the countries of Europe and Russia to advance the technology of water treatment. Famous salts that used in water and wastes sedimentation were aluminum sulfate and ferric chloride, and some assistance such as certain organic polymers can used to remove many organic compounds that cause a change in the taste and odor of water. The high turbidity observed with the use of aluminum sulfate as a coagulant can be due to the production of aluminum hydroxide precipitate in water. Besides being voluminous, the alum sludges are gelatinous, acidic , and difficult to dewater and dispose in the environment (Buthelezi et al., 2009) . Flocculants have been widely used in a variety of industrial processes, such as waste water treatment, the food and fermentation industries, drinking water purification, and industrial downstream processes (Shih et al., 2001 and Wu & Ye, 2007). Flocculating agents are generally classified into three groups: (a) inorganic flocculants, such as aluminum sulfate and poly-aluminum chloride; (b) organic synthetic flocculants, such as poly-acrylamide derivatives and