Bioflocculants Produced by Bacterial Isolates from Egyptian soil 1-Characterization and Application of Extracellular Bioflocculants and Nanoparticles for Treatment of River Nile Water

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 .