Production And Applications Of A Bioflocculant Produced By Ruditapes Phlippinaram Conglutination Mud

Marine biological resources are a treasure of research and development in 21 century. And the investigation of active extracts from marine biological has already become the research focus in all over the world. For the harm of traditional flocculants to human health and environment, finding new kind of bioflocculants which are biodegradable and harmless has becoming focus issue of water treatment research field.The adhered sludge of a marine shell-Ruditapes Phlippinaram was selected from Zhuanghe Dalian sea area as the researching object by contrasting four different kinds of marine shell conglutination mud which come from different habitats in Bohai bay, the mearsurement including the flocculating efficiency to Kaolin clay suspension and the decolourating efficiency to synthetic dyes. The conglutination mud of Ruditapes Phlippinaram was gathered, and 62 aerobic bacteria were cultured from the mud sample. By measuring the flocculating rate of the strains, 17 strains were selected out, whose cells or fermentation borth have the flocculating ability. The 17 strains were conserved in the inclined medium in the fridge of 4℃.The strain of ZHT4-13 was screened out as the bioflocculant producing microorganism. It was indentified as Rothia sp. accoding to its morphplogical observation, physiological and biochemical characteristics and and the result of sequences alignment of 16s rDNA. An orthogonal experiment was designed to optimize the culture conditions of ZHT4-13. The cells yield, cells flocculating abilities, microbioflocculant (MBF) yield, MBF flocculating abilities were studied with different experiment conditions. The optimum MBF producing conditions of ZHT4-13 are: carbon source-sucrose, nitrogen source-ammonium sulphate + prptone, pH-8, culturing time-4 days, and the rest medium components are: NaCl 0.5%, MgSO4·7H2O 0.1%, KH2PO4 0.5%, K2HPO4 0.2%, 30℃, 150r/min, and the inoculation amount are 108 cells /100mL.MBF4-13 was extracted from the fermentation borth of strain ZHT4-13 by ethanol-sedimentary method. The microcosmic and spectrum characters of MBF4-13 were studied preliminarily by SEM, UV-Vis, FT-IR and NMR. Polysaccharide characteristic groups were found in those spectra. So the main component of MBF4-13 was deduced as polysaccharide, which came from the outside of ZHT4-13 cytoderm. MBF4-13 is hard to dissolved in water or common organic solvent, and it has a strong flocculating efficiency for Kaolin clay in pH 1-13, and temperature 4-100℃. The flocculating rate for 5g/L Kaolin clay can come up to 86.22% when pH=9 and 20℃.The four main applications of MBF4-13 in decolouration of synthetic dyes, adsorption and wipe off of heavy mental ions, improving the performance of activated sludge and comparative the flocculent activity for 5g/L Kaolin clay with the traditional flocculants were researched in this thesis. The experiment results indicated that MBF4-13 has infinite economy and application value as a new kind of microbioflocculant.