Preparation And The Flocculating Mechanism Of Flocculant RL-2

At present, the flocculating mechanisms of microbial flocculants have not been studied in detail, only put forward some hypotheses, for example, adhesion hypothesis, esterification theory, extracellular fiber theory and bridging theory. So there are many flocculant-producing strains, and complicate componant and construction of the flocculant, with the same object of study, different bioflocculants have different flocculating mechanism. The key research of this paper are the flocculating performance research, flocculation, and the flocculating mechanism as well as actual application, the following works have been mainly carried out in this research.(1)4 strains produced bioflocculants ( RL-2, NH-4, RT-4 and NL-3) were screened from soil and activated sludge samples. Further optimization selection, a flocculant-producing strain Bacillus sp.RL-2 with high flocculating activity was isolated from the activated sludge of the wastewater treatment plant in Chongqing. indicated that RL-2 strain produces flocculant performance most excellent, it is identified as Bacillus brives based on its colony character,morphological and physiological characteristics, using the partial 16S rRNA sequencing method. The bioflocculant was released into the culture broth in parallel with cell growth , and the flocculant main distributed in the broth, only a little adhered in the interface of cell. This suggests that the bioflocculant was produced by biosynthesis and secrete extracellular biopolymeric flocculant.(2)For the raising flocculating activity, The optimum conditions for producing flocculant were set up. The favourable substrate and culture condition for flocculant formation are:glucose as carbon source, yeast extract and (NH4)2SO4 as nitrogen source, medium initial pH, culture temperature and the speed of shake are7.0, 30℃and 120...