Production and characterization of a novel bioflocculant produced by Bacillus licheniformis
- 化学化工－已发表论文 
An extracellular bioflocculant-producing bacterium isolated from a contaminated activated medium was identified as Bacillus lichenoformis by 16S rDNA sequence and biochemical and physiological characteristics. The effects of cultivation conditions on bioflocculant production were investigated. The optimized initial pH of the fermentation medium was 7.2 and the inoculum concentration was 4% (v/v). Maximum flocculating activity (700 U/mL) was obtained after 48 h cultivation at 37 °C. Chemical analyses of the purified bioflocculant revealed that it was heteroglycan polymer comprising 11% of protein (w/w). The mass proportion of neutral sugar, amino sugar and uronic acid was 7.9:4:1. Infrared spectrophotometry and NMR analysis further indicated the presence of carboxyl, hydroxyl and amino groups typical for polysaccharides. SEM image of the purified bioflocculant showed that it had circular structure and its diameter was about 200 nm.