It has been reported that certain biomass-degrading bacteria can produce bioflocculant through directly utilizing untreated biomass as carbon source. However, little is known about the synthesis mechanism of bioflocculant in these bacteria. In this study, a biomass-degrading bacterium Pseudomonas sp. HP2 showing excellent production ability of bioflocculant was isolated from the forest soil. The HP2 strain secreted alkali-thermo-tolerant CMCase and xylanase, with the maximum activities of 0.06 and 1.07 U ml-1, respectively, when the untreated rice straw was used as carbon source. The maximum flocculating efficiency with the value of 92.5% was produced from untreated rice straw by HP2 strain. Component analysis showed that this bioflocculant was abundant in the amino acids and monosaccharides with the total contents of 384.9 and 478.3 mg g-1 dry bioflocculant, respectively. The most amino acid and monosaccharide in this bioflocculant were proline and rhamnose, which accounted for 26.5% and 33.3% of total amino acids and total monosaccharides, respectively. To explore the synthesis mechanism of bioflocculant in HP2, the genome of HP2 strain was measured by Illumina HiSeq PE150 platform. The results showed that the genome of HP2 strain possessed abundant CAZy family related genes, which may play an important role in biomass degradation and bioflocculant synthesis.
Keywords: Bioflocculant; Biomass-degrading bacterium; CAZy family genes; Genome; Pseudomonas sp. HP2.
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