Optimization of Brucella abortus S99 Lipopolysaccharide Extraction by Phenol and Butanol Methods

摘要

Brucella abortus S99 Lipopolysaccharide (LPS) extracted and purified by phenol and butanol methods after submerged culture in the fermentor and then the optimization of these two methods carried-out by some modifications to increase the yield of extraction and LPS content and also to decrease the protein and nucleic acid content of extracted samples. Extracted samples chemically characterized by LPS and Ketodeoxyoctanate (KDO) content measurement and the evaluation of protein and nucleic acid contamination. LPS and KDO content of optimized phenol extracted sample have been more than other extracted samples (146 EU mL 1 and 1.8%, respectively) and protein contamination of this sample has been less than the sample extracted by phenol (Westphal and Jann) method (2 versus 2.7%). Optimization of butanol method led to higher content of LPS and KDO in comparison with butanol (Morrison and Leive) method. Finally among four evaluated extraction methods (butanol, phenol, optimized butanol and optimized phenol), the optimized phenol extraction of Brucella abortus S99 lipopolysaccharide reported as the best method for industrial purposes (e.g. antigen production for diagnosis of brucellosis) based on chemical characterization of extracted samples.