枯草芽孢杆菌B2菌株产生的表面活性素变异体的纯化和鉴定

利用6mol/L HCI沉淀枯草芽孢杆菌B2菌株的去细胞培养液，甲醇抽提获得脂肽类抗生素粗提物，过Sephadex LH-20层析柱获得粗纯化物，经MALDI-TOF-MS检测表明B2菌株仅含有表面活性素一种脂肽类抗生素。利用HPLC SMART SYSTEM，将粗纯化物过μPRC C2／C18层析柱对表面活性素变异体进行分离后获得纯化物。经MALDI-TOF-PSD—MS对纯化物的结构分析表明，B2菌株的表面活性素变异体由13、14和15个碳原子的脂肪酸链以及L-Glu-L-Leu—D—Leu—L-Val-L-Asp-D—Leu-L-Leu七环肽组成。

Purification and Identification of Surfactin Isoforms Produced by Bacillus subtilis B2 Strain

Crude lipopeptide was extracted with methanol from the pellet which was precipitated with 6 mol/L HCl from the culture medium of Bacillus subtilis B2 strain. The crude lipopeptide was purified by gel filtration on Sephadex LH-20 column, the obtained product was referred to as sub-pure lipopeptide. The MALDI-TOF mass spectrum showed that B2 produced only lipopeptide surfactin. Sub-pure lipopeptide was run on muRPC C2/C18 column by HPLC SMART SYSTEM with aim at separation of surfactin isoforms. The surfactin isoforms fractions was detected by MALDI-TOF-PSD mass spectrometry, results indicated that the surfactin isoforms of B2 strain was cyclic lipodecapeptide L-Glu-L-Leu-D-Leu-L-Val-L-Asp-D-Leu-L-Leu containing fatty acid with a side chain length of 13, 14 and 15 carbon atoms.