摘要 从传统腊肉中筛选拮抗菌株,纯化鉴定新型抗菌物质并对其抗菌特性研究,为抗菌脂肽在食品防腐中的应用提供理论依据。采用抑菌圈法筛选拮抗菌株;通过酸沉淀、硅胶柱层析和半制备反相高效液相色谱分离纯化抗菌脂肽;通过傅里叶红外光谱、基质辅助激光解吸电离飞行时间质谱对脂肽鉴定。结果表明,筛选得到12株拮抗细菌,其中菌株XLP27对革兰氏阳性菌、革兰氏阴性菌以及对1株酵母菌和4株霉菌有明显抑菌作用。拮抗菌株XLP27鉴定为短小芽孢杆菌,其抗菌物质主要在稳定期合成,并在发酵60 h时达到最大产量。分离纯化得到单一组分抗菌物质,并鉴定为环状脂肽Iturin A,其由m/z 1046.182、1060.213、1074.198、1088.201和1102.175的5个同系物组成,对应脂肪酸链长度C14~C18。脂肽具有极高的热稳定性,在40~100℃下保温30 min活性基本保持不变,在较宽的pH值范围(4~10)内稳定性好,且对所有蛋白水解酶不敏感。菌株XLP27所产抗菌物质主要是脂肽Iturin A,具有广谱抑菌活性,稳定性良好,有潜力在食品保鲜和农业生物防治领域替代传统抗菌剂使用。 This study aimed to isolate and identify antagonistic bacteria from traditional smoked bacon,to determine the bacteriostatic activity of one selected isolate,and to purify and identify lipopeptide from its fermentation broth for the purpose of providing a theoretical basis for the application of the antimicrobial lipopeptide in food preservation.The inhibition zone method was adopted for screening the antagonistic strains.The antimicrobial lipopeptide was isolated and purified using a simple three-step procedure involving acid precipitation,silica gel column chromatography and reversedphase high performance liquid chromatography(RP-HPLC),and it was identified by Fourier transform infrared spectroscopy(FT-IR)and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).A total of 12 bacterial isolates were obtained,including XLP27,which had obvious antifungal and antibacterial effects on both Gram-positive and Gram-negative strains as well as one yeast strain and four mould strains.The antagonistic strain XLP27 was identified as Bacillus pumilu.The antibacterial substances produced by strain XLP27 were synthesized mainly in the stationary growth phase and the maximum yield was reached after 60 h of culture.One antimicrobial compound was purified from the fermentation broth and identified as lipopeptide iturin A,which had five isoforms with protonated masses of m/z 1046.182,1060.213,1074.198,1088.201 and 1102.175,representing fatty acid chain length of C14–C18.The lipopeptide was extremely heat stable(30 min at 40–100℃),remained active over a wide pH range(4–10)and was found to be resistant to all proteolytic enzymes tested.Iturin A had broad-spectrum antibacterial activity and good stability,and thus could have the potential to be an alternative to traditional antibacterial agents in the fields of food preservation and agricultural biological control.
出处 《食品科学》 EI CAS CSCD 北大核心 2021年第8期129-136,共8页 Food Science
基金 江苏省高等学校自然科学研究重大项目(20KJA180008) 江苏省苏北科技计划项目(XZ-SZ201819 BC2013417 BN2015021) 徐州市科技计划项目(KC17083)。
分类号 Q819 [生物学—生物工程]
