Chi Zhe, Rong Yan-Jun, Li Yang, Tang Mei-Juan, Chi Zhen-Ming
Unesco Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China.
Bioprocess Biosyst Eng. 2015 May;38(5):853-61. doi: 10.1007/s00449-014-1328-9. Epub 2014 Nov 19.
In this work, the anti-Escherichia coli activity of the bioactive substances produced by Bacillus amyloliquefaciens R3 was examined. A new and cheap medium for production of the anti-E. coli substances which contained 20.0 g L(-1) soybean powder, 20.0 g L(-1) wheat flour, pH 6.0 was developed. A crude surfactant concentration of 0.48 mg mL(-1) was obtained after 27 h of 10-L fermentation, and the diameter of the clear zone on the plate seeded with the pathogenic E. coli 2# was 23.3 mm. A preliminary characterization suggested that the anti-E. coli substances produced by B. amyloliquefaciens R3 were the biosurfactins (F1, F2, F3, F4, and F5) with amino acids (GLLVDLL) and hydroxy fatty acids (of 12-15 carbons in length). It was found that all the strains of the pathogenic E. coli showed resistance to several different antibiotics, suggesting that they were the multi-drug resistance and all the strains of the pathogenic E. coli were sensitive to the biosurfactins, indicating that the biosurfactins produced by B. amyloliquefaciens R3 had a broad spectrum of antibacterial activity against the pathogenic E. coli with multi-drug resistant profiles. After the treatment with the purified biosurfactin (F1), the cell membrane of both the whole cells and protoplasts of the E. coli 2# was damaged and the whole cells of the bacterium were broken.
在本研究中，检测了解淀粉芽孢杆菌R3产生的生物活性物质的抗大肠杆菌活性。开发了一种新型廉价的用于生产抗大肠杆菌物质的培养基，其含有20.0 g L⁻¹大豆粉、20.0 g L⁻¹小麦粉，pH 6.0。经过10-L发酵27小时后，获得了浓度为0.48 mg mL⁻¹的粗表面活性剂，接种致病性大肠杆菌2#的平板上透明圈直径为23.3 mm。初步表征表明，解淀粉芽孢杆菌R3产生的抗大肠杆菌物质是具有氨基酸（GLLVDLL）和羟基脂肪酸（碳链长度为12 - 15个碳）的生物表面活性剂（F1、F2、F3、F4和F5）。研究发现，所有致病性大肠杆菌菌株对几种不同抗生素均表现出抗性，表明它们具有多重耐药性，并且所有致病性大肠杆菌菌株对生物表面活性剂均敏感，这表明解淀粉芽孢杆菌R3产生的生物表面活性剂对具有多重耐药性的致病性大肠杆菌具有广谱抗菌活性。用纯化的生物表面活性剂（F1）处理后，大肠杆菌2#的全细胞和原生质体的细胞膜均受到损伤，细菌的全细胞破裂。
