Ben Bacha Abir, Moubayed Nadine Ms, Al-Assaf Alaa
Biochemistry Department, Science College, King Saud University, Riyadh, Saudi Arabia.
Laboratory of Plant Biotechnology Applied to Crop Improvement, Faculty of Science of Sfax, University of Sfax, Sfax, Tunisia.
Biotechnol Appl Biochem. 2016 May;63(3):378-90. doi: 10.1002/bab.1381. Epub 2015 Jul 14.
In this study, a new strain, ALA1, was identified as Staphylococcus aureus by biochemical tests, and its 16S ribosomal DNA sequence was isolated from dromedary milk. ALA1 lipase production was optimized in shake flask experiments and measured with varying pH (3-11), temperature (20-55 °C) and substrate concentrations. The maximum lipase production was recorded at pH 8 and 30 °C for up to 30 H of culture period for the S. aureus ALA1 strain. Among the substrates tested, selected carbon sources, xylose, nitrogen source, yeast extract, and olive oil (1%) were suitable for maximizing lipase production. The effects of surfactants were investigated and showed that Tween 20, Tween 80, and Triton X-100 prevented lipase production. Interestingly, isolate ALA1 was able to grow in high concentrations of benzene or toluene (up to 50% (v/v)). Moreover, the lipolytic activity of the S. aureus ALA1 lipase was stimulated by diethyl ether, whereas almost 100% of S. aureus ALA1 lipase activity was retained in 25% acetone, acetonitrile, benzene, 2-propanol, ethanol, methanol, or toluene. Because of its stability in organic solvent, the S. aureus ALA1 lipase was used as a biocatalyst to synthesize high levels of added value molecules. S. aureus ALA1 lipase could be considered as an ideal choice for applications in detergent formulations because of its high stability and compatibility with various surfactants, oxidizing agents, and commercial detergents.
在本研究中，通过生化试验鉴定出一种新菌株ALA1为金黄色葡萄球菌，并从单峰骆驼奶中分离出其16S核糖体DNA序列。在摇瓶实验中对ALA1脂肪酶的产生进行了优化，并在不同pH值（3 - 11）、温度（20 - 55℃）和底物浓度下进行测量。对于金黄色葡萄球菌ALA1菌株，在pH 8和30℃下培养30小时，脂肪酶产量最高。在所测试的底物中，选定的碳源木糖、氮源酵母提取物和1%的橄榄油适合使脂肪酶产量最大化。研究了表面活性剂的影响，结果表明吐温20、吐温80和曲拉通X - 100会抑制脂肪酶的产生。有趣的是，分离株ALA1能够在高浓度的苯或甲苯（高达50%（v/v））中生长。此外，金黄色葡萄球菌ALA1脂肪酶的脂解活性受到乙醚的刺激，而在25%的丙酮、乙腈、苯、2 - 丙醇、乙醇、甲醇或甲苯中，金黄色葡萄球菌ALA1脂肪酶的活性几乎能保留100%。由于其在有机溶剂中的稳定性，金黄色葡萄球菌ALA1脂肪酶被用作生物催化剂来合成大量高附加值分子。由于其高稳定性以及与各种表面活性剂、氧化剂和商用洗涤剂的兼容性，金黄色葡萄球菌ALA1脂肪酶可被视为洗涤剂配方应用中的理想选择。
