Application of response surface methodology to improve the production of antimicrobial biosurfactants by Lactobacillus paracasei subsp. tolerans N2 using sugar cane molasses as substrate
Application of response surface methodology to improve the production of antimicrobial biosurfactants by Lactobacillus paracasei subsp. tolerans N2 using sugar cane molasses as substrate
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DOI：
10.1186/s40643-018-0234-4
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发表时间：
2018-01-01
影响因子：
4.6
通讯作者：
Devappa, Somashekar
中科院分区：
文献类型：
--
作者：
Hippolyte, Mouafo T.;Augustin, Mbawala;Devappa, Somashekar
背景：生物表面活性剂是由多种微生物产生的天然表面活性化合物。较高的培养基价限制了生物表面活性剂的大规模生产和使用。因此，有必要开发一种高效、经济的生物工艺，以提高微生物合成生物表面活性剂的产量。本研究采用响应面法对一株乳杆菌产生物表面活性物质进行了优化，并对其抗菌活性进行了测定。结果：该菌株经鉴定为副乳杆菌亚种。16S rRNA基因分析后耐受性为N_2。在使用Plackett-Burman统计设计研究的不同变量中，温度、蛋白胨和甘蔗糖蜜浓度被发现是对生物表面活性剂生产有显著影响(p<；0.05)的主要因素。结果表明，糖蜜浓度为59.5g/L、蛋白胨浓度为6.20g/L、温度为33℃时，生物表面活性剂的产生量最高可达2.70g/L，表面张力降低了37.85mN/m，抑菌活性以抑菌直径63 mm表示。对产生的生物表面活性剂进行了元素分析、生化分析和傅里叶红外光谱的部分表征，结果表明该生物表面活性物质为糖脂蛋白。该生物表面活性剂对铜绿假单胞菌PSB2、恶臭假单胞菌PSJ1、沙门氏菌具有较强的杀菌活性。SL2、大肠埃希菌MTCC 118、芽孢杆菌。Bc1和金黄色葡萄球菌STP1的浓度范围为6.4~50 mg/ml。结论：采用响应面方法优化培养基组分和培养条件后，生物表面活性剂的产量提高了4倍。本研究的结果表明，甘蔗糖蜜可以作为一种低成本的底物来提高具有抗菌活性的生物表面活性剂的产量。
Background: Biosurfactants are natural surface-active compounds produced by a variety of microorganisms. The high cost of culture media limits the large-scale production and use of biosurfactants. It is therefore necessary to develop an efficient and cost-effective bioprocess to improve the yield of biosurfactants from microorganisms. In this study, the response surface method was used to optimize the production of biosurfactants by a Lactobacillus strain and the antimicrobial activity of the biosurfactants was assessed.Results: The biosurfactant-producing strain was identified as Lactobacillus paracasei subsp. tolerans N2 after 16S rRNA gene analysis. Among the different variables studied using a Plackett-Burman statistical design, temperature and peptone and sugar cane molasses concentrations were found to be the main factors that had significant (p < 0.05) influence on biosurfactant production. The results of this study showed that molasses concentration at 59.5 g/L, peptone at 6.20 g/L and temperature of 33 degrees C were optimal conditions for biosurfactant production, with a maximum yield of 2.70 g/L. The biosurfactant exhibited surface tension reduction of 37.85 mN/m and antimicrobial activity expressed as inhibition diameter of 63 mm. Partial characterizations by elemental, biochemical and Fourier transmission infrared spectroscopy analysis of the biosurfactant produced revealed that it was glycolipoprotein in nature. The biosurfactant exhibited bactericidal activity against Pseudomonas aeruginosa PSB2, Pseudomonas putida PSJ1, Salmonella sp. SL2, Escherichia coil MTCC 118, Bacillus sp. BC1 and Staphylococcus aureus STP1 at concentrations ranging from 6.4 to 50 mg/mL.Conclusion: The yield of biosurfactant was four-fold higher after optimization of media components and culture conditions using response surface methodology. The results of this study suggested that sugar cane molasses can be used as a low-cost substrate to enhance the yield of biosurfactants with antimicrobial activity.