响应面法优化德氏乳杆菌保加利亚亚种NCFB2772发酵生产胞外多糖的培养条件优化

Employing Response Surface Methodology to Optimize Culture Conditions for Extracellular Polysaccharide Production by Lactobacillus delbrueckii subsp.bulgaricus NCFB2772

在单因素试验的基础上,采用响应面分析法,优化初始pH值、接种量、发酵温度3个主要培养条件对徳氏乳杆菌保加利亚亚种NCFB2772(Lactobacillus delbrueckii subsp.bulgaricus NCFB2772,L.b NCFB2772)高产乳酸菌胞外多糖(extracellular polysaccharides,EPS)的影响。结果表明,初始pH6.5、接种量4.5%、发酵温度42℃、L.b NCFB2772合成EPS的量达到最大(907.8mg/L)。各因素对响应值的影响可用回归方程Y=-287.08+39.83C1+11.44C2+18.54C3表示。

Extracellular polysaccharide （EPS） and strategies for improving ESP yield and functionality are always a hot topic that has received much attention in the academic world. In this study, response surface methodology was employed to optimize the culture conditions for EPS production by Lactobacillus delbrueckii subsp.bulgaricus NCFB2772 in MRS medium. Based on one-factor-at-a-time experiments, a 6-factor, 2-level Plackett-Burman factional design was performed to identify initial medium pH （C1）, inoculum size （C2） and culture temperature （C3） as main factors that affect EPS production （Y）. Further, the selected cuRure conditions were optimized for achieving maximum EPS production using response surface methodology based on a 3- factor, 3-level central composite design. It was found that initial medium pH 6.5 and 4.5% inoculum size for fermentation at 42 ℃ provided maximum EPS production （907.8 mg/L）. A regression model was built as follows： Y= - 287.08 ＋ 39.83C1 ＋ 11.44C2 ＋ 18.54C3. This study has the potential to provide references for improved industrial EPS production from Lactobacillus delbruecldi subsp.bulgaricus NCFB2772.