氮源对蚜虫拟酵母生物合成新型乳化剂——甘露糖赤藓糖醇脂的影响  

Influence of Nitrogen Sources on a New Emulsifier-Mannosylerythritol Lipids Produced by Pseudozyma aphidis

作　　者：牛永武 吴嘉南 顾頔 陈启和[1] Niu Yongwu;Wu Jianan;Gu Di;Chen Qihe(Department of Food Science and Nutrition, Zhejiang University, Hangzhou 310058)

机构地区：[1]浙江大学食品科学与营养系,杭州310058

出　　处：《中国食品学报》2019年第3期167-174,共8页Journal of Chinese Institute Of Food Science and Technology

基　　金：浙江省科技计划项目公益项目(LGF18C200003)

摘　　要：以蚜虫拟酵母为试验菌株,探究不同氮源对合成甘露糖赤藓糖醇脂(MELs)的影响。选择硝酸钠、酵母提取粉、硫酸铵和硝酸铵为氮源,以MELs产量和生物量为评价指标进行试验,结果发现酵母提取粉最有利于菌体生长,硝酸钠最有利于MELs的合成。针对酵母提取粉和硝酸钠开展复配添加研究,分析发酵过程中生物量、MELs产量、pH、发酵液中还原糖和胞外多糖含量的变化,测定不同组MELs产物在25℃时的临界胶束浓度。结果表明:以添加2.0 g/L硝酸钠和2.0 g/L酵母提取粉为氮源时,发酵后期生物量和MELs产量均为最高,此时最有利于蚜虫拟酵母菌体生长和MELs的合成。分离纯化后的MELs产物临界胶束质量浓度为12.50 mg/L,此时水溶液表面张力降低为(31.45±0.66) mN/m,与其它组产物表面活性无明显差异,说明硝酸钠和酵母提取粉的复配对菌体生长和MELs的合成具有促进作用,合成MELs最高产量达(54.00±1.63) g/L,而对MELs产物的表面活性影响不明显。In this study, the effects of different nitrogen sources on the synthesis of mannosylerythritol lipids(MELs) were investigated by Pseudozyma aphidis. Sodium nitrate, yeast extract, ammonium sulfate and ammonium nitrate were used for tests, according to the MELs yield and biomass, found that yeast extract as nitrogen source is the most conducive to the growth of cell, sodium nitrate is the most conducive to the synthesis of MELs. Then yeast extract and sodium nitrate mixed at different proportion were added, measured the changes of biomass, MELs yield, pH, extracellular reducing sugar and protein concentration during the fermentation process. The critical micelle concentration of MELs product were also determined at 25 ℃. The results showed that when 2.0 g/L sodium nitrate and 2.0 g/L yeast extract were added as nitrogen source, the biomass and MELs yield were the highest at the later stage of fermentation, and the growth of Pseudozyma aphidis and the synthesis of MELs were the best. The critical micelle concentration of the purified MELs was 12.50 mg/L, and the surface tension of the aqueous solution was reduced to(31.45 ± 0.66) mN/m, which showed insignificant difference with the surface activity of MELs from other groups, indicating that the mixture of sodium nitrate and yeast extract had a significant effect on the growth of cell and the yeild of MELs, but not on the surface activity.

关 键 词：甘露糖赤藓糖醇脂 氮源 临界胶束浓度 

分 类 号：TQ423.92[化学工程]