利用酵母 Meyerozyma guilliermondii YK32 生产生物表面活性剂的工艺参数。
Process parameters for biosurfactant production using yeast Meyerozyma guilliermondii YK32.
机构信息
Department of Microbiology, CCS Haryana Agricultural University, Hisar, 125004, India.
出版信息
Environ Monit Assess. 2019 Aug 2;191(9):531. doi: 10.1007/s10661-019-7665-z.
Microbially produced biosurfactants are fast catching up due to their environment-friendly approach over chemical surfactants. But their commercial production is restricted due to poor economy of the production process which could be improved by using high yielding microbial strains and optimizing the process parameters. The present research was directed to optimize the biosurfactant production monitored in terms of oil displacement and emulsification (E) index, using a promising yeast Meyerozyma guilliermondii YK32. Maximum oil displacement equaling 7.5 cm was obtained with olive oil at 8% (v/v) concentration as carbon source under shaking conditions (150 rpm). Diesel being a complex hydrocarbon was not utilized easily by yeast and showed poor biosurfactant production. Yeast extract at 1.5% (w/v) concentration yielded maximum biosurfactant as evident from maximum oil displacement and E index equal to 8.1 cm and 52.6%, respectively. Sodium chloride at the rate of 3% (w/v) supported maximum oil displacement (8.8 cm) using the production broth containing optimized carbon and nitrogen sources. Any increase beyond this level negatively influenced the biosurfactant production. The yield was at its maximum at 30 °C as a shift in temperature either to 35 °C or 25 °C decreased the oil displacement from 8.8 to 5.2 or 7.6 cm, respectively. At 40 °C, oil displacement was decreased to 2.5 cm. Biosurfactant production appeared to be sensitive to varying pH as evident from the E index as high as 67.3% at pH 6.0 as compared with 60.2%, 60.1%, and 52.4% at pH 5.0, 5.5, and 7.0, respectively. Yeast biomass yield equivalent to 10.3 g/L and 8.3 g/L was recorded at pH 6 and 7, respectively, during the production process. Elimination of shaking reduced the E index from 67.3 to 34.8% under optimized conditions.
微生物产生的生物表面活性剂由于其比化学表面活性剂更环保的方法而迅速普及。但是，由于生产过程的经济性较差，其商业生产受到限制，这可以通过使用高产微生物菌株和优化工艺参数来改善。本研究旨在使用有前途的酵母 Meyerozyma guilliermondii YK32 优化生物表面活性剂的生产，监测其在驱油和乳化（E）指数方面的表现。在摇床条件下（150 rpm），以 8%（v/v）浓度的橄榄油作为碳源，可获得最大的驱油能力 7.5 cm。柴油作为一种复杂的碳氢化合物，不易被酵母利用，生物表面活性剂产量也较差。酵母提取物在 1.5%（w/v）浓度下，从最大的驱油能力和 E 指数分别为 8.1 cm 和 52.6%，可以得到最大的生物表面活性剂产量。在含有优化的碳氮源的生产培养液中，添加 3%（w/v）的氯化钠可获得最大的驱油能力（8.8 cm）。超过这个水平的任何增加都会对生物表面活性剂的生产产生负面影响。在 30°C 时产量达到最大值，当温度分别升高到 35°C 或降低到 25°C 时，驱油能力分别从 8.8 cm 降低到 5.2 cm 或 7.6 cm。在 40°C 时，驱油能力降低到 2.5 cm。生物表面活性剂的生产似乎对 pH 值的变化很敏感，从 E 指数可以看出，在 pH 值为 6.0 时，E 指数高达 67.3%，而在 pH 值为 5.0、5.5 和 7.0 时，E 指数分别为 60.2%、60.1%和 52.4%。在生产过程中，在 pH 值为 6 和 7 时，酵母生物量产量分别为 10.3 g/L 和 8.3 g/L。在优化条件下，消除摇床会使 E 指数从 67.3%降低到 34.8%。
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