响应面法优化制备高富硒产朊假丝酵母

Optimization of Selenium-enriched Candida utilis by Response Surface Methodology

考察了发酵条件对产朊假丝酵母富硒能力的影响。通过单因素的筛选,对酵母富硒能力影响较大的3个因素:亚硒酸钠浓度、初始p H值及培养温度,以胞内总硒含量为响应值,利用响应面法对其进行优化。结果显示:在培养时间30 h、加硒时间对数生长中期、亚硒酸钠浓度35 mg·L-1,初始p H 6.6、接种量10%、培养温度27℃、装液量150 m L/500 m L的条件下,最大的菌体生物量为6.87 g·L-1;胞内总硒含量达到12 639.7μg·L-1,硒含量为1 839.8μg·g-1,其中亚硒酸钠转化率为79.1%,有机硒含量占90%以上;胞内实际总硒含量与数学模型理论值12 518.8μg·L-1相差不显著,响应面法能较好地优化产朊假丝酵母富硒工艺条件。

The fermentation conditions of selenium enrichment by Candida utilis were studied. Based on the results of the single factor experiment, three factors including the concentration of sodium selenite, inital pH and incubation temperature were selected. The response surface method was used to optimize the various factors. The optimal conditions were obtained as follows：incubation time was 30 h, time of adding selenium was mid-logarithmic, the sodium selenite concentration was 35 mg·L^-1 with inital pH of 6.6, incubation concentration of 10%, incubation temperature of 27℃, the medium volume of 150 mL/500 mL, respectively. Under the optimal condition, the biomass was 6.87 g·L^-1. The total selenium content of Candida utilis was 12 639.7μg·L^-1, and the selenium content of the cells was 1 839.8μg·g^-1, in which sodium selenite conversion rate was 79.1%and the organic selenium was higher than 90%. The actual value of selenium content was substantially consistent with the theoretical value, and the response surface methodology was applicable for the fermentation conditions of selenium enriched by Candida utilis.