Embrapa Hortaliças , Brasília, DF , Brasil.
Braz J Microbiol. 2012 Jan;43(1):109-15. doi: 10.1590/S1517-838220120001000012. Epub 2012 Jun 1.
Sequential statistical methods were used to maximise carotenoid production by a strain of Rhodotorula mucilaginosa, isolated from the Brazilian ecosystem. Initially, a factorial 2(5-1) experimental design was used, and the variables were pH and the levels of glucose, yeast extract, MgSO4.7H2O and KH2PO4. The nitrogen source (yeast extract) was the most important variable in enhancing carotenoid production; MgSO4.7H2O and KH2PO4 had a negative influence. The initial pH had no significant effect on carotenoid and cell productions. We further investigated the effects of glucose and yeast extract effects, using a second-order central composite design (CCD) to optimise carotenoid production, which was adequately approximated with a full quadratic equation obtained from a two-factor-2-level design. The analysis of quadratic surfaces showed that after 5 days of cultivation at 25 °C, the maximum carotenoid concentration (745 µg l(-1)) was obtained with 15 g l(-1) of yeast extract and 20 g l(-1) of glucose. The maximum carotenoid production (152 µg g(-1)) was obtained with 5 g l(-1) yeast extract and 10 g l(-1) glucose. Carotenoid formation was more sensitive to changes in yeast extract concentration than to changes in glucose concentration. Maximum cell production was achieved with 15-17 g l(-1) of yeast extract and 15-20 g l(-1) of glucose.
采用序贯统计方法最大限度地提高了从巴西生态系统中分离出的粘红酵母（Rhodotorula mucilaginosa）菌株的类胡萝卜素产量。最初，使用了析因 2(5-1)实验设计，变量为 pH 值以及葡萄糖、酵母提取物、MgSO4.7H2O 和 KH2PO4 的水平。氮源（酵母提取物）是提高类胡萝卜素产量的最重要变量；MgSO4.7H2O 和 KH2PO4 有负面影响。初始 pH 值对类胡萝卜素和细胞产量没有显著影响。我们进一步研究了葡萄糖和酵母提取物的影响，使用二阶中心组合设计（CCD）来优化类胡萝卜素的生产，这可以通过从两因素两水平设计获得的全二次方程进行充分近似。二次曲面分析表明，在 25°C 下培养 5 天后，当酵母提取物浓度为 15 g l(-1)，葡萄糖浓度为 20 g l(-1)时，可获得最大类胡萝卜素浓度（745 µg l(-1)）。当酵母提取物浓度为 5 g l(-1)，葡萄糖浓度为 10 g l(-1)时，可获得最大类胡萝卜素产量（152 µg g(-1)）。类胡萝卜素的形成对酵母提取物浓度的变化比对葡萄糖浓度的变化更为敏感。最大细胞产量是在 15-17 g l(-1)酵母提取物和 15-20 g l(-1)葡萄糖浓度下实现的。
