Ivušić Franjo, Šantek Božidar
Croatian Academy of Sciences and Arts, The Institute for Corrosion Research and Desalinization, Vlaha Bukovca 14, 20000, Dubrovnik, Croatia.
Bioprocess Biosyst Eng. 2015 Jun;38(6):1103-12. doi: 10.1007/s00449-015-1353-3. Epub 2015 Jan 20.
Heterotrophic cultivation of Euglena gracilis was carried out on synthetic (Hutner medium) and complex cultivation media in order to optimize production of β-1,3-glucan (paramylon). For preparation of complex media, various industrial by-products (e.g., molasses, corn steep solid, yeast extract, and beef extract) were used with or without addition of pure compounds [glucose, galactose, fructose, lactose, maltose, sucrose, and (NH4)2HPO4]. Heterotrophic cultivation of E. gracilis was performed in Erlenmeyer flasks and additionally confirmed during research in the stirred tank bioreactor. The results clearly show that E. gracilis can easily metabolize glucose and fructose as carbon sources and corn steep solid as complex nitrogen and growth factors source for biomass growth and paramylon synthesis. Furthermore, it was also proved that addition of (NH4)2HPO4, beef extract, or gibberellic acid did not have positive effect on the biomass growth and paramylon synthesis. After optimization of complex medium composition and verification in the stirred tank bioreactor, it was concluded that medium composed of glucose (20 g/L) and corn steep solid (30 g/L) is the most suitable complex medium for industrial cultivation of E. gracilis and paramylon production.
为了优化β-1,3-葡聚糖（副淀粉）的生产，在合成培养基（胡特纳培养基）和复合培养基上进行了纤细裸藻的异养培养。为了制备复合培养基，使用了各种工业副产品（如糖蜜、玉米浆固体、酵母提取物和牛肉提取物），添加或不添加纯化合物[葡萄糖、半乳糖、果糖、乳糖、麦芽糖、蔗糖和磷酸氢二铵]。纤细裸藻的异养培养在锥形瓶中进行，并在搅拌罐生物反应器的研究中得到进一步证实。结果清楚地表明，纤细裸藻能够轻易地将葡萄糖和果糖作为碳源进行代谢，并将玉米浆固体作为复合氮源和生长因子源用于生物量生长和副淀粉合成。此外，还证明添加磷酸氢二铵、牛肉提取物或赤霉素对生物量生长和副淀粉合成没有积极影响。在优化复合培养基组成并在搅拌罐生物反应器中进行验证后，得出结论：由葡萄糖（20 g/L）和玉米浆固体（30 g/L）组成的培养基是用于纤细裸藻工业培养和副淀粉生产的最合适复合培养基。
