PDF(Pubmed)
Abstract：
Polyol lipids (a.k.a. liamocins) produced by the polyextremotolerant, yeast-like fungus Aureobasidium pullulans are amphiphilic molecules with high potential to serve as biosurfactants. So far, cultivations of A. pullulans have been performed in media with complex components, which complicates further process optimization due to their undefined composition. In this study, we developed and optimized a minimal medium, focusing on biosurfactant production. Firstly, we replaced yeast extract and peptone in the best-performing polyol lipid production medium to date with a vitamin solution, a trace-element solution, and a nitrogen source. We employed a design of experiments approach with a factor screening using a two-level-factorial design, followed by a central composite design. The polyol lipid titer was increased by 56% to 48 g L-1, and the space-time yield from 0.13 to 0.20 g L-1 h-1 in microtiter plate cultivations. This was followed by a successful transfer to a 1 L bioreactor, reaching a polyol lipid concentration of 41 g L-1. The final minimal medium allows the investigation of alternative carbon sources and the metabolic pathways involved, to pinpoint targets for genetic modifications. The results are discussed in the context of the industrial applicability of this robust and versatile fungus.
摘要：
多倍耐受性产生的多元醇脂质（又名，g），酵母样真菌金黄色葡萄球菌是两亲性分子，具有很高的生物表面活性剂潜力。到目前为止,支链淀粉的培养已经在具有复杂成分的培养基中进行，由于其组成不明确，这使得进一步的工艺优化变得复杂。在这项研究中,我们开发并优化了一种最低限度的培养基，专注于生物表面活性剂的生产。首先,我们用维生素溶液代替了迄今为止性能最好的多元醇脂质生产培养基中的酵母提取物和蛋白胨，微量元素解决方案，和氮源。我们采用了一种实验设计方法，使用两级因子设计进行因子筛选，其次是中央复合设计。在微量滴定板培养中，多元醇脂质滴度增加了56％，达到48gL-1，时空产量从0.13增加到0.20gL-1h-1。随后成功转移到1升生物反应器中，达到41gL-1的多元醇脂质浓度。最终的基本培养基允许研究替代碳源和所涉及的代谢途径，确定遗传修饰的目标。在这种强大而通用的真菌的工业适用性的背景下讨论了结果。
