Itaconic acid is an unsaturated, dicarboxylic acid which finds a wide range of applications in the polymer industry and as a building block for fuels, solvents and pharmaceuticals. Currently, Aspergillus terreus is used for industrial production, with titers above 100 g L−1 depending on the conditions. Besides A. terreus, Ustilago maydis is also a promising itaconic acid production host due to its yeast-like morphology. Recent strain engineering efforts significantly increased the yield, titer and rate of production. In this study, itaconate production by U. maydis was further increased by integrated strain- and process engineering. Next-generation itaconate hyper-producing strains were generated using CRISPR/Cas9 and FLP/FRT genome editing tools for gene deletion, promoter replacement, and overexpression of genes. The handling and morphology of this engineered strain were improved by deletion of fuz7, which is part of a regulatory cascade that governs morphology and pathogenicity. These strain modifications enabled the development of an efficient fermentation process with in situ product crystallization with CaCO3. This integrated approach resulted in a maximum itaconate titer of 220 g L−1, with a total acid titer of 248 g L−1, which is a significant improvement compared to best published itaconate titers reached with U. maydis and with A. terreus. In this study, itaconic acid production could be enhanced significantly by morphological- and metabolic engineering in combination with process development, yielding the highest titer reported with any microorganism.

中文翻译：

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集成的菌株和工艺设计可利用玉米黑粉菌生产 220 g L−1 衣康酸

衣康酸是一种不饱和二羧酸，在聚合物工业中有着广泛的应用，并可作为燃料、溶剂和药品的基础材料。目前，土曲霉已用于工业生产，根据条件滴度可达100 g L−1以上。除土曲霉外，玉米黑粉菌因其类似酵母的形态也是一种有前途的衣康酸生产宿主。最近的菌株工程工作显着提高了产量、滴度和生产率。在这项研究中，通过整合菌株和工艺工程，进一步提高了玉米衣康酸产量。使用 CRISPR/Cas9 和 FLP/FRT 基因组编辑工具进行基因删除、启动子替换和基因过表达，生成了下一代衣康酸高产菌株。通过删除fuz7，该工程菌株的处理和形态得到了改善，fuz7是控制形态和致病性的调控级联的一部分。这些菌株修饰使得能够开发出一种高效的发酵工艺，并使用 CaCO3 进行原位产物结晶。这种综合方法导致最大衣康酸滴度为 220 g L−1，总酸滴度为 248 g L−1，与已发表的玉米 U. 玉米和 A. terreus 达到的最佳衣康酸滴度相比，这是一个显着的改进。在这项研究中，通过形态学和代谢工程与工艺开发相结合，可以显着提高衣康酸的产量，从而产生任何微生物所报道的最高滴度。