College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China.
Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
Appl Microbiol Biotechnol. 2022 Jan;106(2):713-727. doi: 10.1007/s00253-021-11733-w. Epub 2021 Dec 18.
Recent technical advances regarding filamentous fungi have accelerated the engineering of fungal-based production and benefited basic science. However, challenges still remain and limit the speed of fungal applications. For example, high-throughput technologies tailored to filamentous fungi are not yet commonly available for genetic modification. The currently used fungal genetic manipulations are time-consuming and laborious. Here, we developed a flow cytometry-based plating-free system to directly screen and isolate the transformed protoplasts in industrial fungi Myceliophthora thermophila and Aspergillus niger. This system combines genetic engineering via the 2A peptide and the CRISPR-Cas9 system, strain screening by flow cytometry, and direct sorting of colonies for deep-well-plate incubation and phenotypic analysis while avoiding culturing transformed protoplasts in plates, colony picking, conidiation, and cultivation. As a proof of concept, we successfully applied this system to generate the glucoamylase-hyperproducing strains MtYM6 and AnLM3 in M. thermophila and A. niger, respectively. Notably, the protein secretion level and enzyme activities in MtYM6 were 17.3- and 25.1-fold higher than in the host strain. Overall, these findings suggest that the flow cytometry-based plating-free system can be a convenient and efficient tool for strain engineering in fungal biotechnology. We expect this system to facilitate improvements of filamentous fungal strains for industrial applications. KEY POINTS: • Development of a flow cytometry-based plating-free (FCPF) system is presented. • Application of FCPF system in M. thermophila and A. niger for glucoamylase platform. • Hyper-produced strains MtYM6 and AnLM3 for glucoamylase production are generated.
近年来,有关丝状真菌的技术进步加速了真菌生产的工程化,并有益于基础科学。然而,挑战仍然存在,限制了真菌应用的速度。例如,针对丝状真菌的高通量技术尚未广泛用于遗传修饰。目前使用的真菌遗传操作既耗时又费力。在这里,我们开发了一种基于流式细胞术的无平板系统,可直接筛选和分离工业真菌嗜热毁丝霉(Myceliophthora thermophila)和黑曲霉(Aspergillus niger)中的转化原生质体。该系统结合了 2A 肽的基因工程和 CRISPR-Cas9 系统、流式细胞术的菌株筛选,以及直接对菌落进行分类,用于深孔板孵育和表型分析,同时避免在平板中培养转化的原生质体、菌落挑取、产孢和培养。作为概念验证,我们成功地将该系统应用于分别在嗜热毁丝霉和黑曲霉中生成了葡糖淀粉酶高产菌株 MtYM6 和 AnLM3。值得注意的是,MtYM6 的蛋白分泌水平和酶活性分别比宿主菌株高 17.3 倍和 25.1 倍。总体而言,这些发现表明,基于流式细胞术的无平板系统可以成为真菌生物技术中菌株工程的一种便捷、高效的工具。我们期望该系统能够促进丝状真菌菌株的改进,以满足工业应用的需求。
• 介绍了一种基于流式细胞术的无平板(FCPF)系统的开发。
• 在嗜热毁丝霉和黑曲霉中应用 FCPF 系统构建葡糖淀粉酶平台。
• 生成了用于葡糖淀粉酶生产的高表达菌株 MtYM6 和 AnLM3。