Enhancing single-cell hyaluronic acid biosynthesis by microbial morphology engineering

• Published in: Synthetic and systems biotechnology Vol. 5; no. 4; pp. 316 - 323
• Main Authors: Zheng, Yukun, Cheng, Fangyu, Zheng, Bo, Yu, Huimin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2020; KeAi Publishing; KeAi Communications Co., Ltd
• Subjects: DivIVA protein; Down/up dual regulation; Enlarged cells; FtsZ protein; Morphology engineering; Single-cell HA-Producing capacity; Morphology engineering; DivIVA protein; FtsZ protein; Down/up dual regulation; Enlarged cells; Single-cell HA-Producing capacity
• ISSN: 2405-805X; 2405-805X
• DOI: 10.1016/j.synbio.2020.09.002

Microbial morphology engineering is a novel approach for cell factory to improve the titer of target product in bio-manufacture. Hyaluronic acid (HA), a valuable glycosaminoglycan polymerized by HA synthase (HAS), a membrane protein, is particularly selected as the model product to improve its single-cell HA-producing capacity via morphology engineering. DivIVA and FtsZ, the cell-elongation and cell division related protein, respectively, were both down/up dual regulated in C. glutamicum via weak promoter substitution or plasmid overexpression. Different from the natural short-rod shape, varied morphologies of engineered cells, i.e. small-ellipsoid-like (DivIVA-reduced), bulb-like (DivIVA-enhanced), long-rod (FtsZ-reduced) and dumbbell-like (FtsZ-enhanced), were observed. Applying these morphology-changed cells as hosts for HA production, the reduced expression of both DivIVA and FtsZ seriously inhibited normal cell growth; meanwhile, overexpression of DivIVA didn't show morphology changes, but overexpression of FtsZ surprisingly change the cell-shape into long and thick rod with remarkably enlarged single-cell surface area (more than 5.2-fold-increase). And finally, the single-cell HA-producing capacity of the FtsZ-overexpressed C. glutamicum was immensely improved by 13.5-folds. Flow cytometry analyses verified that the single-cell HAS amount on membrane was enhanced by 2.1 folds. This work is pretty valuable for high titer synthesis of diverse metabolic products with microbial cell factory.