Fan_2026_J.Biotechnol__

The utilization of edible biomass as feedstocks poses sustainability concerns, prompting the exploration of affordable alternative carbon sources. Acetate is a promising candidate due to its high availability and low cost. This study developed an engineered platform for the secretory production of the cutinase ICCG-A2 in Corynebacterium glutamicum using high-concentration acetate as the sole carbon source. When cultured on sodium acetate (equimolar carbon content relative to glucose) as the sole carbon source, the engineered strain showed 0.67-fold maximum cell density but slightly higher extracellular enzyme activity (1.17-fold) relative to glucose. Next, combinatorial optimization of signal peptides and promoters identified the WapA-P(A256) pair as optimal, boosting the per-OD(600) specific enzyme activity to 2.57-fold relative to the control. Co-expressing the cgl2496 and acs gene enhanced acetate tolerance and assimilation, shortening fermentation time by approximately 25% and raising per-OD(600) specific enzyme activity to 1.71-fold relative to the starting strain in strain Cg-ACE, despite minor growth impairment. Medium optimization (C/N ratio and ions) alleviated this defect, increasing maximum cell density and extracellular enzyme activity to 1.25-fold and 1.72-fold relative to the initial medium. Scale-up to 1-L flasks further improved performance: extracellular enzyme activity reached 2.02-fold versus 125-mL flasks and 4.27-fold versus glucose. This work provides a systematic strategy for acetate-based biomanufacturing, supporting efficient conversion of acetate to high-value biochemicals.