Red seaweed-based bioprocesses with Corynebacterium glutamicum

The rising population boosts food and energy demand, requiring sustainable solutions. Red seaweed, rich in galactose-based polymers, is a promising feedstock for industrial biotechnology. To enable the industrial workhorse Corynebacterium glutamicum to utilize galactose, the Escherichia coli galactose operon galETKM and galactose permease gene galP were overexpressed as a synthetic operon. After tuning the translational initiation rate of galP, the engineered C. glutamicum strain achieved a growth rate of 0.30 ± 0.01 1/h on 1 % galactose. Further research identified native galactose uptake systems, including the phosphotransferase system components PtsG, PtsF, and the permease IolT2. Next, red seaweed hydrolysate containing galactose, xylose, and glucose was tested as carbon sources, enabling xylose use by expressing xylA from Xanthomonas campestris and endogenous xylB. Additionally, lysine and riboflavin production was achieved at different cultivation scales using engineered C. glutamicum utilizing red seaweed hydrolysate. Hence, this research pioneers red seaweed as microbial feedstock in industrial biotechnology.