Engineered E. coli convert kimchi radish waste into biodegradable bioplastic

Every year, approximately 132,000 metric tons of radish waste are generated during kimchi production in South Korea. Currently, about 94% of this by-product waste is discarded as food waste or sent to waste treatment facilities, causing environmental harm and disposal costs. Researchers at the World Institute of Kimchi (WiKim) have developed a strategy to convert these agricultural by-products into biodegradable bioplastics using engineered Escherichia coli.

The study, published in Bioresource Technology, utilized a genome-scale model-guided microbial engineering approach. This involved transcriptomic analysis combined with a transcriptome-constrained genome-scale metabolic model (GEM) to identify targets for metabolic engineering. Unlike traditional trial-and-error methods, this approach predicts genetic modifications that redirect metabolic flux toward bioplastic production, providing a new method for agricultural waste valorization and sustainable biomanufacturing.

The team started by enzymatically converting radish by-products into radish hydrolyzate, which was then used as the sole feedstock for engineered E. coli to produce poly(3-hydroxybutyrate) (P(3HB)), a biodegradable bioplastic. P(3HB) accounted for 71.95% of the dry cell weight of the engineered strain, a 78% increase compared to the parental strain.

In fed-batch fermentation, the final P(3HB) concentration reached 5.75 g/L, with the polymer making up 75.60% of the dry cell weight. This demonstrates the feasibility of converting agricultural waste into biodegradable plastics through scalable microbial bioprocessing.