posted on 2024-01-23, 18:43authored byLei Zhou, Yufei Zhang, Tingting Chen, Junhua Yun, Mei Zhao, Hossain M. Zabed, Cunsheng Zhang, Xianghui Qi
Embracing the principles of sustainable
development,
the valorization of agrowastes into value-added chemicals has nowadays
received significant attention worldwide. Herein, Escherichia
coli was metabolically rewired to convert cellulosic
hydrolysate of corn stover into a key platform chemical, namely, 3-hydroxypropionic
acid (3-HP). First, the heterologous pathways were introduced into E. coli by coexpressing glycerol-3-P dehydrogenase
and glycerol-3-P phosphatase in both single and fusion (gpdp12) forms, making the strain capable of synthesizing glycerol from
glucose. Subsequently, a glycerol dehydratase (DhaB123-gdrAB) and
an aldehyde dehydrogenase (GabD4) were overexpressed to convert glycerol
into 3-HP. A fine-tuning between glycerol synthesis and its conversion
into 3-HP was successfully established by 5′-untranslated region
engineering of gpdp12 and dhaB123-gdrAB. The strain was further metabolically modulated to
successfully prevent glycerol flux outside the cell and into the central
metabolism. The finally remodulated chassis produced 32.91 g/L 3-HP
from the cellulosic hydrolysate of stover during fed-batch fermentation.