Cofactor engineering in Thermoanaerobacterium aotearoense SCUT27 for maximizing ethanol yield and revealing an enzyme complex with high ferredoxin-NAD+ reductase activity.
Bioresour Technol
; 402: 130784, 2024 Jun.
Article
in En
| MEDLINE
| ID: mdl-38701976
ABSTRACT
Thermoanaerobacterium aotearoense SCUT27 is a prominent producer of biofuels from lignocellulosic materials. To provide sufficient NAD(P)H for ethanol production, redox-related genes, including lactate dehydrogenase (ldh), redox-sensing transcriptional repressor (rex), and hydrogenase (hfsB), were knocked out. However, the growth of strain PRH (Δldh/Δrex/ΔhfsB) was suppressed due to the intracellular redox state imbalance with the increased NADH concentration. Coincidentally, when the Bcd-EtfAB (BCD) complex was overexpressed, the resulting strain PRH-B3 (Δldh/Δrex/ΔhfsBBCD) grew rapidly and produced ethanol with a high yield. With lignocellulosic hydrolysates, PRH-BA (Δldh/Δrex/ΔhfsBBCDadhE) demonstrated high ethanol productivity and yield, reaching levels of 0.45-0.51 g/L/h and 0.46-0.53 g/g sugars, respectively. The study results shed light on the cofactor balance for cell stability and the high ferredoxin-NAD+ reductase activity of the BCD complex under an intracellular low redox state. They also provide an essential reference for developing strains for improved biofuel production.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Thermoanaerobacterium
/
Ethanol
Language:
En
Journal:
Bioresour Technol
Journal subject:
ENGENHARIA BIOMEDICA
Year:
2024
Document type:
Article
Affiliation country:
China
Country of publication:
United kingdom