Clostridium ljungdahlii represents a microbial production platform based on syngas

Abstract

Clostridium ljungdahlii is an anaerobic homoacetogen, able to ferment sugars, other organic compounds, or CO 2 /H 2 and synthesis gas (CO/H 2 ). The latter feature makes it an interesting microbe for the biotech industry, as important bulk chemicals and proteins can be produced at the expense of CO 2 , thus combining industrial needs with sustained reduction of CO and CO 2 in the atmosphere. Sequencing the complete genome of C. ljungdahlii revealed that it comprises 4,630,065 bp and is one of the largest clostridial genomes known to date. Experimental data and in silico comparisons revealed a third mode of anaerobic homoacetogenic metabolism. Unlike other organisms such as Moorella thermoacetica or Acetobacterium woodii , neither cytochromes nor sodium ions are involved in energy generation. Instead, an Rnf system is present, by which proton translocation can be performed. An electroporation procedure has been developed to transform the organism with plasmids bearing heterologous genes for butanol production. Successful expression of these genes could be demonstrated, leading to formation of the biofuel. Thus, C. ljungdahlii can be used as a unique microbial production platform based on synthesis gas and carbon dioxide/hydrogen mixtures.

Trash to treasure: production of biofuels and commodity chemicals via syngas fermenting microorganisms

“…On the methyl branch, a sixelectron reduction of CO 2 yields a methyl moiety while the carbonyl branch reduces CO 2 to CO which is bound to Syngas fermentation for production of organic compounds Latif et al 81 The Wood-Ljungdahl pathway and its connection to heterotrophic metabolism. Shown is the WL pathway for Clostridium ljungdahlii as assessed in [21,22] with reduced ferredoxin, NADH, and NADPH serving as electron carriers during CO 2 fixation. The left panel shows the Methyl and Carbonyl branches of the WL pathway leading to either acetate formation or assimilation of acetyl-CoA into biomass.…”

Production of Acetate from Carbon Dioxide in Bioelectrochemical Systems Based on Autotrophic Mixed Culture

“…The reduction of carbon dioxide in BESs may be a promising way to simultaneously reduce carbon dioxide emissions and generate fuels or other organic compounds [3,9,11,13,18,19,28], which is significant in terms of the environment, energy, and resources.…”

BIOHYDROGEN FROM CHEESE WHEY TREATMENT IN AN AnSBBR: ACHIEVING PROCESS STABILITY

“…Among these Clostridium ljungdahlii (Tanner et al, 1993;Köpke et al, 2010) and Clostridium carboxidivorans (Liou et al, 2005) should be mentioned, which are capable of growing heterotrophically in sugars (hexoses and pentoses) or autotrophically (Wood-Ljungdahl pathway) in gases (CO or CO 2 + H 2 ). As previously mentioned, hydrogen is an intermediate product in several biological processes and may be consumed in the liquid medium, thus requiring inhibition of this consumption.…”