Isolation and characterization of solventogenic, cellulase-free xylanolytic Clostridia from cow rumen

Abstract

Hemicellulolytic obligate anaerobes capable of converting a range of agricultural substrates and monomeric sugars of hemicellulose to solvents and acids were isolated from cow rumen fluid. The strains were identified as 5 strains of C. beijerinckii (3 different genotypes), 3 strains of C. acetobutylicum (2 different genotypes), 1 strain of C. butyricum and 3 strains of C. bifermentans (2 different genotypes). All of them produced cellulase-free xylanase activity. C. acetobutylicum LU1 produced solvent, a high of 5.1 gl(-1) and C.bifermentans LU1 produced xylanase activity a high of 4.2 IU ml(-1).

Horizontal gene transfer from Bacteria to rumen Ciliates indicates adaptation to their anaerobic, carbohydrates-rich environment

“…Nevertheless, we also found a substantial number of ESTs with a bacterial Best Hit. The Bacterium with the most Best Hits is Clostridiumacetobutylicum , a Firmicute which has previously been isolated from bovine rumen fluid [ 17 ]. A total of 11 different Firmicutes were identified with Best Hits, plus nine "other" Bacteria and two Archaea species.…”

One-pot fermentation of agricultural residues to produce butanol and hydrogen by Clostridium strain BOH3

“…In literature, some solventogenic Clostridium strains, such as C. beijerinckii NCIMB 8052 and IBUN 125C, and C. acetobutylicum IBUN 13A and 18A, expressed multiple saccharolytic enzymes including cellulase, xylanase and amylase [14]. Similarly, a few other Clostridium strains such as C. beijerinckii LU-1 and Clostridium bifermentans LU-1 were reported to express xylanase [15]. Recently, we also reported that a Clostridium strain BOH3 expressed both xylanase and amylase during fermentation [16,17].…”

Current progress on engineering microbial strains and consortia for production of cellulosic butanol through consolidated bioprocessing

“…Lignocellulose is significantly more recalcitrant to biodegradation than traditional ABE fermentation feedstocks. The four main native butanol producers, C. acetobutylicum , Clostridium beijerinckii , Clostridium saccharobutylicum , and Clostridium saccharoperbutylacetonicum (Gu et al, 2011 , 2014 ), cannot directly grow on lignocellulose (Lee et al, 1985 ; Levi Hevroni et al, 2020 ; Sabathé et al, 2002 ; Sankar et al, 2003 ). Therefore, inefficient multistep processes are required for fermenting lignocellulose to butanol which features biomass pre‐treatment and/or dedicated cellulase production and/or separated biomass saccharification and/or hexose and/or pentose fermentation (Figure 1 ) (Mazzoli, 2020 ; Tarraran & Mazzoli, 2018 ).…”