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Impact of syringaldehyde on the growth of Clostridium beijerinckii NCIMB 8052 and butanol production

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ABSTRACT

While lignocellulosic biomass excels as a cheap, renewable resource for biofuel production, it does present some challenges such as generation of microbial inhibitory compounds. The mode of selective inhibition of acetone–butanol–ethanol (ABE) production (as opposed to cell growth) by syringaldehyde on Clostridium beijerinckii NCIMB 8052 was examined. C. beijerinckii 8052 grown in syringaldehyde-supplemented P2 medium had a comparable growth rate (μ = 0.34) at acidogenic growth phase to that of C. beijerinckii 8052 grown in control P2 medium (μ = 0.30). The addition of syringaldehyde into P2 medium inhibited solvent production by C. beijerinckii 8052 and increased butyric and acetic acid accumulation in the fermentation broth. Analysis of coenzyme A transferase (CoAT) using cell-free extracts of C. beijerinckii 8052 showed decreased expression and activity in the presence of syringaldehyde. These results indicate that C. beijerinckii 8052 CoAT is negatively affected by syringaldehyde and thus, hampers the ability of the microorganism to metabolize butyric and acetic acid for ABE production as evidenced by the accumulation of butyric and acetic acid in the fermentation broth.

No MeSH data available.


Butanol and total ABE production by C. beijerinckii grown in P2 medium and syringaldehyde-supplemented P2 medium. SA with broken lines represents concentration of syringaldehyde during the course of fermentation. Butanol_CTL and ABE_CTL represent butanol and total ABE production by C. beijerinckii grown in P2 medium. Butanol_SA and ABE_SA represent butanol and total ABE production by C. beijerinckii grown in syringaldehyde-supplemented P2 medium. Data represent averages of results from at least three fermentations
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Fig4: Butanol and total ABE production by C. beijerinckii grown in P2 medium and syringaldehyde-supplemented P2 medium. SA with broken lines represents concentration of syringaldehyde during the course of fermentation. Butanol_CTL and ABE_CTL represent butanol and total ABE production by C. beijerinckii grown in P2 medium. Butanol_SA and ABE_SA represent butanol and total ABE production by C. beijerinckii grown in syringaldehyde-supplemented P2 medium. Data represent averages of results from at least three fermentations

Mentions: Cofactors (NADH and NADPH) are involved in the detoxification of aldehydes by microorganisms (Miller et al. 2009). These cofactors are also involved in butanol synthesis and play vital role during transition from acidogenesis to solventogenesis (Grupe and Gottschalk 1992). It is conceivable that NADH and NADPH pools did not reach levels required for sustenance of glycolysis due to diversion to syringaldehyde detoxification, resulting in inability of C. beijerinckii to transition from acidogenesis to solventogenesis (Zhang et al. 2011). To test this hypothesis, syringaldehyde concentration in the syringaldehyde-supplemented P2 fermentation medium was analyzed. Figure 4 indicates that C. beijerinckii cells grown in syringaldehyde-supplemented P2 medium did not metabolize syringaldehyde but butanol production was negatively affected. Therefore, the failure of C. beijerinckii to transition from acidogenic to solventogenic phase was not as a result of depletion of cofactors pool due to syringaldehyde detoxification.Fig. 4


Impact of syringaldehyde on the growth of Clostridium beijerinckii NCIMB 8052 and butanol production
Butanol and total ABE production by C. beijerinckii grown in P2 medium and syringaldehyde-supplemented P2 medium. SA with broken lines represents concentration of syringaldehyde during the course of fermentation. Butanol_CTL and ABE_CTL represent butanol and total ABE production by C. beijerinckii grown in P2 medium. Butanol_SA and ABE_SA represent butanol and total ABE production by C. beijerinckii grown in syringaldehyde-supplemented P2 medium. Data represent averages of results from at least three fermentations
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Related In: Results  -  Collection

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Fig4: Butanol and total ABE production by C. beijerinckii grown in P2 medium and syringaldehyde-supplemented P2 medium. SA with broken lines represents concentration of syringaldehyde during the course of fermentation. Butanol_CTL and ABE_CTL represent butanol and total ABE production by C. beijerinckii grown in P2 medium. Butanol_SA and ABE_SA represent butanol and total ABE production by C. beijerinckii grown in syringaldehyde-supplemented P2 medium. Data represent averages of results from at least three fermentations
Mentions: Cofactors (NADH and NADPH) are involved in the detoxification of aldehydes by microorganisms (Miller et al. 2009). These cofactors are also involved in butanol synthesis and play vital role during transition from acidogenesis to solventogenesis (Grupe and Gottschalk 1992). It is conceivable that NADH and NADPH pools did not reach levels required for sustenance of glycolysis due to diversion to syringaldehyde detoxification, resulting in inability of C. beijerinckii to transition from acidogenesis to solventogenesis (Zhang et al. 2011). To test this hypothesis, syringaldehyde concentration in the syringaldehyde-supplemented P2 fermentation medium was analyzed. Figure 4 indicates that C. beijerinckii cells grown in syringaldehyde-supplemented P2 medium did not metabolize syringaldehyde but butanol production was negatively affected. Therefore, the failure of C. beijerinckii to transition from acidogenic to solventogenic phase was not as a result of depletion of cofactors pool due to syringaldehyde detoxification.Fig. 4

View Article: PubMed Central

ABSTRACT

While lignocellulosic biomass excels as a cheap, renewable resource for biofuel production, it does present some challenges such as generation of microbial inhibitory compounds. The mode of selective inhibition of acetone–butanol–ethanol (ABE) production (as opposed to cell growth) by syringaldehyde on Clostridium beijerinckii NCIMB 8052 was examined. C. beijerinckii 8052 grown in syringaldehyde-supplemented P2 medium had a comparable growth rate (μ = 0.34) at acidogenic growth phase to that of C. beijerinckii 8052 grown in control P2 medium (μ = 0.30). The addition of syringaldehyde into P2 medium inhibited solvent production by C. beijerinckii 8052 and increased butyric and acetic acid accumulation in the fermentation broth. Analysis of coenzyme A transferase (CoAT) using cell-free extracts of C. beijerinckii 8052 showed decreased expression and activity in the presence of syringaldehyde. These results indicate that C. beijerinckii 8052 CoAT is negatively affected by syringaldehyde and thus, hampers the ability of the microorganism to metabolize butyric and acetic acid for ABE production as evidenced by the accumulation of butyric and acetic acid in the fermentation broth.

No MeSH data available.