Stress response to butyric acid and butanol formation in Clostridium beijerinckii at transcriptional level

abstract

English

Clostridium beijerinckii can produce 1-butanol by acetone-butanol-ethanol (ABE) fermentation from various saccharidic substrates. The ABE fermentation consists of acidogenic and solventogenic phase, which are coupled with exponential and mid-exponential/stationary growth phases, respectively. In acidogenic phase, the main product is butyric acid, which is partly re-utilized to butanol during solventogenesis. However, butanol is simultaneously formed directly from saccharide. The main bottleneck, which hinders industrial application of the process, is low achievable final butanol concentration (max. about 20 g/l) caused by butanol toxicity to the producing cells. However, the first stress factor in the ABE fermentation is accumulation of butyric acid in the medium associated with pHdecrease.During the ABE fermentation, samples were taken for transcriptomic profiling and a stress response elicited by butyrate and butanol formation was mapped. The stress response includes changes in fatty acid metabolism, heat shock protein formation, initiation of sporulation and strengthening in formation of efflux proteins. Detailed analysis of a stress response during ABE fermentation is necessary for strain engineering resulting in more tolerant producing strains.

Clostridium beijerinckii; RNA-Seq

PATÁKOVÁ, P.; VASYLKIVSKA, M.; JUREČKOVÁ, K.; MUSILOVÁ, J.; KOLEK, J.; BRANSKÁ, B.; SEDLÁŘ, K.

8. 9. 2019

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