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Increasing the Conversion Efficiency of Biomass Into n-caproate With Reactor Microbiomes

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Technical Report,15 Sep 2012,14 Sep 2016

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Cornell University Ithaca United States

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We envision producing medium-chain carboxylic acids from organic feed stocks with open cultures of microbial consortia reactor microbiomes via a bioprocess that is called chain elongation. Our vision is based on the carboxylate platform and combines two fermentation steps into one bioprocess 1. producing short-chain carboxylic acids from variable feed stocks 2. chain elongating these acids into hydrophobic, extractable medium-chain carboxylic acids n-caproic acid and n-caprylic acid. We proposed three different objectives1. To understand how hydrogen partial pressures can influence the production efficiencies of n-caproic acid at mesophilic temperatures 2.To investigate whether changes in the hydrogen partial pressures alter the microbiome composition and 3. To ascertain if reactor microbiomes that operate at thermophilic temperatures can produce n-caproic acid at sufficient rates. We found that hydrogen gas did influence the production rates of medium-chain carboxylic acids, and therefore also likely the microbiome analysis still in progress, but that a higher temperature would not be advisable. At a lower temperature of 30 degrees C we found that lactic acid was converted efficientlyt o n-caproic acid in a continuously fed bioreactor that was operated at mildly acid conditions and with product extraction. This is opening the way to chain elongation with lactic acid.

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  • Organic Chemistry

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