Abstract

Medium-chain fatty acids (MCFA) are important biofuel precursors. Carbon monoxide (CO) is a sustainable electron and carbon donor for fatty acid elongation, since it is metabolized to MCFA precursors, it is toxic to most methanogens, and it is a waste product generated in the gasification of waste biomass. The main objective of this work was to determine if the inhibition of methanogenesis through the continuous addition of CO would lead to increased acetate or MCFA production during fermentation of ethanol. The effects of CO partial pressures (PCO; 0.08-0.3atm) on methanogenesis, fatty acids production, and the associated microbial communities were studied in batch cultures fed with CO and ethanol. Methanogenesis was partially inhibited at PCO≥0.11atm. This inhibition led to increased acetate production during the first phase of fermentation (0-19 days). However, a second addition of ethanol (day 19) triggered MCFA production only at PCO≥0.11 atm, which probably occurred through the elongation of acetate with CO-derived ethanol and H2:CO2. Accordingly, during the second phase of fermentation (days 20-36), the distribution of electrons to acetate decreased at higher PCO, while electrons channeled to MCFA increased. Most probably, Acetobacterium, Clostridium, Pleomorphomonas, Oscillospira, and Blautia metabolized CO to H2:CO2, ethanol and/or fatty acids, while Peptostreptococcaceae, Lachnospiraceae, and other Clostridiales utilized these metabolites, along with the provided ethanol, for MCFA production. These results are important for biotechnological systems where fatty acids production are preferred over methanogenesis, such as in chain elongation systems and microbial fuel cells.

Original languageEnglish (US)
JournalBiotechnology and Bioengineering
DOIs
StateAccepted/In press - 2017

Fingerprint

Partial Pressure
Carbon Monoxide
Fatty acids
Carbon monoxide
Partial pressure
Fermentation
Ethanol
Fatty Acids
Acetates
Elongation
Electrons
Acetobacterium
Bioelectric Energy Sources
Methanogens
Waste Products
Microbial fuel cells
Clostridium
Batch Cell Culture Techniques
Biofuels
Poisons

Keywords

  • Acetobacterium
  • CO fermentation
  • CO partial pressure
  • Fatty acid chain elongation
  • Methanogenesis
  • Peptostreptococcaceae

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology

Cite this

@article{5ed42b88b6714baa9a4ff20cb3f4200d,
title = "Impact of carbon monoxide partial pressures on methanogenesis and medium chain fatty acids production during ethanol fermentation",
abstract = "Medium-chain fatty acids (MCFA) are important biofuel precursors. Carbon monoxide (CO) is a sustainable electron and carbon donor for fatty acid elongation, since it is metabolized to MCFA precursors, it is toxic to most methanogens, and it is a waste product generated in the gasification of waste biomass. The main objective of this work was to determine if the inhibition of methanogenesis through the continuous addition of CO would lead to increased acetate or MCFA production during fermentation of ethanol. The effects of CO partial pressures (PCO; 0.08-0.3atm) on methanogenesis, fatty acids production, and the associated microbial communities were studied in batch cultures fed with CO and ethanol. Methanogenesis was partially inhibited at PCO≥0.11atm. This inhibition led to increased acetate production during the first phase of fermentation (0-19 days). However, a second addition of ethanol (day 19) triggered MCFA production only at PCO≥0.11 atm, which probably occurred through the elongation of acetate with CO-derived ethanol and H2:CO2. Accordingly, during the second phase of fermentation (days 20-36), the distribution of electrons to acetate decreased at higher PCO, while electrons channeled to MCFA increased. Most probably, Acetobacterium, Clostridium, Pleomorphomonas, Oscillospira, and Blautia metabolized CO to H2:CO2, ethanol and/or fatty acids, while Peptostreptococcaceae, Lachnospiraceae, and other Clostridiales utilized these metabolites, along with the provided ethanol, for MCFA production. These results are important for biotechnological systems where fatty acids production are preferred over methanogenesis, such as in chain elongation systems and microbial fuel cells.",
keywords = "Acetobacterium, CO fermentation, CO partial pressure, Fatty acid chain elongation, Methanogenesis, Peptostreptococcaceae",
author = "Sofia Esquivel-Elizondo and Joseph Miceli and Cesar Torres and Rosa Krajmalnik-Brown",
year = "2017",
doi = "10.1002/bit.26471",
language = "English (US)",
journal = "Biotechnology and Bioengineering",
issn = "0006-3592",
publisher = "Wiley-VCH Verlag",

}

TY - JOUR

T1 - Impact of carbon monoxide partial pressures on methanogenesis and medium chain fatty acids production during ethanol fermentation

AU - Esquivel-Elizondo, Sofia

AU - Miceli, Joseph

AU - Torres, Cesar

AU - Krajmalnik-Brown, Rosa

PY - 2017

Y1 - 2017

N2 - Medium-chain fatty acids (MCFA) are important biofuel precursors. Carbon monoxide (CO) is a sustainable electron and carbon donor for fatty acid elongation, since it is metabolized to MCFA precursors, it is toxic to most methanogens, and it is a waste product generated in the gasification of waste biomass. The main objective of this work was to determine if the inhibition of methanogenesis through the continuous addition of CO would lead to increased acetate or MCFA production during fermentation of ethanol. The effects of CO partial pressures (PCO; 0.08-0.3atm) on methanogenesis, fatty acids production, and the associated microbial communities were studied in batch cultures fed with CO and ethanol. Methanogenesis was partially inhibited at PCO≥0.11atm. This inhibition led to increased acetate production during the first phase of fermentation (0-19 days). However, a second addition of ethanol (day 19) triggered MCFA production only at PCO≥0.11 atm, which probably occurred through the elongation of acetate with CO-derived ethanol and H2:CO2. Accordingly, during the second phase of fermentation (days 20-36), the distribution of electrons to acetate decreased at higher PCO, while electrons channeled to MCFA increased. Most probably, Acetobacterium, Clostridium, Pleomorphomonas, Oscillospira, and Blautia metabolized CO to H2:CO2, ethanol and/or fatty acids, while Peptostreptococcaceae, Lachnospiraceae, and other Clostridiales utilized these metabolites, along with the provided ethanol, for MCFA production. These results are important for biotechnological systems where fatty acids production are preferred over methanogenesis, such as in chain elongation systems and microbial fuel cells.

AB - Medium-chain fatty acids (MCFA) are important biofuel precursors. Carbon monoxide (CO) is a sustainable electron and carbon donor for fatty acid elongation, since it is metabolized to MCFA precursors, it is toxic to most methanogens, and it is a waste product generated in the gasification of waste biomass. The main objective of this work was to determine if the inhibition of methanogenesis through the continuous addition of CO would lead to increased acetate or MCFA production during fermentation of ethanol. The effects of CO partial pressures (PCO; 0.08-0.3atm) on methanogenesis, fatty acids production, and the associated microbial communities were studied in batch cultures fed with CO and ethanol. Methanogenesis was partially inhibited at PCO≥0.11atm. This inhibition led to increased acetate production during the first phase of fermentation (0-19 days). However, a second addition of ethanol (day 19) triggered MCFA production only at PCO≥0.11 atm, which probably occurred through the elongation of acetate with CO-derived ethanol and H2:CO2. Accordingly, during the second phase of fermentation (days 20-36), the distribution of electrons to acetate decreased at higher PCO, while electrons channeled to MCFA increased. Most probably, Acetobacterium, Clostridium, Pleomorphomonas, Oscillospira, and Blautia metabolized CO to H2:CO2, ethanol and/or fatty acids, while Peptostreptococcaceae, Lachnospiraceae, and other Clostridiales utilized these metabolites, along with the provided ethanol, for MCFA production. These results are important for biotechnological systems where fatty acids production are preferred over methanogenesis, such as in chain elongation systems and microbial fuel cells.

KW - Acetobacterium

KW - CO fermentation

KW - CO partial pressure

KW - Fatty acid chain elongation

KW - Methanogenesis

KW - Peptostreptococcaceae

UR - http://www.scopus.com/inward/record.url?scp=85033237278&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85033237278&partnerID=8YFLogxK

U2 - 10.1002/bit.26471

DO - 10.1002/bit.26471

M3 - Article

C2 - 28987001

AN - SCOPUS:85033237278

JO - Biotechnology and Bioengineering

JF - Biotechnology and Bioengineering

SN - 0006-3592

ER -