Cargando…

Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria

Carbon monoxide (CO)-metabolizing Clostridium spp. were enriched from the biomass of a butanol-producing reactor. After six successive biomass transfers, ethanol production reached as much as 11.8 g/L with minor accumulation of acetic acid, under intermittent gas feeding conditions and over a wide p...

Descripción completa

Detalles Bibliográficos
Autores principales: He, Yaxue, Lens, Piet N. L., Veiga, María C., Kennes, Christian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8585497/
https://www.ncbi.nlm.nih.gov/pubmed/34777310
http://dx.doi.org/10.3389/fmicb.2021.754713
_version_ 1784597704052047872
author He, Yaxue
Lens, Piet N. L.
Veiga, María C.
Kennes, Christian
author_facet He, Yaxue
Lens, Piet N. L.
Veiga, María C.
Kennes, Christian
author_sort He, Yaxue
collection PubMed
description Carbon monoxide (CO)-metabolizing Clostridium spp. were enriched from the biomass of a butanol-producing reactor. After six successive biomass transfers, ethanol production reached as much as 11.8 g/L with minor accumulation of acetic acid, under intermittent gas feeding conditions and over a wide pH range of 6.45–4.95. The molar ratio of ethanol to acetic acid exceeded 1.7 after the lag phase of 11 days and reached its highest value of 8.6 during the fermentation process after 25 days. Although butanol production was not significantly enhanced in the enrichment, the biomass was able to convert exogenous butyric acid (3.2 g/L) into butanol with nearly 100% conversion efficiency using CO as reducing power. This suggested that inhibition of butanol production from CO was caused by the lack of natural butyric acid production, expectedly induced by unsuitable pH values due to initial acidification resulting from the acetic acid production. The enriched Clostridium population also converted glucose to formic, acetic, propionic, and butyric acids in batch tests with daily pH adjustment to pH 6.0. The Clostridium genus was enriched with its relative abundance significantly increasing from 7% in the inoculum to 94% after five successive enrichment steps. Unidentified Clostridium species showed a very high relative abundance, reaching 73% of the Clostridium genus in the enriched sludge (6th transfer).
format Online
Article
Text
id pubmed-8585497
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-85854972021-11-12 Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria He, Yaxue Lens, Piet N. L. Veiga, María C. Kennes, Christian Front Microbiol Microbiology Carbon monoxide (CO)-metabolizing Clostridium spp. were enriched from the biomass of a butanol-producing reactor. After six successive biomass transfers, ethanol production reached as much as 11.8 g/L with minor accumulation of acetic acid, under intermittent gas feeding conditions and over a wide pH range of 6.45–4.95. The molar ratio of ethanol to acetic acid exceeded 1.7 after the lag phase of 11 days and reached its highest value of 8.6 during the fermentation process after 25 days. Although butanol production was not significantly enhanced in the enrichment, the biomass was able to convert exogenous butyric acid (3.2 g/L) into butanol with nearly 100% conversion efficiency using CO as reducing power. This suggested that inhibition of butanol production from CO was caused by the lack of natural butyric acid production, expectedly induced by unsuitable pH values due to initial acidification resulting from the acetic acid production. The enriched Clostridium population also converted glucose to formic, acetic, propionic, and butyric acids in batch tests with daily pH adjustment to pH 6.0. The Clostridium genus was enriched with its relative abundance significantly increasing from 7% in the inoculum to 94% after five successive enrichment steps. Unidentified Clostridium species showed a very high relative abundance, reaching 73% of the Clostridium genus in the enriched sludge (6th transfer). Frontiers Media S.A. 2021-10-28 /pmc/articles/PMC8585497/ /pubmed/34777310 http://dx.doi.org/10.3389/fmicb.2021.754713 Text en Copyright © 2021 He, Lens, Veiga and Kennes. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
He, Yaxue
Lens, Piet N. L.
Veiga, María C.
Kennes, Christian
Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria
title Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria
title_full Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria
title_fullStr Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria
title_full_unstemmed Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria
title_short Enhanced Ethanol Production From Carbon Monoxide by Enriched Clostridium Bacteria
title_sort enhanced ethanol production from carbon monoxide by enriched clostridium bacteria
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8585497/
https://www.ncbi.nlm.nih.gov/pubmed/34777310
http://dx.doi.org/10.3389/fmicb.2021.754713
work_keys_str_mv AT heyaxue enhancedethanolproductionfromcarbonmonoxidebyenrichedclostridiumbacteria
AT lenspietnl enhancedethanolproductionfromcarbonmonoxidebyenrichedclostridiumbacteria
AT veigamariac enhancedethanolproductionfromcarbonmonoxidebyenrichedclostridiumbacteria
AT kenneschristian enhancedethanolproductionfromcarbonmonoxidebyenrichedclostridiumbacteria