Biorefinery with Open Mixed Cultures for Biofuels and Chemicals Production from Organic Waste

Biodegradation of Unpretreated Cellulose

Davide Dionisi, Ifeoluwa Omotola Bolaji

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

This work fits in the general research area of organic waste conversion to chemicals and fuels using anaerobic digestion. In particular this study investigates the ability of undefined mixed microbial cultures to ferment cellulose to ethanol and organic acids without any chemical or physical pretreatment of the feed. The anaerobic conversion of microcrystalline cellulose was investigated in four batch experiments, carried out at 25 °
C without any pretreatment of the cellulose. The mixed culture effectively fermented the substrates, however cellulose
degradation only occurred after the microorganisms had been acclimated to cellulose in continuous runs, while cellulose was not degraded by unacclimated microorganisms. Acetic acid was the main metabolic product while ethanol, butyric acid and propionic acid were also present in low concentrations. Within 100 days from the start of the batch tests, the cellulose removal was in the range 40-50 %. The maximum concentration of acetic acid
observed was 8.8 g/L while the maximum ethanol concentration was 0.6 g/L. The experimental results demonstrates the capability of open mixed microbial culture to ferment cellulose under
mild conditions. Even though the rates observed in this study are still too low for industrial exploitation, they indicate the potential of mixed cultures to biodegrade cellulose even in the absence of any pretreatments. The next step of the study will be aimed at finding the conditions that increase the cellulose biodegradation rate.
Original languageEnglish
Pages (from-to)157-162
Number of pages6
JournalChemical Engineering Transactions
Volume49
DOIs
Publication statusPublished - Apr 2016

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Biofuels
Biodegradation
Cellulose
Ethanol
Acetic Acid
Microorganisms
Butyric Acid
Anaerobic digestion
Organic acids
Propionic acid
Butyric acid
Acetic acid
Substrates

Cite this

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title = "Biorefinery with Open Mixed Cultures for Biofuels and Chemicals Production from Organic Waste: Biodegradation of Unpretreated Cellulose",
abstract = "This work fits in the general research area of organic waste conversion to chemicals and fuels using anaerobic digestion. In particular this study investigates the ability of undefined mixed microbial cultures to ferment cellulose to ethanol and organic acids without any chemical or physical pretreatment of the feed. The anaerobic conversion of microcrystalline cellulose was investigated in four batch experiments, carried out at 25 °C without any pretreatment of the cellulose. The mixed culture effectively fermented the substrates, however cellulosedegradation only occurred after the microorganisms had been acclimated to cellulose in continuous runs, while cellulose was not degraded by unacclimated microorganisms. Acetic acid was the main metabolic product while ethanol, butyric acid and propionic acid were also present in low concentrations. Within 100 days from the start of the batch tests, the cellulose removal was in the range 40-50 {\%}. The maximum concentration of acetic acidobserved was 8.8 g/L while the maximum ethanol concentration was 0.6 g/L. The experimental results demonstrates the capability of open mixed microbial culture to ferment cellulose undermild conditions. Even though the rates observed in this study are still too low for industrial exploitation, they indicate the potential of mixed cultures to biodegrade cellulose even in the absence of any pretreatments. The next step of the study will be aimed at finding the conditions that increase the cellulose biodegradation rate.",
author = "Davide Dionisi and Bolaji, {Ifeoluwa Omotola}",
note = "Acknowledgments The authors wish to acknowledge the skilful assistance of Mrs Liz Hendrie and Ana Let{\'i}cia Firmino in performing the experiments. The authors also wish to acknowledge Mr Andrew Rennie of Gask Biogas Farm, Turriff, Aberdeenshire, UK, for kindly providing the anaerobic digester sludge.",
year = "2016",
month = "4",
doi = "10.3303/CET1649027",
language = "English",
volume = "49",
pages = "157--162",
journal = "Chemical Engineering Transactions",
issn = "2283-9216",
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AU - Dionisi, Davide

AU - Bolaji, Ifeoluwa Omotola

N1 - Acknowledgments The authors wish to acknowledge the skilful assistance of Mrs Liz Hendrie and Ana Letícia Firmino in performing the experiments. The authors also wish to acknowledge Mr Andrew Rennie of Gask Biogas Farm, Turriff, Aberdeenshire, UK, for kindly providing the anaerobic digester sludge.

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N2 - This work fits in the general research area of organic waste conversion to chemicals and fuels using anaerobic digestion. In particular this study investigates the ability of undefined mixed microbial cultures to ferment cellulose to ethanol and organic acids without any chemical or physical pretreatment of the feed. The anaerobic conversion of microcrystalline cellulose was investigated in four batch experiments, carried out at 25 °C without any pretreatment of the cellulose. The mixed culture effectively fermented the substrates, however cellulosedegradation only occurred after the microorganisms had been acclimated to cellulose in continuous runs, while cellulose was not degraded by unacclimated microorganisms. Acetic acid was the main metabolic product while ethanol, butyric acid and propionic acid were also present in low concentrations. Within 100 days from the start of the batch tests, the cellulose removal was in the range 40-50 %. The maximum concentration of acetic acidobserved was 8.8 g/L while the maximum ethanol concentration was 0.6 g/L. The experimental results demonstrates the capability of open mixed microbial culture to ferment cellulose undermild conditions. Even though the rates observed in this study are still too low for industrial exploitation, they indicate the potential of mixed cultures to biodegrade cellulose even in the absence of any pretreatments. The next step of the study will be aimed at finding the conditions that increase the cellulose biodegradation rate.

AB - This work fits in the general research area of organic waste conversion to chemicals and fuels using anaerobic digestion. In particular this study investigates the ability of undefined mixed microbial cultures to ferment cellulose to ethanol and organic acids without any chemical or physical pretreatment of the feed. The anaerobic conversion of microcrystalline cellulose was investigated in four batch experiments, carried out at 25 °C without any pretreatment of the cellulose. The mixed culture effectively fermented the substrates, however cellulosedegradation only occurred after the microorganisms had been acclimated to cellulose in continuous runs, while cellulose was not degraded by unacclimated microorganisms. Acetic acid was the main metabolic product while ethanol, butyric acid and propionic acid were also present in low concentrations. Within 100 days from the start of the batch tests, the cellulose removal was in the range 40-50 %. The maximum concentration of acetic acidobserved was 8.8 g/L while the maximum ethanol concentration was 0.6 g/L. The experimental results demonstrates the capability of open mixed microbial culture to ferment cellulose undermild conditions. Even though the rates observed in this study are still too low for industrial exploitation, they indicate the potential of mixed cultures to biodegrade cellulose even in the absence of any pretreatments. The next step of the study will be aimed at finding the conditions that increase the cellulose biodegradation rate.

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