Horizon Net Zero Dawn – keynote slides by Ben Abraham
CO2 Valorization Using Bacteria
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INSTITUTE OF HEALTH SCIENCES
FACULTY OF PUBLIC HEALTH
DEPARTMENT OF ENVIRONMENTAL HEALTH
SCIENCES AND TECHNOLOGY
JUNE,2019
Compiled and presented by: BINIAM BELETE
Tittle:CO2 valorization by a new microbiological process
ARTICLE PRESENTATION
Authors: A. Ruiz-Valencia, et al.
Year of publication: March, 2019
Journal name: Catalysis Today
3. Carbon dioxide accounts for more than 75% of GHG
(GIEC,2014)
These emissions, derive mainly from heavy and
energy producing industries
cement plants, Al &steel production sites
coal & oil-fired power plants, as well as transport
(S. Moret,2014)
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INTRODUCTION
4. Possible solution to reduce levels of CO2 in the
atmosphere;
Use of this gas as a raw material at the
industrial level is currently being studied
• Activation of CO2 molecules is very difficult
because dissociation of the C=O bond requires a
large amount of energy (i.e. 795 kJ mol −1).
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Introduction…cont’d
5. • Chemical conversion routes still exhibit low durability
and/or selectivity.
(F.A. Rahman, 2017)
• The biological processes for CO2 activation are
interesting.
low-energy-consuming and reagent use and/or
by-product release that could have a negative
environmental impact is generally limited.
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Introduction…cont’d
6. • Currently, only processes implementing
microorganisms such as microalgae/cyanobacteria
have been developed at the industrial scale.
The main products recovered from
CO2valorization by these processes are lipids
which can be then converted into biodiesel.
(H.M. Woo,2017 and Z. Wang et al.,2018)
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Introduction…cont’d
7. • At the laboratory scale, cyanobacteria have been
genetically modified to produce alcohols directly
from CO2.
(P. Savakis, 2015 and M. Xie et al.,2017)
• Recently, a methylotrophic bacterium, was
reported to have produced formate from CO2 .
(H. Hwang et al.,2015)
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Introduction…cont’d
8. • In this work, an environmental bacterial
consortium rich in methanotrophic
bacteria was shown to catalyze the
reduction of CO2into formate.
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Introduction…cont’d
9. To assess the ability of bacterial
consortium containing methanotrophic
bacteria to reduce CO2
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OBJECTIVE
10. A bacterial consortium containing methanotrophic
bacteria, was grown in a modified NMS medium
enriched with copper & iron.
The bacteria were grown in sealed vials incubated
at 30 °C on a rotary shaker operated at 160 rpm.
Bacteria and culture conditions
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MATERIALS AND METHODS
11. CO2-reduction tests in batch mode
The batch reactors were 60 mL-glass vials sealed
with aluminium caps.
The bacterial suspension was distributed into the
batch reactors, with 6 mL being added per reactor.
To assess the ability of the consortium to reduce
CO2, several experiments were conducted with
different headspace atmospheres
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Materials and methods…cont’d
12. For experiments A, B and C, a large set of vials
was filled with the same bacterial suspension and
incubated at 30 °C under constant rotation (160
rpm).
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Materials and methods…cont’d
13. • Each experiment was conducted in triplicate and
monitored for 20 days.
• CO2-reduction tests carried out to confirm the
origin of the products arising from CO2 reduction
by carbon NMR analyses.
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Materials and methods…cont’d
14. When exposed to a CO2:air (1:1 v/v)mixture,
The consortium was able to produce 280 ± 10 mg/gdry cell
of formate in 15 days.
When exposed to air, which contains a small
fraction of CO2,formate production was lower
than that of experiment A.
The consortium was able to produce 145 ± 15 mg/gdry cell
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RESULTS AND DISCUSSION
15. A control experiment performed solely with air
coupled to NMR analysis suggested that at least
17% of the formate was produced from direct
CO2 reduction.
The formate produced could be used as:
a precursor for methanol production from methane by
methanotrophic bacteria or
it could be acidified to feed Direct Formic Acid Fuel Cells.
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Results and discussion…cont’d
16. These results;
show that formate production is: CO2 and
bacteria dependent
suggest that formate could be formed from CO2
present in the atmosphere.
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Results and discussion…cont’d
17. • A bacterial consortium containing methanotrophs
was able to reduce CO2 into formate
This bioprocess thus constitutes a new promising
way to valorize CO2.
• At this stage, it is assumed that 17% of the total
formate produced resulted from CO2 reduction;
however, this content needs to be precisely quantified.
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CONCLUSIONS
18. THANK YOU!
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The full content of the article can be accessed from:
https://doi.org/10.1016/j.cattod.2019.03.053