Article presentation on Carbon dioxide valorization

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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

2. OUTLINE
INTRODUCTION
OBJECTIVE
MATERIALS AND METHODS
RESULTS AND DISCUSSION
CONCLUSIONS
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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