1. Parameters of biogas production:
the microbial connection
Gert J.H.Hofstede, Expertise Centre ALIFE, Institute for Life Sciences and Technology,
HanzeUniversity of Applied Sciences, Groningen, the Netherlands
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2. Parameters of biogas production:
the microbial connection
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3. Parameters of biogas production: the microbial connection
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Dr. Ir. Jan Peter Nap
(lector)
Dr. Folkert Faber
(senior lecturer)
Brian Wouterse
(trainee)

4. Parameters of biogas production:
the microbial connection
In the Netherlands:
 About ~180 biogas installations.
 In these installations manure and residual
materials are (co-)digested.
 0,5 billion (=109) m3 biogas is produced
 Green electricity can be generated.
Current situation:
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5. Parameters of biogas production:
the microbial connection
Current situation:
 Relatively limited knowledge on the complex
community of microorganisms
 The economy of biogas plants does not allow
failure (cleaning and restarting)
 Fairly conservative enterprise
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6. Parameters of biogas production:
the microbial connection
Why this research ?
 The use of defined digestate of microorganisms
targeted towards the feedstock might speed up
biogas production.
 Opening the microbial black box is supposed to
increase biogas yield and the overall process
efficiency.
 The overall objective of this research is to describe
the microbial community that participates in the AD
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7. Parameters of biogas production:
the microbial connection
 Have different biomasses distinct biomethane
potentials?
 Are different methanogenic communities,
responsible for biogas production?
 Is the methanogenic community influenced by
different environments and different process
parameters?
Research question
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8. Parameters of biogas production: the microbial connection
Experimental tools
 Automatic Methane Potential Test System
(AMPTSII)  batch
 2 Labscale bioreactor (10 l, Infors) 
continuous
 Molecular techniques (qPCR )
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9. Parameters of biogas production: the
microbial connection
AMPTSII, bioprocescontrol
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10. Parameters of biogas production: the microbial connection
AMPTSII-experiments:
 Reproducibility
 3 different digestates
 2 types of biomass
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11. Parameters of biogas production: the microbial connection
 General setup: 15 bottles, 1 type of biomass
(maize), 1 type of digestate (Proces B.V) ,
30 days
 Digestate to biomass ratio of 1:1 (based on
% Organic Dry Matter [ODM]) was used.
General set up of
AMPTSII assays
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Conclusion
 The AMPTSII yields reproducible
results, both in terms of total gas
volume and in terms of methane
production
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13. Parameters of biogas production: the microbial connection
Conclusion:
 No significant difference between
total biogas productions from
maize by different types of digestates
( Donderen, Lutjegast en Tolbert).
 (ANOVA, one-tail, p=0.05).
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14. Parameters of biogas production: the microbial connection
Future-plans:
 In future experiments, we will look the
biogas flow-rate with for example
‘biomass adapted digestates’  the
digestate (Proces B.V) was not
adapted to maize.
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15. Parameters of biogas production: the microbial connection
Future-plans:
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Biogasplants (F1 and F2)
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17. Parameters of biogas production: the microbial connection
The overall objective of this research is to
determine the relative changes in microbial
community that participates in the anaerobic
digestion on a Labscale Infors bioreactor
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18. Parameters of biogas production: the
microbial connection
Methanogens, the biological generators of methane
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19. Parameters of biogas production: the microbial connection
FastRNA® SPIN KIT for SOIL
Total DNA and RNA isolation
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20. Parameters of biogas production: the microbial connection
Primer combinations used in this study
for monitoring the population
dynamics of methanogens in biogas
plants
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21. Parameters of biogas production: the microbial connection
 This study revealed the limitation of the qPCR
due to the primers.  in silico by the RDP-site
 Experimental circumstances probably
influence the ‘reference’ Archaea population
Conclusion/discussion
 Commonly used primers in literature should
be reconsidered in the light of expanding data
in RDP
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22. Parameters of biogas production: the microbial connection
 Since available primers may not be applicable
to all samples,there is a requirement to design
more primers to ensure adequate coverage
and amplification of methanogens.
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Conclusion/discussion

23. Parameters of biogas production: the microbial connection
 Therefore, we also look to at another
approach: mRNA of (key-) enzymes that play a
role in the methanogenesis :
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 Together with Marina Gil Lopez from the
Universitat de Barcelona we did the first
experiments on RNA

24. Parameters of biogas production: the microbial connection
 Identification of Enzymes Involved in synthesis
of biogas
 The challenge is to find (key-)enzymes that
can be linked to (specific methanogenic)
micro-organisms.
 as key enzymes can be linked to micro-
organisms, relative amounts of micro organisms
can be calculated.
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25. Parameters of biogas production: the microbial connection
The future for me? I will end up with a
bucket full of digestate (or micro-
organisms) optimized for every biomass.
That is applied science in my opinion
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Questions
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