Thermophilic Anaerobic Digestion of Oil-extracted Microalgae N. gaditana for Biogas Production

66 Pages·2012·8.86 MB·English

Master’s dissertation submitted in partial fulfillment of the requirements for the joint degree of

International Master of Science
in Environmental Technology and Engineering

an Erasmus Mundus Master Course
jointly organized by UGent (Belgium), ICTP (Prague) and UNESCO‐IHE (the Netherlands)

Academic year 2013 – 2014

Thermophilic Anaerobic Digestion of
Oil-extracted Microalgae N. gaditana for
Biogas Production

Host University:
Institute of Chemical Technology Prague, Czech Republic

Capson Tojo, Gabriel

Promoter: Prof. Dr. Ir. Jan Bartáček
Co-promoter: Prof. Dr. Ir. David Jeison Nuñez

This thesis was elaborated at University of La Frontera (Temuco, Chile) and defended at
ICTP (Prague, Czech Republic) within the framework of the European Erasmus Mundus
Programme “Erasmus Mundus International Master of Science in Environmental Technology
and Engineering " (Course N° 2011-0172)

© 2014 Temuco, Gabriel Capson Tojo, Ghent University, all rights reserved.
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Master’s dissertation submitted in partial fulfillment of the requirements for the joint degree of

International Master of Science
in Environmental Technology and Engineering

an Erasmus Mundus Master Course
jointly organized by UGent (Belgium), ICTP (Prague) and UNESCO‐IHE (the Netherlands)

Academic year 2013 – 2014

Thermophilic Anaerobic Digestion of Oil-extracted
Microalgae N. gaditana for Biogas Production

Host Universities:
University of La Frontera, Chile
Institute of Chemical Technology Prague, Czech Republic

Capson Tojo, Gabriel

Promoter: Prof. Dr. Ir. Jan Bartáček
Co-promoter: Prof. Dr. Ir. David Jeison Nuñez
Tutor: Ir. Alvaro Torres Aravena

This thesis was elaborated at University of La Frontera (Temuco, Chile) and defended at ICTP
(Prague, Czech Republic) within the framework of the European Erasmus Mundus Programme
“Erasmus Mundus International Master of Science in Environmental Technology and Engineering "
(Course N° 2011-0172)

© 2014 Temuco, Gabriel Capson Tojo, Ghent University, all rights reserved.
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Certification
I hereby declare that this thesis is my own work. Where other sources of information have
been used, they have been acknowledged and referenced in the list of used literature and other
sources.
I have been informed that the rights and obligations implied by Act No. 121/2000 Coll. on
Copyright, Rights Related to Copyright and on the Amendment of Certain Laws (Copyright
Act) apply to my work. In particular, I am aware of the fact that the Institute of Chemical
Technology in Prague has the right to sign a license agreement for the use of this work as
school work under the nº 60 paragraph 1 of the Copyright Act. I have also been informed that
in the case that this work will be used by myself or that a license will be granted for its usage
by another entity, the Institute of Chemical Technology in Prague is entitled to require from
me a reasonable contribution to cover the costs incurred in the creation of the work, according
to the circumstances up to the full amount.
This is an unpublished M.Sc. thesis and is not prepared for further distribution. The author
and the promoter give the permission to use this thesis for consultation and to copy parts of it
for personal use. Every other use is subject to the copyright laws. More specifically, the
source must be extensively specified when using results from this thesis.
I agree to the publication of my work in accordance with Act No. 111/1998 Coll. on
Higher Education and the amendment of related laws (Higher Education Act).

The Promoter(s) The Author
Prof. David Jeison Nuñez Gabriel Capson Tojo

Prof. Jan Bartáček

Thesis online access release
I hereby authorize the IMETE secretariat to make this thesis available on-line on the
IMETE website.

The Author
Gabriel Capson Tojo
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Acknowledgements
First of all, I need to thank my family for their continuous support and their encouragement
throughout all the period that I lived abroad in order to accomplish this project. During my
stay in Temuco, they passed through very tough times and I was not there to support them.
Particularly, I will always be thankful to my mother and my grandmother, the most incredible
and bravest women I have ever met and will ever meet.
I also have to thank all my friends and colleagues in BIOREN for their help and support,
both professionally and personally, during all the period that I lived in Chile. The most
important person to mention here is my mentor and my friend, Mr. Ir. Alvaro Torres Aravena.
Without his patience and guidance this work would have never been possible.
Last but far from least, I wish to express my gratitude to Mr. Prof. Dr. Ir. David Jeison
Nuñez and Mr. Prof. Dr. Ir. Jan Bartáček for their direction of the thesis and for making
possible this unforgettable experience.

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Preface
This document, named “Thermophilic Anaerobic Digestion of Oil-extracted Microalgae N.
gaditana for Biogas Production” is intended to be a summary and an analysis of the
experimental work performed in the Center of waste management and bioenergy – BIOREN
at University of La Frontera (Temuco, Chile). These research activities were carried out under
the direction and guidance of Mr. Ir. Alvaro Torres Aravena, Mr. Prof. Dr. David Jeison
Nuñez and Mr. Prof. Dr. Jan Bartáček, from February to August of 2014.
As a student of the International Master in Environmental Technology and Engineering
(IMETE), coordinated by Ghent University (Belgium), I had the opportunity of carrying out
my M.Sc. Thesis in the aforementioned Chilean university. The Institute of Chemical
Technology Prague (ICTP), where Mr. Prof. Dr. Jan Bartáček works, is one of the three main
members of the IMETE consortia and, due to an agreement between Mr. Prof. Dr. David
Jeison Nuñez and him, I could come to University of La Frontera to finish this M.Sc.,
performing there all the research activities required for my M.Sc. Thesis and thus obtain the
corresponding title.
In the coming pages, a concise and precise report is presented, explaining clearly the issue
addressed, as well as the theoretical knowledge required to understand the work. All the
research methods utilized are clearly described (or cited) in order to be able to repeat the work
and all the obtained results are discussed, summarizing the main conclusions at the end of the
report.
Again, I wish to express my sincere gratitude to my family, colleagues, promoters and
friends, who have laughed, endured, worked, studied, and basically lived with me during the
last two years.

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“Anything else you’re interested in is not going to
happen if you can’t breathe the air and drink the water.
Don’t sit this one out. Do something”

- Carl Sagan -

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List of contents

Abbreviations & symbols 11

Figures & tables 12

Abstract 14

1. Aim of the work 15
2. Introduction 16
2.1. Potential of microalgae for biofuel production 16
2.1.1. Anaerobic digestion of microalgae for biogas production 18
2.1.2. Biodiesel production from microalgae and subsequent biogas production 19
from lipid extracted microalgal biomass
2.2. Keys issues in microalgal anaerobic digestion 20
2.2.1. Degradability of microalgae cell wall and pretreatment methods 20
2.3. Inhibition during anaerobic digestion of lipid extracted microalgae 22
2.3.1. Ammonia toxicity 22
2.3.2. Marine microalgae and salt inhibition 23
2.3.3. Sulfide inhibition 24
2.3.4. Volatile and long-chain fatty acids 24
2.3.5. Residual solvent toxicity 25
2.4. Anaerobic digestion of microalgae under thermophilic conditions 25
2.4.1. Effect of temperature on the hydrolysis 26
2.4.2. Effect of temperature on inhibition processes 27
3. Materials and methods 29
3.1. Inoculum and substrate 29
3.2. Lipid extraction and characterization of microalgal substrate 29
3.3. Mesophilic and thermophilic biomethane potentials 30
3.4. Set-up of anaerobic bioreactors 30
3.5. Measurement of potential inhibitors 32
3.6. Hydrolytic, acidogenic and methanogenic activities 32
3.7. Lipase and protease enzymatic activities 32
3.8. Analysis of the microalgae structural integrity 33
3.9. Analytical methods 33
3.10. Statistical analysis 34
3.11. Experimental summary 35
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4. Results and discussion 36
4.1. Microalgal biomass characterization 36
4.1.1. Lipid extraction and microalgae characterization 36
4.1.2. Structural integrity of microalgal biomass after lipid extraction and 37
influence of the drying temperature
4.2. Biomethane potential tests 39
4.3. Continuous anaerobic bioreactors 42
4.3.1. Reactors operation 42
4.3.2. Potential inhibitors 46
4.3.3. Influence of acclimation of the thermophilic sludge on the BMP 47
4.3.4. Hydrolytic, acidogenic and methanogenic activities 48
4.3.5. Products from enzymatic degradation 49
4.3.6. Qualitative analysis of microalgae degradation during anaerobic 50
digestion
5. Conclusions 52
6. Recommendations for future research 53
7. Bibliography 54
ANNEX I 61
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