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Biogas production from lignocellulosic agricultural residues

microbial approaches for enhanced efficiency

Liu, Tong (2019). Biogas production from lignocellulosic agricultural residues. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2019:5
ISBN 978-91-7760-328-3
eISBN 978-91-7760-329-0
[Doctoral thesis]

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Methane, produced through microbial anaerobic digestion of various organic materials, is seen as a promising sustainable bioenergy source with the potential to reduce the current dependence on fossil fuels. Among organic materials, lignocellulosic materials, especially agriculture residues, are highly interesting due to high abundance and potential for methane production. However, low nutrient content and highly recalcitrant structure often limit process efficiency. This thesis presents the results of in-depth studies conducted in order to obtain new information about lignocellulose-degrading bacteria in biogas processes and to identify ways to enable more efficient biogas production.

Different biogas processes were investigated in terms of their overall microbial community (bacteria and archaea) and potential lignocellulose degraders. The results showed that the biogas processes differed with regard to overall microbial community and chemical composition, but also composition of the cellulose-degrading bacterial community. These differences significantly influenced the degradation efficiency of both cellulose and wheat straw in batch digestion systems and also performance during start-up of semi-continuous stirred tank reactor (CSTR) processes. A positive correlation was found between lignocellulose degradation efficiency and relative abundance of Clostridium cellulolyticum. Ammonia level in the inoculum was identified as the most significant factor potentially affecting microbial community structure and methane production from lignocellulosic materials. Microbial and chemical composition of the original inoculum sources also influenced long-term degradation of lignocellulose in CSTR and appeared to influence residual methane potential. Different molecular methods for microbial community analysis were explored, with the aim of building an appropriate pipeline for in-depth studies of lignocellulose degraders in anaerobic reactors.

This thesis provides novel information about the microbial communities involved in degradation of lignocellulosic materials and possible connections to process parameters. This information could potentially enable biogas production to be steered towards a more efficient and controllable process for degradation and biogas production from agriculture residues and plant-based materials.

Authors/Creators:Liu, Tong
Title:Biogas production from lignocellulosic agricultural residues
Subtitle:microbial approaches for enhanced efficiency
Alternative abstract:

Metan, som produceras genom mikrobiell nedbrytning av olika organiska material under anaeroba förhållanden, ses som en lovande hållbar bioenergikälla med potential att minska det nuvarande beroendet av fossila bränslen. I detta sammanhang representerar jordbruksrester, som finns tillgängligt i stor mängd, en stor metanpotential. Tyvärr har denna typ av material ofta ett lågt näringsinnehåll och ett högt innehåll av lignocellulosa, som är svårt att bryta ner och därför begränsar processens effektivitet. Denna avhandling presenterar resultat från studier som genomförts för att ta fram ny information om bakterier som bryter ner lignocellulosa i biogasprocesser. Målet var att identifiera sätt att möjliggöra en effektivare biogasproduktion.

Olika biogasprocesser undersöktes med avseende på sammansättningen av det mikrobiella samhället (bakterier och arkeer) och bakterier med potentiell förmåga att bryta ner lignocellulosa. För den mikrobiella analysen användes olika molekylära metoder. Resultaten visade att de olika biogasprocesserna var olika i avseende både till den kemiska sammansättningen och det mikrobiella samhället, inklusive de cellulosanedbrytande bakterierna. Dessa skillnader påverkade signifikant nedbrytningseffektiviteten av cellulosa och vetehalm i satsvisa metanproduktionsprocesser. Under dessa försök identifierades en negativ korrelation mellan nedbrytningseffektiviteten och halten ammoniak, samt en positiv korrelation med mängden av en specifik cellulosanedbrytande bakterie, Clostridium cellulolyticum. Uppstart av semi-kontinuerligt omrörda biogasreaktorer (CSTR) visade också tydliga skillnader i processprestanda beroende på ympens ammoniakhalt och på sammansättningen av det mikrobiella samhället. En koppling mellan låg nedbrytningseffektivitet och resterande metanpotential identifierades också.

Kunskap som genererats i denna avhandling kan potentiellt möjliggöra styrning mot en mer effektiv och kontrollerbar process för nedbrytning och biogasproduktion från jordbruksrester och växtbaserade material.

Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :8 January 2019
Depositing date:8 January 2019
Number of Pages:71
ILiu, T., Sun, L., Müller, B. and Schnürer, A. (2016). The microbial community structure in industrial biogas plants influences the degradation rate of straw and cellulose in batch tests. Biotechnology for Biofuels 9, 1-20.
IILiu, T., Sun, L., Müller, B. and Schnürer, A. (2017). Importance of inoculum source and initial community structure for biogas production from agricultural substrates. Bioresource Technology 245, 768-777.
IIILiu, T., Sun, L., Nordberg, Å. and Schnürer, A. (2018). Substrate-induced response in biogas process performance and microbial community relates back to inoculum source. Microorganisms 6, 80-99.
IVAhlberg-Eliasson, K., Liu. T., Nadeau, E. and Schnürer, A. (2018). Forage types and origin of manure in codigestion affect methane yield and microbial community structure. Grass and Forage Science 73, 740-757.
Place of Publication:Uppsala
Publisher:Department of Molecular Sciences, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-7760-328-3
ISBN for electronic version:978-91-7760-329-0
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P06 Renewable energy resources
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Biochemistry and Molecular Biology
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Microbiology (Microbiology in the medical area to be 30109)
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 405 Other Agricultural Sciences > Renewable Bioenergy Research
Keywords:anaerobic digestion, lignocellulose, hydrolase families 5 and 48, biomethane potential, continuous stirred-tank reactor, co-digestion, residual methane potential, next-generation amplicon sequencing, terminal restriction fragment length polymorphism (T-RFLP)
Permanent URL:
ID Code:15820
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Molecular Sciences
External funders:China Scholarship Council
Deposited By: Tong Liu
Deposited On:08 Jan 2019 09:24
Metadata Last Modified:09 Sep 2020 14:17

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