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Anaerobic digestion at mesophilic and thermophilic temperature

with emphasis on degradation of phenols and structures of microbial communities

Levén, Lotta (2006). Anaerobic digestion at mesophilic and thermophilic temperature. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2006:116
ISBN 91-576-7265-2
[Doctoral thesis]

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During anaerobic digestion of organic wastes, nutrient-rich digestate is produced. This digestate has great potential as a fertiliser on farmland. However, one concern is the content of organic pollutants in the digestate, as these may influence the soil fertility in the long-term perspective. Different organic pollutants have been found in various organic wastes and types of digestate. This thesis describes the effect of temperature on the anaerobic degradation of different organic pollutant i.e. aromatic compounds and on the structure of microbial communities. To isolate the impact of temperature on the degradation, investigations were carried out in two laboratory-scale bioreactors that were stable and equivalent in performance apart from process temperature and hydraulic retention time. These reactors have treated the same type of organic municipal household waste for many years. The aromatic compounds were chosen to represent important anaerobic reaction steps and key intermediates. Several of the selected compounds were efficiently degraded at the mesophilic temperature (37 ºC). In contrast, phenols and phthalic acid were not degraded at the thermophilic temperature (55 ºC). This limited degradation at the higher temperature is contrary to the general degradation rate of organic matter, which increase with elevated temperatures. Chemical analysis of the digestate from the laboratory-scale reactor operating at thermophilic temperature detected a comparably higher content of phenols, verifying the degradation results. The effect of temperature on phenol degradation was further confirmed in a study including several large-scale bioreactors. To investigate the impact of temperature on microbial community structure, phylogenetic analysis was performed with 16S rRNA genes from the archaeal and bacterial communities in the same two laboratory-scale bioreactors as used for the degradation study. This analysis revealed a lower microbial diversity at the higher temperature. This difference in diversity can possibly explain the observed difference in degradation capacity. The microorganisms responsible for the degradation of phenol were studied in enrichment cultures originating from the two laboratory-scale bioreactors. Two different bacteria were suggested to perform the phenol degradation in these cultures, a finding that highlights the influence of temperature on community structure.

Authors/Creators:Levén, Lotta
Title:Anaerobic digestion at mesophilic and thermophilic temperature
Subtitle:with emphasis on degradation of phenols and structures of microbial communities
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2006
Number of Pages:48
ALLI. Levén, L. & Schnürer A. 2005. Effect of temperature on biological degradation of phenols, benzoates and phthalates under methanogenic conditions. International Biodeterioration & Biodegradation 55, 153-160. II. Levén, L., Nyberg, K., Korkea-aho, L. & Schnürer, A. 2006. Phenols in anaerobic digestion processes and inhibition of ammonia oxidising bacteria (AOB) in soil. Science of the Total Environment 364, 229-238. III. Levén, L., Eriksson, A.R.B. & Schnürer, A. Effect of process temperature on bacterial and archaeal communities in two methanogenic bioreactors treating organic household waste. FEMS Microbiology Ecology, Accepted.
Place of Publication:Uppsala
ISBN for printed version:91-576-7265-2
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:organic wastes, aromatic compounds, phenolic compounds, anaerobic treatment, temperature, microorganisms, microbial ecology, molecular cloning, dna
Keywords:anaerobic degradation, aromatic compounds, digestate, microbial community, molecular cloning, phenols, temperature, 16S rDNA
Permanent URL:
ID Code:1288
Department:(NL, NJ) > Dept. of Microbiology (until 161231)
Deposited By: Lotta Levén
Deposited On:19 Dec 2006 00:00
Metadata Last Modified:02 Dec 2014 10:11

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