Microbial community dynamics in mesophilic and thermophilic batch reactors under methanogenic, phenyl acid-forming conditions.

Autor: Prem EM; 1Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria., Stres B; 2Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.; 3Institute of Sanitary Engineering, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova 2, 1000 Ljubljana, Slovenia.; 4Department of Automation, Biocybernetics and Robotics, Jozef Štefan Institute, Jamova 39, 1000 Ljubljana, Slovenia., Illmer P; 1Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria., Wagner AO; 1Department of Microbiology, Universität Innsbruck, Technikerstraße 25d, 6020 Innsbruck, Austria.
Jazyk: angličtina
Zdroj: Biotechnology for biofuels [Biotechnol Biofuels] 2020 May 06; Vol. 13, pp. 81. Date of Electronic Publication: 2020 May 06 (Print Publication: 2020).
DOI: 10.1186/s13068-020-01721-z
Abstrakt: Background: Proteinaceous wastes exhibit high theoretical methane yields and their residues are considered valuable fertilisers. The routine anaerobic degradation of proteins often raises problems like high aromatic compound concentrations caused by the entry of aromatic amino acids into the system. A profound investigation of the consequences of aromatic compound exposure on various microorganisms, which cascade-like and interdependently degrade complex molecules to biogas, is still pending.
Results: In mesophilic samples, methane was predominantly produced via acetoclastic methanogenesis. The highest positive correlation was observed between phenylacetate (PAA) and Psychrobacter spp. and between phenylpropionate (PPA) and Haloimpatiens spp. Moreover, Syntrophus spp. negatively correlated with PAA (Spearman's rank correlations coefficient (rs) = - 0.46, p  < 0.05) and PPA concentrations (rs = - 0.44, p  < 0.05) and was also associated with anaerobic benzene ring cleavage. In thermophilic samples, acetate was predominantly oxidised by Tepidanaerobacter spp. or Syntrophaceticus spp. in syntrophic association with a hydrogenotrophic methanogen. The genera Sedimentibacter and Syntrophaceticus correlated positively with both PAA and PPA concentrations. Moreover, Sedimentibacter spp., Tepidanaerobacter spp., Acetomicrobium spp., and Sporanaerobacter spp. were significant LEfSe (linear discriminant analysis effect size) biomarkers for high meso- as well as thermophilic phenyl acid concentrations. Direct negative effects of phenyl acids on methanogenic properties could not be proven.
Conclusions: Anaerobic phenyl acid formation is not restricted to specific microbial taxa, but rather done by various meso- and thermophilic bacteria. The cleavage of the highly inert benzene ring is possible in methanogenic batch reactors-at least in mesophilic fermentation processes. The results indicated that phenyl acids rather affect microorganisms engaged in preceding degradation steps than the ones involved in methanogenesis.
Competing Interests: Competing interestsThe authors declare that they have no competing interests.
(© The Author(s) 2020.)
Databáze: MEDLINE
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