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Forage types and origin of manure in codigestion affect methane yield and microbial community structure
Author(s) -
AhlbergEliasson K.,
Liu T.,
Nadeau E.,
Schnürer A.
Publication year - 2018
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/gfs.12358
Subject(s) - biogas , manure , anaerobic digestion , agronomy , cow dung , bioenergy , food waste , environmental science , firmicutes , forage , biofuel , microbial population biology , chicken manure , methane , pulp and paper industry , food science , biology , microbiology and biotechnology , fertilizer , bacteria , ecology , genetics , 16s ribosomal rna , engineering
In farm‐scale biogas systems, different kinds of manure are the most important substrate for anaerobic digestion, but result in low biogas yields. Biogas production can be increased by complementing the manure with forage crops, in codigestion. The aim of this study was to evaluate grass‐clover ( GCS ) and whole‐crop barley silages ( WCB ) in codigestion with manure from organic and conventional dairy production systems on biogas production, microbial community, degree of degradation and gas quality at different organic loading rates by addition of soya bean meal and wheat grain, which are rich in protein and starch. Four continuous stirred anaerobic laboratory‐scale reactors were used, and the codigestion resulted in additive effects on biogas production, but no synergistic effects. The highest biogas yield was obtained in reactors receiving WCB independently of manure types, for both experiments (7,416 ml/day and 10,978 ml/day respectively). The degradation efficiency, measured as the reduction in volatile solids was, on average, six percentage units higher in the reactors receiving manure from conventional compared with organic dairy cows, probably because of a higher concentration of undigested fibre and proteins in conventional cow manure. Microbiological analysis by illumina sequencing illustrated low impact of both manure types on the reactor community and only small differences between the reactors receiving GCS and WCB . However, addition of soya bean meal and wheat grain changed the community in all reactors. The ratio between Firmicutes and Bacteroidetes was comparably higher in reactors having the highest gas production and methane yield.