The effect of storage conditions on microbial community composition and biomethane potential in a biogas starter culture
- 834 Downloads
A new biogas process is initiated by adding a microbial community, typically in the form of a sample collected from a functional biogas plant. This inoculum has considerable impact on the initial performance of a biogas reactor, affecting parameters such as stability, biogas production yields and the overall efficiency of the anaerobic digestion process. In this study, we have analyzed changes in the microbial composition and performance of an inoculum during storage using barcoded pyrosequencing of bacterial and archaeal 16S ribosomal RNA (rRNA) genes, and determination of the biomethane potential, respectively. The inoculum was stored at room temperature, 4 and −20 °C for up to 11 months and cellulose was used as a standard substrate to test the biomethane potential. Storage up to 1 month resulted in similar final methane yields, but the rate of methane production was reduced by storage at −20 °C. Longer storage times resulted in reduced methane yields and slower production kinetics for all storage conditions, with room temperature and frozen samples consistently giving the best and worst performance, respectively. Both storage time and temperature affected the microbial community composition and methanogenic activity. In particular, fluctuations in the relative abundance of Bacteroidetes were observed. Interestingly, a shift from hydrogenotrophic methanogens to methanogens with the capacity to perform acetoclastic methanogensis was observed upon prolonged storage. In conclusion, this study suggests that biogas inocula may be stored up to 1 month with low loss of methanogenic activity, and identifies bacterial and archaeal species that are affected by the storage.
KeywordsInoculum Anaerobic digestion Methane Biogas Bioenergy Microbial community
This work was financially supported by the ENERGIX-program of the Norwegian Research Council, grants 203402 and 228747.
Conflict of interest
The authors declare that they have no conflict of interest
- Ahring BK, Biswas R, Ahamed A, Teller PJ, Uellendahl H (2014) Making lignin accessible for anaerobic digestion by wet-explosion pretreatment. Bioresour TechnolGoogle Scholar
- Angelidaki I, Alves M, Bolzonella D, Borzacconi L, Campos J, Guwy A, Kalyuzhnyi S, Jenicek P, Van Lier J (2009) Defining the biomethane potential (BMP) of solid organic wastes and energy crops: a proposed protocol for batch assaysGoogle Scholar
- Horn SJ (2013) A tetra-transition away from fossil fuels. In: Sygna L, O’Brien K, Wolf J (eds) A changing environment for human security: transformative approaches to research, policy and action. Earthscan, London, p 392Google Scholar
- Meng J, Xu J, Qin D, He Y, Xiao X, Wang F (2013) Genetic and functional properties of uncultivated MCG archaea assessed by metagenome and gene expression analyses. ISME JGoogle Scholar
- Solli L, Håvelsrud OE, Horn SJ, Rike AG (2014) A metagenomic study of the microbial communities in four parallel biogas reactors. Biotechnol Biofuels 7(1)Google Scholar