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Bioaugmentation of biogas production by a hydrogen-producing bacterium

Ács, Norbert, Bagi, Zoltán, Rákhely, Gábor, Minárovics, János, Nagy, Katalin, Kovács, Kornél L.
Bioresource technology 2015 v.186 pp. 286-293
Enterobacter cloacae, anaerobic digesters, bacteria, bacterial communities, bioaugmentation, biogas, hydrogen, quantitative polymerase chain reaction, restriction fragment length polymorphism
The rate-limiting nature of the hydrogen concentration prevailing in the anaerobic digester has been recognized, but the associated alterations in the microbial community are unknown. In response to the addition of Enterobacter cloacae cells in laboratory anaerobic digesters, the level of biogas production was augmented. Terminal restriction fragment length polymorphism (T-RFLP) and real-time polymerase chain reaction (Real-Time PCR) were used to study the survival of mesophilic hydrogen-producing bacteria and the effects of their presence on the composition of the other members of the bacterial community. E. cloacae proved to maintain a stable cell number and to influence the microbial composition of the system. Bioaugmentation by a single strain added to the natural biogas-producing microbial community was demonstrated. The community underwent pronounced changes as a result of the relatively slight initial shift in the microbiological system, responding sensitively to the alterations in local hydrogen concentration.