Bioaugmentation of biogas production by a hydrogen-producing bacterium

Abstract

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.

Improving Anaerobic Digestion of Sewage Sludge by Hydrogen Addition: Analysis of Microbial Populations and Process Performance

“…Hence, our results allowed us to hypothesise that due to the conditions in the reactors, the pulses of hydrogen chiefly stimulated the enrichment of certain homoacetogenic microbes above the hydrogenotrophic route. Bioaugmentation by H 2 -producing bacteria has been previously studied for improvement of biogas production and promotion of the hydrogenotrophic pathway [33]. Nevertheless, and contrary to promoting the utilisation of hydrogen and its conversion into methane as expected, the H 2 -producing bacteria present in the CR such as Rhodocyclaceae, Syntrophaceae, and Ruminococcaceae decreased in abundance in the HR when hydrogen pulses were added to the reactor.…”

Long-Term Storage and Use of Artificially Immobilized Anaerobic Sludge as a Powerful Biocatalyst for Conversion of Various Wastes Including Those Containing Xenobiotics to Biogas

“…In order to increase the methanogenesis efficiency and the methane content in the produced biogas, researchers often introduce some additional cells into the methane tank besides the anaerobic sludge. These microorganisms usually stimulate the processes at various stages of the cellulose-containing substrates' conversion into methane: hydrolysis of complex substrates [1,2,37], additional formation of hydrogen [38] and methane [39].…”

Bioaugmentation enhances dark fermentative hydrogen production in cultures exposed to short-term temperature fluctuations

“…Data represents mean values and standard deviation from duplicate cultivations. The red rectangles indicate the point at which the bioaugmentation was applied Drapcho 2011; Akinosho et al 2014). Of all the species added to the synthetic culture, only C. thermocellum was not detected in the final synthetic mixed culture used for bioaugmenting.…”