Adaptation of a microbial community to demand-oriented biological methanation

Aghtaei, Hoda Khesali; Benndorf, Dirk; Reichl, Udo

doi:10.1186/s13068-022-02207-w

Cited by 12 publications

(15 citation statements)

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“…These factors include the specific type and concentration of the ingredients, temperature, pressure, flow rheology and degradability of the surfactant [ 37 , 38 ]. Consequently, PU-F68, a synthetic polymer renowned for its exceptional foaming properties, was strategically selected to establish a stabilized liquid foam within a continuously operating TR [ 27 ]. The experiment continued by adding the PU-F68 surfactant to the recirculating liquid phase as a bubble stabilizer and transferring the TR reactor to the TFBR [phase (II) Table 1 ].…”

Section: Resultsmentioning

confidence: 99%

“…Although biomass recycling was undertaken under anaerobic conditions to sustain biomass activity, it is acknowledged that this approach may have led to the lysis of certain community members. Existing evidence suggests the advantageous role of biomass lysate recycling in providing essential nutrients during the BM process [ 27 , 35 , 44 ].…”

Section: Resultsmentioning

confidence: 99%

“…The flexibility and stability of the BM process are of paramount importance, considering PtG as an alternative storage technology for surplus renewable electricity [ 27 , 50 ]. In the scheduled 3-week experiment during phase (II), the mesophilic TFBR was subjected to repeated partial H 2 feeding, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…4 a. Previous research has highlighted the advantages of supplying minimal H 2 feeding compared to the nominal value, preventing variations in microbial community structure when resources are limited; therefore, a shorter recovery time is needed [ 27 , 50 ]. A recent microbial study revealed a distinct resource allocation strategy utilized by a methanogenic archaeon under conditions of energy scarcity, diverging fundamentally from the well-studied versatile chemoheterotrophic bacteria like E. coli [ 51 ].…”

Section: Resultsmentioning

confidence: 99%

“…In addition, employing helically shaped tubes and generating secondary radial flow can further enhance mixing intensity [ 24 – 26 ]. The elongated gas travel path facilitates prolonged interactions between syntrophic microorganisms [ 27 ], hydrogenotrophic methanogens and gaseous substrates. Another advantage of TR systems is the absence of back-mixing with the feeding substrates.…”

Section: Introductionmentioning

confidence: 99%

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Improved biological methanation using tubular foam-bed reactor

Khesali Aghtaei,

Heyer,

Reichl

et al. 2024

Biotechnol Biofuels

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Background Power-to-gas is the pivotal link between electricity and gas infrastructure, enabling the broader integration of renewable energy. Yet, enhancements are necessary for its full potential. In the biomethanation process, transferring H2 into the liquid phase is a rate-limiting step. To address this, we developed a novel tubular foam-bed reactor (TFBR) and investigated its performance at laboratory scale. Results A non-ionic polymeric surfactant (Pluronic® F-68) at 1.5% w/v was added to the TFBR’s culture medium to generate a stabilized liquid foam structure. This increased both the gas–liquid surface area and the bubble retention time. Within the tubing, cells predominantly traveled evenly suspended in the liquid phase or were entrapped in the thin liquid film of bubbles flowing inside the tube. Phase (I) of the experiment focused primarily on mesophilic (40 °C) operation of the tubular reactor, followed by phase (II), when Pluronic® F-68 was added. In phase (II), the TFBR exhibited 6.5-fold increase in biomethane production rate (MPR) to 15.1 $$({\text{L}}_{{\text{CH}}_{4}}\text{/}{\text{L}}_{\text{R}}\text{/d)}$$ ( L CH 4 /L R /d) , with a CH4 concentration exceeding 90% (grid quality), suggesting improved H2 transfer. Transitioning to phase (III) with continuous operation at 55 °C, the MPR reached 29.7 $${\text{L}}_{{\text{CH}}_{4}}\text{/}{\text{L}}_{\text{R}}\text{/d}$$ L CH 4 /L R /d while maintaining the grid quality CH4. Despite, reduced gas–liquid solubility and gas–liquid mass transfer at higher temperatures, the twofold increase in MPR compared to phase (II) might be attributed to other factors, i.e., higher metabolic activity of the methanogenic archaea. To assess process robustness for phase (II) conditions, a partial H2 feeding regime (12 h 100% and 12 h 10% of the nominal feeding rate) was implemented. Results demonstrated a resilient MPR of approximately 14.8 $${\text{L}}_{{\text{CH}}_{4}}\text{/}{\text{L}}_{\text{R}}\text{/d}$$ L CH 4 /L R /d even with intermittent, low H2 concentration. Conclusions Overall, the TFBR’s performance plant sets the course for an accelerated introduction of biomethanation technology for the storage of volatile renewable energy. Robust process performance, even under H2 starvation, underscores its reliability. Further steps towards an optimum operation regime and scale-up should be initiated. Additionally, the use of TFBR systems should be considered for biotechnological processes in which gas–liquid mass transfer is a limiting factor for achieving higher reaction rates.

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Section: Resultsmentioning

confidence: 99%