A new insight into the strategy for methane production affected by conductive carbon cloth in wetland soil: Beneficial to acetoclastic methanogenesis instead of CO2 reduction

Abstract

Conductive materials/minerals can promote direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogens in defined co-culture systems and artificial anaerobic digesters; however, little is known about the stimulation strategy of carbon material on methane production in natural environments. Herein, the effect of carbon cloth, as a representative of conductive carbon materials, on methane production with incubated wetland soil was investigated. Carbon cloth significantly promoted methanogenesis. With the application of electrochemical technology, calculation of the apparent electron transfer rate constant showed that carbon cloth significantly increased electron transfer rate (ETR) compared with the control experiment in presence of cotton cloth, from 0.0017 ± 0.0003 to 0.0056 ± 0.0015 s. Results obtained from both stable carbon isotope measurements and application of specific inhibitor (CHF) for acetoclastic methanogenesis indicated that carbon cloth obviously promoted acetoclastic methanogenesis instead of CO reduction. High-throughput sequencing showed that methane production may stem from the involvement of Methanosarcina for both treatments. Our findings suggested that conductive carbon material can promote acetoclastic methanogenesis instead of CO reduction in a natural environment.

Methane production by acetate dismutation stimulated by Shewanella oneidensis and carbon materials: An alternative to classical CO2 reduction

“…We sampled a soil from the Yellow River Delta [28,29]. Straw was thus used as the carbon source during pre-incubation for enriching methanogenic archaea.…”

“…where ΔG 0 is ΔG at 273.15 K and 101.325 kPa; R, the ideal gas constant, 8.3145 J•mol −1 •K −1 ; T, the absolute thermodynamic temperature, 303.15 K; C CH4 , C CO2 , and C H2 are concentrations of methane, CO 2 , and H 2 , respectively, mol•L −1 . The calculation of ΔG 0 was detailed referring to a previous study [28].…”

İletken Malzemeleri̇n Kati Organi̇k Atiklardan Bi̇yogaz Üreti̇mi̇ne Etki̇si̇

“…Örneğin Li ve ark. [38] yaptıkları bir çalışmada, karbon kaplamanın oksidasyon-redüksiyon reaksiyonlarına etkisini araştırmışlardır. Bu çalışmada karbon kaplama işlemiyle elektron transfer hızının arttığı gözlemlenmiştir.…”

“…İletken malzeme kullanılarak AP ve metan üretim sürecinin geliştirilmesi ile ilgili çalışmalar genellikle sentetik substrat kullanılarak yapılmıştır [38]. Bu malzemelerin gerçek ortamlarda nasıl bir rol alacağı henüz tam olarak anlaşılamamıştır ve gelecekte bu yönde araştırmalar yapılması biyogaz tesislerinin veriminin iyileştirilmesi adına önemli adımlar olacaktır.…”

Enhanced Anaerobic Digestion by Stimulating DIET Reaction

“…Supplementing CM, specifically magnetite, could interestingly mediate the electron transfer among cells through substituting the pilus-associated cytochrome OmcS that are commonly found in G. sulfurreducens [25]. Li et al [26] observed an increase in electron transfer rate from 0.0017 ± 0.0003 to 0.0056 ± 0.0015 s −1 , as a result of carbon cloth supplementation. Additionally, DIET could be stimulated through the establishment of two electrodes inside AD reactor, under slight EV with/without the presence of CM [3,[27][28][29].…”