Investigating effects of electron donor availability on cathodic microbial community structure and functional dynamics in electromethanogenesis

الموضوعات

علوم تطبيقية وتكنولوجية

الملخص

Microbial electrochemical technologies (MET) exploit the bioelectrocatalytic activity ofmicroorganisms, with a main focus on waste-to-resource recovery.Electromethanogenesis, a type of MET, describes the process of CO2 reductionspecifically to methane, catalyzed by methanogens that utilize the cathode directly asan electron donor or through H2 evolving from the cathode surface. Applications aremainly in the direction of bioelectrochemical power-to-gas, as well as biogas upgradingand carbon capture and utilization. As the cathode and its associated microbialconsortia are key to the process, larger scale applications require improvementsespecially in terms of optimal operational parameters, cathode materials and thedynamics of the effect of electron transfer within the cathodic biofilm. The focus of thisdissertation is to improve the understanding of the dynamics and function of methaneproducingbiofilms grown on cathodes in electromethanogenic reactors in the presenceof two different electron donors: the cathode and the H2 evolving from the cathodesurface. The spatial homogeneity of the microbial communities across the area of thecathode was demonstrated, which is relevant for large scale applications wherereproducibility is required for predictable engineered systems. Metagenomic andmetatranscriptomic methods were applied to elucidate the short-term changes in theactively transcribed methanogenesis and central carbon assimilation pathways inresponse to varying the availability of electrons by changing the set cathode potential ina novel Methanobacterium species enriched from electromethanogenicbiocathodes. Although changes in functional performance were evident with varyingpotential, no significant differential expression was observed and genes from themethanogenesis and carbon assimilation pathways were highly expressed throughout.Indium tin oxide (ITO) as a potentially hydrogen evolution reaction (HER) – inertcathode material was evaluated using the mixotrophic Methanosarcina barkeri in anattempt to develop a simplified material-science driven approach to future electrontransfer studies. It was found to be electrochemically unstable under the testedconditions, losing its conductivity over time. Overall, the findings from these studiesprovide new knowledge on the effects of electron donor availability on the functionalperformance and the biocathode community dynamics. The understandings derivedfrom the study are relevant to methanogenic processes and should aid in system scaleupdesign.

روابط وملفات

التعريف والنوع

رقم الوثيقة

fafd1341-8fb1-4609-bfbd-70b1de13804f

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

رسائل دكتوراة

نوع الملف

pdf image

أسماء الملفات

fafd1341-8fb1-4609-bfbd-70b1de13804f_1.pdf

بيانات النشر

ألقاب المؤلفين

[{"name_ar":" Pascal Saikaly","title_ar":"اشراف","title_en":"Supervision"},{"name_ar":"Alaa I Ragab","title_ar":"اعداد","title_en":"Preparation"}]

اللغة

English

المصدر والدورية

اسم المصدر

Investigating effects of electron donor availability on cathodic microbial community structure and functional dynamics in electromethanogenesis

المحتوى والصفحات

عدد الصفحات

0

كلمات الباحثين

Electromethanogenesis CO2 capture Metatranscriptomics Biocathode Electron donor availability Hydrogenotrophic Methanogenesis

إشراف وإعداد

الإشراف

Pascal Saikaly

الإعداد

Alaa I Ragab

الاقتباسات الببليوغرافية