CuxS@SRB bionanohybrid for ultrasensitive electrochemical detection of coenzyme F420: a specific biomarker for Methanogenic archaea.

Methanogenic archaea play a vital role in global methane emission as well as corrosion of oil and gas field equipment. A real-time detection of methanogenic archaea is pivotal for predicting methane (CH4) emission and providing an early warning of microbiological corrosion. While traditional detection methods often take extensive processing time and yield inaccurate results, here, we developed a rapid electrochemical bionanohybrid sensor of the specific coenzyme F420 of the methanogenic archea, by in-situ growth of copper sulfide (CuxS) nanoparticles on electroactive sulfate-reducing bacteria (SRB) in incubation culture. A negatively linear relationship between electroreduction current density and F420 concentration over CuxS@SRB bionanohybrid was found in an ultrawide range of 0.01-1000 nM with an ultralow detection limit of 2.8 pM (S/N = 3). The bionanohybrid exhibited strong robustness against interference by pH variations, temperature changes and other chemicals. We explain the excellent electrochemical sensing through a specific chemisorption due to a Lewis acid-base interaction between Cu+ of CuxS and nitrogen centers in coenzyme F420. The nanohybrid sensor enabled direct quantification of M. maripaludis between 100-107 CFU/mL with a detection limit of 1.8 CFU/mL with a 96.65-103.90% recovery in real pond. This study establishes a new paradigm for rapid detection of methanogenic archaea by exploiting electroactive microorganisms which construct high-performance bionanohybrid electrochemical sensor. This approach offers a broad application in methane emission, carbon cycle analysis, and microbial corrosion early warning systems.