Microalgae and cyanobacteria as biological agents of biocathodes in biofuel cells

Abstract

Biofuel cells (BFCs) are an environmental friendly technology that can simultaneously perform wastewater treatment and generate electricity. Peculiarities that hinder the widespread introduction of this technology are the need to use artificial aeration and chemical catalysts, which make the technology expensive and cause secondary pollution. A possible solution to this issue is the use of biocathodes with microalgae and cyanobacteria. Microalgae in the biocathodic chamber produce oxygen as the terminal electron acceptor. Various BFC technologies with algal biocathode (microbial fuel cells, microbial desalination cells, and plant microbial fuel cells) can address a variety of issues such as wastewater treatment, desalination, and CO 2 capture. The main technological parameters that influence the performance of the biocathode are light, pH, and temperature. These technological parameters affect photosynthetic production of oxygen and organic compounds by microalgae or cyanobacteria, and hence affect the efficiency of electricity production, wastewater treatment and production of added-value compounds in microalgae biomass like lutein, violaxanthin, astaxanthin. The ability to remove carbon, nitrogen, and phosphorus compounds; antibiotics; and heavy metals by pure cultures of microalgae and cyanobacteria and by mixed cultures with bacteria in the cathode chamber can be used for wastewater treatment.

Electrical Energy Generation by Microbial Fuel Cells With Microalgae on the Cathode

“…Considering the observed growth of microalgae biomass during cultivation, this biomass holds promise for the production of biodiesel and carotenoids [28]. Additionally, it opens avenues for the production of value-added products such as lutein, violaxanthin, astaxanthin, and canthaxanthin.…”

Biological Seawater Desalination

“…to their toxicity and cost, it is preferable to use air cathodes, but these also have limitations and require expensive catalysts [62,[68][69][70]. Therefore, a more economical and sustainable alternative was sought, such as cathodes built by living organisms capable of producing oxygen through photosynthesis, known as biocathodes [71][72][73][74]. Some of these MDCs with biocathodes have given rise to more complex designs known as photosynthetic microbial desalination cells (PMDCs) [75][76][77][78][79].…”

Conductive Polymers and Their Nanocomposites: Application Features in Biosensors and Biofuel Cells

“…Microbial biocathodes attract the attention of researchers due to their low cost, the ability of the catalyst to self-regenerate, and their sufficient stability. In this case, a wide variety of aerobic and anaerobic bacteria, cyanobacteria, and microalgae are used as biocatalysts for cathodes [ 242 , 243 ]. In addition, microbial metabolism in biocathodes can be used to produce useful products or remove unwanted compounds from the environment [ 244 ].…”