Effect of Plants Morphological Parameters on Plant-Microbial Fuel Cell Efficiency

Abstract

Background. Plant-microbial fuel cell (PMFC) is an innovative biotechnology for the environmentally safe bioelectricity generation. The widespread use of bioelectrical systems (biosystems) is hindered by their insufficient efficiency due to limiting knowings of the relationship between bioelectricity generation and features of their biotechnological components. Objective. Тhe purpose of this study was to analyze the role of the plants morphological parameters and structure features of biomodules on generation of bioelectricity. Methods. Biometric, biogravimetric, voltammetric, and statistical analysis methods were used to assess the relationship between plant`s accumulated mass of leaf and roots, multielectrode design of biosystem and bioelectricity generation. Results. PMFC based on sedge C. hirta with the largest accumulated total dry leaf/stem and root mass and also the rhizome-like and developed fibrous root system were characterized by the highest power output compared to other biosystems. The power density was 970 ± 22 mW m-2 PGA. The parallel stacking of biomodules leads to obtain current output about 108.7 mA. That is why the developed biotechnological systems can be recommended as a foundation for the development of power supply for WiFi microcontrollers that consume 100 mA or for charging batteries. Conclusions. Sedge С. hirta were appeared as the more suitable plants for biological component of biosystem of bioelectricity generation. Power density of С. hirta based PMFC exceeded the one of based on other plants in 9.3–37.9%.The type and level of development of the root system and of the above-ground photosynthetic surface of plant are an important prognostic factors of the PMFC perfomance. A 10-fold increase of the electrode surface of one biomodule results in 3.95 times increase of power density at 200 W. The multielectrodeity biomodule reveals as another lever for increasing the efficiency of biosystems which allows obtaining significantly increase power density and current density in the range of electrical resistance from 50 to 500 W.