TITLE:
Improvement of Renewable Bioenergy Production in Microbial Fuel Cells with Saponin Supplementation
AUTHORS:
Skylar Choi, Yongjin Park, Immanuel H. Anaborne, Jin Sik Song, Ji Woo Han, So Hyun Jeon, Jaewoo Kim, James Kim, Jinkwon Lee, Paul S. Chung
KEYWORDS:
Microbial Fuel Cells, Saponin, Bioenergy
JOURNAL NAME:
Journal of Sustainable Bioenergy Systems,
Vol.11 No.2,
June
18,
2021
ABSTRACT: Microbial fuel cell (MFC) is
one of renewable biofuel production technology that directly converts biomass
to electricity. Cellulosic biomass is particularly attractive renewable
resources for its low cost and abundance and neutral carbon balance. However,
methanogenesis remains as a major factor limiting MFC performance. The current
study reports that saponin addition at 0.05% w/v dose to anolyte in MFCs
inhibited methanogenesis and improves power generation and cellulose
fermentation. Mediator-less two chamber H-type MFCs were prepared using rumen fluid as anode inocula at 20% v/v of
anolyte to convert finely ground pine tree (Avicel) at 2%, w/v to electricity.
Saponin was added to the anode of MFC at 0.005% or 0.05% v/v dosage for
treatment. MFC power and current across an external resistor were
measured daily for 10d. On d10, collected gases from anode compartment were
measured for total gas volume and analyzed for gas composition on gas
chromatography. Supplementation of saponin to MFC at 0.005% did not have any
effects on electricity generation or biogas production and composition. Saponin
at 0.05% dose reduced 10% of methane production and increased 40% of CO2 production and 6.4% of total gas production for 10d MFC operation. Voltage
across resistor prior to treatment addition (d0) was 164.75 ± 9.07 mV. In
control group, voltage across resistor did not change (P = 0.9153) with time
course and mean was 167.8 ± 8.20 mV ranged from 157 to 174.5 mV during 10d
operation. In 0.05% Saponin group, voltage across resistor increased (P 0.0001) after d2 and mean was
187.3 ± 4.30 mV ranged between 161.5 and 204.0 mV and the 10d mean of voltage
across resistor in 0.05% Saponin was greater (P 0.0001) than in control group. 0.05% Saponin also had
greater voltage across resistor at d5 (P = 0.0030) and d6 (P = 0.0246) than
control. End point potential increased (P 0.0001) in 0.05% Saponin after d2. 0.05% Saponin had
greater (P 0.0001) in 0.05% Saponin. Power density increased (P
0.0001) after d2 in 0.05% Saponin. 0.05% Saponin MFCs had greater (P 0.0001) overall mean of 10d
operation. The current study provides strong background for potential use of
saponin and saponin containing natural resources for methanogenesis inhibitor
and cellulolysis enhancer in MFC and also cellulolysis reactors.