[O-08] Poster presentations by senior high school students

[O08-P69] Optimization of Methane Fermentation with Saponin and Future of Biogas Power Generation.

*Rindai Kawanishi¹, *Ryousuke Tsukuda¹, Kazumi Igawa¹ (1.Zushi Kaisei Senior High School in Kanagawa)

Keywords:Environment

Recently, the introduction of methane fermentation biogas power generation by governments, local authorities, NPOs, and businesses has been progressing. As of the end of March 2022, 228 facilities have been introduced in Japan, with an annual power generation capacity of 81,586 kilowatts. Biogas power generation is one of the resource recovery technologies that utilizes organic matter such as kitchen waste, paper waste, and livestock manure, which generates methane gas when decomposed by microorganisms in anaerobic conditions, as fuel for power generation. There are three main advantages to promoting the introduction of biogas power generation by various organizations. First, biogas power generation can utilize kitchen waste and paper waste, which are currently disposed of as garbage, as resources. By reducing the amount of waste, it is possible to reduce the emission of carbon dioxide, a major cause of global warming. In addition, in areas where power generation facilities are introduced, locally discarded kitchen waste and livestock manure can support the region's power supply as resources and can also be used as fertilizer for achieving a resource-circulating community. Furthermore, since the available volume of livestock manure is unlikely to fluctuate, compared to other renewable energies that are easily influenced by weather and geographical conditions, biogas power generation can supply electricity stably, which is another advantage. However, despite these various benefits, there are also disadvantages that hinder the introduction of biogas power generation. One such disadvantage is the significant cost involved in the installation of facilities and the management and sorting of kitchen waste and livestock manure. To enhance the cost-effectiveness, which is currently a major obstacle, and to promote the introduction, it is necessary to improve the efficiency of methane production used for power generation. Therefore, we began research on the use of saponin, commonly known as a microbial activator, to activate methane production and contribute to the promotion of biogas power generation. Saponin is a bitter component found in the roots, leaves, and stems of leguminous plants, and when dissolved in water and mixed well, it can produce soap-like foam, so it is called "natural surfactant." In addition, since saponin is expected to have antioxidant effects, improve immunity, prevent obesity, improve blood flow, and enhance liver function,its effects on health and diet have been attracting attention recently. Foods known to contain a particularly high amount of saponin include soy products and burdock skin. We decided to conduct experiments to extract saponin from burdock skin, which contains a high amount of saponin, and add it to the methane fermentation process to investigate how much methane fermentation is accelerated. In the experiments, a carbon dioxide concentration meter is used. Glucose is added to mud containing microorganisms involved in methane fermentation and fermented for a certain period, and then the generated carbon dioxide is measured. Since the gas that can be measured is only carbon dioxide, the experiment needs to be divided into three parts: The first experiment measures the amount of carbon dioxide generated as a by-product during methane fermentation, the second experiment indirectly examines the amount of methane generated by burning the generated gas and using the amount of carbon dioxide generated at that time to calculate the amount of methane, and the third experiment is to examine the effect of saponin by shortening the fermentation period compared to the first and second experiments and burning the gas generated in the same way as in the second experiment. Based on these experiments, we decided to conduct research on the promoted efficiency of methane fermentation by saponin and the possibility of biogas power generation.