On Earth, a wide variety of organisms, collectively referred to as biomass, exist both on land and in the oceans. In the oceans, biomass accumulation is relatively low due to the short life cycles of marine organisms. In contrast, terrestrial organisms, especially those in forests (which account for over 90% of total biomass), absorb about one-tenth of atmospheric CO2 each year through photosynthesis. Some of this biomass dies, falls to the ground, and decomposes in the soil, releasing CO2 back into the atmosphere. This carbon cycle between the atmosphere and forest ecosystems is essential for tackling energy and environmental challenges.
Solar energy drives photosynthesis, meaning biomass stores solar energy in the form of chemical energy. Each year, the accumulation of biomass is roughly equivalent to four to five times the world’s total primary energy demand. Biomass energy is considered “carbon neutral” because the CO2 released during its use was originally absorbed from the atmosphere, resulting in net-zero CO2 emissions.
Biomass energy currently accounts for around 10% of the world’s primary energy supply, which is a surprisingly large share. However, this is only 1/40 to 1/50 of the estimated global biomass potential. Doubling the use of biomass could cover 20% of the world’s energy needs, but this must be achieved without disrupting the carbon balance. Currently, biomass energy is mostly used as firewood in developing countries. In contrast, developed countries make limited use of biomass, despite the abundance of waste biomass such as paper, construction materials, and food waste, as it is not considered a high-tech energy source.
Biomass conversion technologies are gaining attention given the current situation. Particularly in developed countries, it is important to convert biomass into advanced energy sources, such as liquid fuels for transportation and electricity. However, these technologies are still in the early stages of development. In our lab, we are working on efficient methods to produce energy and chemicals from biomass.
Competition with food demand is one of the major concerns regarding biomass utilization. The production of bioethanol from edible raw materials like corn and sugarcane competes with food supply, potentially driving up the prices of food crops. In contrast, non-edible resources such as trees, branches, and stems make up the majority of biomass on Earth, while edible resources constitute a minor portion. Thus, the efficient use of non-edible biomass is critical. Lignocellulose, found in materials like wood and grasses, is inedible and primarily composed of cellulose, hemicelluloses, and lignin. Over the course of evolution, lignocellulose has developed a robust structure to defend against microbial attacks, which has made it challenging to convert. This resilience makes biomass utilization difficult—a complex challenge between human ingenuity and nature.
The future of biomass lies in the hands of young students, innovative thinkers. Together, we can build a sustainable, biomass-based society to protect our planet.