Biomass is used to refer to any type of biological resource. Today it is drawing keen attention as an eco-friendly renewable energy source. In particular, waste-derived biomass, including scrap wood from forestry and construction, rice straw, rice husk, animal waste, kitchen waste, and sewage sludge, is generated annually in the volume of millions of tons, bearing great potential as a resource.

Biomass usually has been incinerated for heat recovery or simply disposed of without undergoing any treatment. Foreign countries are strengthening efforts to use more biomass energy, while Japanese government agencies are encouraging the development of biomass technology and implementing a wide variety of biomass energy utilization projects under its new-energy initiative. Among the various types of biomasses, wood biomass is highly renewable because in its production, carbon dioxide is immobilized during the process of photosynthesis. Further, being carbon neutral, wood biomass can effectively reduce greenhouse gases, compared with fossil resources (Figure 1).

Biomass can contribute significantly to the construction of a sustainable society if converted into useful materials such as energy and chemical products.

Biomass refers to biological raw materials. It can be converted into a variety of chemical products, including fuels and biodegradable plastic products. Since plant grow by absorbing CO2, effectively becoming usable as a raw material, biomass can be considered a renewable and sustainable energy source.

Figure 2 shows an example of biomass conversion technology. Various products and conversion technologies may be available, depending on the characteristics of the region and the type of biomass material. Among these technologies, Tsukishima Kikai is focusing mainly on power generation by thermal conversion, as well as the manufacture and storage of ethanol and methane gas by bio conversion.

The biomass ethanol technology Tsukishima Kikai introduced from the U.S. in 2001 (Figure 3) is the high efficient ethanol production technology made from wood waste.

The high reliability of this technology was demonstrated in a pilot experiment in the U.S., using bagasse–sugarcane residue (Figure 4). To apply this technology to construction waste materials, we have been conducting pilot tests on new technologies at our Environmental Process Development Center in Ichikawa-city, Chiba Prefecture.

Using old processes, C5 sugar content could not be converted into ethanol. However, with the BMT process, a genetically modified bacterium is used to convert these sugar content into ethanol. Thus it is now possible to produce ethanol from various types of biomass waste highly efficiently.