Impact of Hinoki Cypress Wood on Diversity of Microflora: A Case Study from Owase City Hall

Hinoki cypress (Chamaecyparis obtusa) shows durability against termites and wood decay-causing fungi and is used as a construction material in Japan. However, the effects of the material are still not fully understood. The aim of this study was to evaluate whether Hinoki cypress has antimicrobial effects against airborne microorganisms. We examined the influence of Hinoki cypress on the growth of airborne bacteria and fungi using culture-based methods. The growth of bacterial colonies was observed after day 3 in the control group without Hinoki material. In contrast, the growth of bacterial colonies was observed after day 13 in the experimental group containing Hinoki material. In the experimental group, the number of fungal colonies was smaller than that in the control group, suggesting the antifungal effect of Hinoki cypress to some extent. In addition, we characterized the community structure of airborne bacteria in two rooms with and without cypress wood by the culture-independent method of PCR-denaturing gradient gel electrophoresis. This also suggested differences in the community structure of airborne bacteria depending on the presence or absence of Hinoki cypress wood. These results indicate that Hinoki cypress might be a useful functional material in building environments.