1. Department of Macromolecular Science Graduate School of Science Osaka University 1‐1 Machikaneyama‐cho Toyonaka Osaka 560‐0043 Japan
2. Department of Polymer Chemistry Graduate School of Engineering Kyoto University Katsura Kyoto 615‐8510 Japan
3. Center for Research and Development of Bioresources Organization for Research Promotion Osaka Prefecture University 1‐2, Gakuen‐cho, Naka‐ku Sakai 599‐8570 Japan