Fabrication of designable bio-based adsorbents for precious metals

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21853
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 64:Environmental conservation measure and related fields
• Research Institution: Hokkaido University
• Principal Investigator: Nakashima Kazunori 北海道大学, 工学研究院, 准教授 (50540358)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 金属結合ペプチド / 都市鉱山 / ファージディスプレイ法 / バイオベースマテリアル

Outline of Final Research Achievements

We have developed novel metal adsorbents composed of bio-based materials, cellulose and proteins. Many kinds of metal-binding proteins and peptides are reported in nature or by directed molecular evolution methods. However, proteins and peptide are usually dissolved in water and cannot be used for metal ion recovery from aqueous solution. Therefore, we tried to immobilize metal-binding proteins/peptides on water-insoluble cellulose via carbohydrate binding module (CBM), which is known to bind to cellulose. We constructed fusion proteins composed of metal-binding proteins/peptides and CBM, where a metal-binding part of the fusion proteins is variable or modifiable depending on target metal ions including Au and Pd. The fusion proteins were strongly adsorbed on cellulose and could be used for precious metal ion recover from aqueous solution. Adsorbed metal ions can be desorbed from cellulose by using stripping agents, and continuous metal recovery system using column was also developed.

Free Research Field

資源環境工学

Academic Significance and Societal Importance of the Research Achievements

有価金属の回収や有害重金属の除去などに用いられる金属イオン吸着剤は，通常合成ポリマー（樹脂）を支持体として作製されているが，将来的な低炭素社会の構築およびSDGs達成のためには，石油化学品に置き換わる新たな材料・技術の開発が必要である。本研究で開発した貴金属回収剤はタンパク質と天然高分子のみからなり，さらにターゲット金属に応じて配位子を変えることができるグリーンかつ機能的な新たな概念の金属吸着材料である。この技術は，有価金属の回収のみならず，重金属汚染水の浄化，食品・医療分野での有害金属の除去など，資源・環境・食品・バイオメディカルなど様々な分野へ応用できる基盤技術になると期待される。