Direct Energy Extraction from Brown Macroalgae-Derived Alginate by Gold Nanoparticles on Functionalized Carbon Nanotubes

Authors

  • Dr. Le Quynh Hoa,

    Corresponding author
    1. JST, CREST, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
    2. Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
    • Le Quynh Hoa, JST, CREST, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

      Eiichi Tamiya, Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

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  • Dr. Hiroyuki Yoshikawa,

    1. JST, CREST, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
    2. Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
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  • Dr. Masato Saito,

    1. Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
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  • Prof. Dr. Mitsuyoshi Ueda,

    1. JST, CREST, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
    2. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)
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  • Prof. Dr. Toshiyuki Shibata,

    1. JST, CREST, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
    2. Laboratory of Quality in Marine Products, Graduate School of Bioresources, Mie University, Kurima Machiya-cho 1577, Tsu, Mie 514-8507 (Japan)
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  • Prof. Dr. Eiichi Tamiya

    Corresponding author
    1. Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
    • Le Quynh Hoa, JST, CREST, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

      Eiichi Tamiya, Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

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Abstract

The front cover artwork for Issue 01/2014 is provided by the research group of Nano-Bioengineering at the Department of Applied Physics, Osaka University (Japan). The image illustrates the concept of using gold nanoparticle-decorated carbon nanotubes to directly electrochemically oxidize brown macroalgae derived-alginate into valuable chemicals and simultaneously extract bioenergy. Read the full text of the article on page 135.

What prompted you to investigate this topic/problem?

12345Currently, lignocellulosic biomass such as corn and sugarcane are being exploited as renewable energy and chemical resources. The “food-versus-fuel” paradox has, however, sparked significant controversy over their future availability and applicability. Therefore, we have targeted inedible brown macroalgae since they require no fresh water, fertilizer, or arable land and do not interfere with the human food chain. To realize the establishment of brown macroalgae in biorefineries, we work in a research team of the CREST project with other groups who are in search of an appropriate microbial platform that can convert the algae’s sugars to ethanol. Among those sugars, alginate, which accounts for about a third of them, remains a formidable challenge despite the huge investments into genetic engineering processes. To solve this obstacle, we sought to extract energy and valuable chemicals from macroalgae through a fuel cell system that exploits the direct electrochemical oxidation of alginate by gold nanoparticle-decorated functionalized carbon nanotubes, without any external input of energy.

Scheme 1.

Dr. Le Quynh Hoa

Scheme 2.

Dr. Hiroyuki Yoshikawa

Scheme 3.

Dr. Masato Saito

Scheme 4.

Prof. Eiichi Tamiya

Scheme 5.

Department of Applied Physics Osaka University 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan) E-mail: hoa@ap.eng.osaka-u.ac.jp Homepage: http://dolphin.ap.eng.osaka-u.ac.jp/nanobio/

What future opportunities do you see?

Obviously, there is no perfect solution to the search for renewable energy and chemical resources. Although macroalgae have, in principle, huge potential to become the next biofuel, their future is not yet realized as its primary sugar, alginate, is not easily fermented. In addition to traditional genetic engineering approaches, our direct oxidation approach based on designed catalytic systems has provided strong evidence to the capability of macroalgae as cost-effective and renewable sources of biomass. We hope that our preliminary result will attract more catalysis scientists to explore this field as extensively as that of lignocellulosic biomass. Further research could be devoted to the development of inexpensive catalysts by using abundant transition metals.

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Acknowledgements

This work is financially supported by JST, CREST. We are grateful to our colleagues at Osaka University and to our collaborators for stimulating and insightful discussions.

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