Team:Tokyo Tech/Iron-oxidizing bacteria

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Contents

Iron-oxidizing bacteria

Role in the story

Why do we need to use Iron-oxidizing bacteria for terraforming of Mars? Heterotrophic bacteria cannot live in native Martian environment because there are no organic matters on Mars, however autotrophic bacteria can live without organic matters. Iron-oxidizing bacteria is autotrophic bacteria. Iron-oxidizing bacteria gets energy by oxidizing Fe(Ⅱ). To grow on Mars, iron-oxidizing bacteria require only energy injection of us because of composition of the Martian surface, crust and atmosphere. (リンク) We propose culturing iron-oxidizing bacteria on Mars and producing organic matters. Accumulation of organic matters provides habitable environment for heterotrophic bacteria (for instance, E.coli).

About iron-oxidizing bacteria

Iron-oxidizing bacterium is a kind of autotrophic bacteria. Iron-oxidizing bacteria reduce NAD+ to NADH by transfer of hydride. In laboratory, iron-oxidizing bacteria are cultured in 9K medium (リンク) which contains Fe(Ⅱ) and no organic matters.

Experimental result

We cultured Acidithiobacillus ferrooxidans (iron-oxidizing bacteria). The medium for A.ferrooxidans was blue before cultivation owing to Fe(Ⅱ). The presence of A.ferrooxidans changed the medium into brown one after culturing for two days. This change was observed owing to the production of Fe(OH)3. We confirmed the growth by using microscope of 200 magnifications.

Protocols

Preparation of 9K medium (for Acidithiobacillus ferrooxidans)

  • Prepare following A&B solution.
Solution A
Solution B
  • Sterilize A solution by autoclaving.
  • Sterilize B solution by using filter.
  • Mix solution A and B before use.
  • A solution can be stored for 2 weeks.

Culturing method

Culture in 9K medium at 30℃ with vigorous shaking. Use the microscope when confirm the growth.