Team:Korea U Seoul/Design

Design

Design: Gelectricell

Our EMFC has 3 main systems.

1.Agar degradation

We used 3 enzymes to degrade agar in our device which are, Agarase, NABH (Neoagarobiose hydrolase), and AHGD (anhydrogalactose dehydrogenase).

Agar is first degraded into neoagarobiose by agarase. Neoagarosebiose is then degraded into D-galactose and 3.6-anhydro-L-galactose by NABH. 3.6-anhydro-L-galactose is then oxidized by NAD(P)+ dependent AHGD producing NAD(P)H.

All listed enzymes are displayed on the surface of E.coli BW25113 using E.coli surface display vector pATLIC.

2. Shewanella oneidensis MR-1

Shewanella oneidensis MR-1 is a bacteria that can reduce metal instead of oxygen, thus generating electricity in a battery device.

Shewanella oneidesis MR-1 is used in our device to generate electricity using D-galactose. However, Shewanella oneidensis MR-1 is known to be unable to use galactose as its carbon source. This is where co-cultured E.coli kicks in. E.coli BW25113 is able to utilize galactose to produce formate and acetate which Shewanella oneidensis MR-1 can utilize to generate electricity.

3. Diaphorase

Diaphorase is a type of enzyme that can generate electricity using NAD(P)H as the source of electron. It is expressed in BL21(DE3) with protein expression vector pB3.

References

  1. Yun, Eun Ju, et al. "Production of 3, 6-anhydro-L-galactose from agarose by agarolytic enzymes of Saccharophagus degradans 2-40." Process biochemistry 46.1 (2011): 88-93.
  2. Yun, Eun Ju, et al. "The novel catabolic pathway of 3, 6‐anhydro‐L‐galactose, the main component of red macroalgae, in a marine bacterium." Environmental microbiology 17.5 (2015): 1677-1688.
  3. Ko, Hyeok-Jin, et al. "Functional cell surface display and controlled secretion of diverse agarolytic enzymes by Escherichia coli with a novel ligation-independent cloning vector based on the autotransporter YfaL." Applied and environmental microbiology 78.9 (2012): 3051-3058.
  4. Wang, Victor Bochuan, et al. "Metabolite-enabled mutualistic interaction between Shewanella oneidensis and Escherichia coli in a co-culture using an electrode as electron acceptor." Scientific reports 5 (2015).