Team:LZU-China/wetlab4

         We constructed a pollutant substrate(PNP) bio-sensor coupling riboflavin synthetic gene cluster, the genetically modified E.coli can secrete riboflavin when added PNP in MFC anode medium.Riboflavin is a efficient redox mediator as well as a stimulator of MFC. We created a novel MFC devices and built a quantitative monitor system of PNP via measuring voltage increment.

          It’s reported that Shewanella, a well-known star of electricity-producing bacteria family, can secretes riboflavin that mediate extracellular electron transfer (Marsili et al., 2008) , additionally, this amazing bacteria can produce electrically conductive pilus-like appendages called directly transfer electric charge by touching relative remote anode material(Gorby et al., 2006) . So we buy standard bacteria strain, Shewanella oneidensis strain MR-1, from China Center of Industrial Culture Collection, CICC.

Luria-Bertani (LB) broth was inoculated with S. oneidensis strain MR-1 and incubated aerobically at 30 °C for 5 days with shaking at 200 rpm. After assembling the MFC (described below) devices, 2 mL of MR-1 culture was transferred to a sterile MFC anode chamber, as well as 28ml sterile anode medium and lactate was added (20 mM) to ensure excess electron donor. Anode medium contained (per liter): 0.46 g NH4Cl, 0.225 g K2HPO4, 0.225 g KH2PO4, 0.117 g MgSO47H2O, 0.225 (NH4)2SO4, plus 10 ml of a mineral mix (containing per liter: 0.1 g MnCl24H2O, 0.3 g FeSO47H2O, 0.17 g CoCl26H2O, 0.1 g ZnCl2, 0.04 g CuSO45H2O, 0.005 g AlK(SO4)212H2O, 0.005 g H3BO3,0.09gNa2MoO4, 0.12 g NiCl2, 0.02 g NaWO42H2O, and 0.10 g Na2SeO4). Medium was adjusted to pH 7, sparged with oxygen-free N2, anode was sealed with white latex gasket.

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