Effects of light, CO₂ and inhibitors on the current output of biofuel cells containing the photosynthetic organism Synechococcus sp

Abstract

The current output of the biofuel cells containing a marine alga, Synechococcus sp. and an electron transport mediator, 2-hydroxy-1 ,Cnaphthoquinone (HNQ) was increased under illumination and in the presence of CO,. The inhibitory effects of carbonyl cyanide m-chlorophenylhydrazone (CCCP), 3-(3,4-dichlorophenyl)-l, 1 -dimethylurea (DCMU), 2,5-dibromomethylisopropyl-pbenzoquinone (DBMIB), phenylmercury acetate (PMA) and N,N-dicyclohexylcarbodiimide (DCCD) on the output current of fuel cells run in the light suggested that HNQ accepts electrons mainly at the site of ferredoxin-NADP' reductase (FNR) in the electron transfer chain. The inhibition of light-induced generation of current output by CCCP indicates that the current is derived from photosynthetic oxidation of water. Endogenous glycogen in algae is required to sustain a steady current output from the fuel cells.

Photosynthetic microbial fuel cells with positive light response

“…This work provided the first illustration that a positive light response (i.e., immediate increase in current upon illumination) could be achieved in a PMFC. An immediate positive light response is consistent with the idea that electrons could be supplied directly by the photosynthetic electron-transfer chain, and not derived only from the respiratory transfer chain or through oxidation of hydrogen (Yagishita et al, 1993). These studies, however, were performed using a two-chamber PMFC with potassium ferricyanide in cathode chamber, and phosphate buffer and exogenous electron shuttle in the anode chamber.…”

Photomicrobial Solar and Fuel Cells

“…Later, it was shown for the cyanobacterium Synechococcus sp. that HNQ is reduced by the ferredoxin-NADP þ reductase (FNR) [22].…”

Photoelectrochemical cells based on photosynthetic systems: a review

“…Various cyanobacteria were used in most effective PMFCs reported (Yagishita et al, 1993;Torimura et al, 2001;Pisciotta et al, 2010). In particular, the ability of the cyanobacteria Nostoc sp, in generating a photocurrent was investigated using various electrochemical methods.…”

“…Since the structure of the BQ is similar to that of PQ, the addition facilitated electron transfer from the PS2 to the MWCNT (Sekar et al, 2014). Previously, mediators such as BQ, 2,6-dimethyl-1-benzoquinone (DMBIB), and 2-hydroxy-1,4-naftahinon (HNQ) were also used for accepting the electrons from the cyanobacterial photosynthetic ETC (Yagishita et al, 1993;Torimura et al, 2001). …”