The first derivative of CV (DCV) helps to study the EET (Extra cellular KN-62 transfer) site of a redox species involved during the electron transfer on the redox voltammetric signature. The peak positions observed in the voltammogram indicates the involvement of redox mediators, which could be referred in the biological redox tower of electron donors and acceptors. The derivative voltammogram represents the rate of change of voltammetric current with respect to time and electrode potential E(di/dt) ( Naresh Kumar et al., 2014). The number of peaks were comparatively higher in DCV than the corresponding CV analysis. Six quasi reversible peaks were detected, each with a potential of 0.141, 0.094, −0.129, 0.177, 0.011 and −0.117 V corresponding to the involvement of Cytochrome-bC1, quinones and Fe–S proteins respectively ( Fig. 5b). All the redox shuttlers detected during DCV analysis are the membrane bound proteins of biocatalyst which act as electron carriers during the process. During microbial respiration, quinones not only serve as terminal electron acceptors, but also function as effective redox mediators during the transfer of electrons resulting in dye degradation.