The cell growth based AFM micrographs confirmed the exfoliation to be controlled by yeast cell growth where the graphite was considerably thinned down to few layers within few days of incubation. In addition, we suspect that the exfoliation will continue if thinner flakes are subjected to a fresh growing yeast. The thickness-to-time plot revealed a significant reduction in the thickness within 4 hours of incubation which corresponded to the logarithmic growth phase of dry yeast cells (Supplementary Fig. ). Further thinning of the sheets was observed where the reduction was observed to reach ~10 nm in one week. The uniformity of the exfoliation process was established by estimating the standard deviation in the thickness of the prepared graphene with respect to incubation time where increasing incubation time led to the exfoliated structure with comparable thickness. The action of yeast cells on the edges of the prototype, graphite, was examined by studying the lateral dimension and aspect ratio of the exfoliated structure with respect to increasing incubation time with yeast cells, Supplementary Fig. . The lateral dimension of the obtained layers was significantly reduced with increasing time which suggests the tearing the graphite from the edges by the yeast cells as shown in SEM micrographs. The aspect ratio of the obtained exfoliated flakes was observed to be increasing for up to 6 h of incubation. This indicated the formation of extremely thin graphene structure suggesting higher rate of thinning from within the layers of graphite in comparison to rate observed for delayering from the edges (out of plane for [001]). The observation can be attributed to the feasibility in overcoming the Van der Waals bonding in comparison to covalent bonding. The TEM analyses of the prepared few layer graphene has been elaborated in the supplementary section, supplementary Fig 3 . The functional and optical characterization of the exfoliated graphene layers was revealed by spectroscopic analyses. The UV absorption study of the prepared graphene, Fig. , demonstrated a characteristic peak at ~270 nm, assigned to π → π * transition of aromatic C-C bonds. The spectra were monitored with respect to the incubation period which showed the highest absorption to occur after 1 week of incubation with yeast cells, confirming the AFM analyses. The surface functionalization state of the obtained graphene flake was studied using FTIR and shown in Fig. ). The distinct peaks were obtained at ~1630 and 1210 cm -1 which corresponded to the functional groups i.e., carboxylic and phosphate groups arising from yeast cell wall, thus suggesting the yeast cells based functionalization of the exfoliated graphene. Post functional state analyses with FTIR spectroscopy, the exfoliated graphene was further characterized using Raman spectroscopy to identify the impact of yeast cells' growth parameters on its lattice and structural properties. The yeast cells' concentration in the suspension for graphite thinning was optimized by plotting the Raman spectra, Fig. ), for a range of yeast cells' concentration (0-0.5% (w/v)). The significant change in the integrated area ratio (AD/AG) suggests the presence of functionalized graphene sheets owed to the yeast cells mediated exfoliation of graphite into graphene as already been established by FTIR study.