Microbial Reduction of Graphene Oxide by ‎Lactobacillus Plantarum

Here, we report that the reduced graphene oxide nanosheets were successfully synthesized using the ‎Lactobacillus plantarum biomass in a simple, environmentally friendly and scalable manner. We ‎produced graphene oxide by oxidization and exfoliation of graphite flakes with modified Hummer's ‎method and then reduced to reduced graphene oxide by using Lactobacillus plantarum biomass as a ‎reducing agent. Samples were characterized using Fourier transform infrared spectroscopy, X-ray ‎photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, ‎microconfocal raman spectroscopy and thermogravimetric analysis. After the reduction, we observed ‎that a considerable decrease in the oxygen containing functional groups of graphene oxide and an ‎increase in C/O ratio from 1.7 to 3.3 in which confirms sp2 graphitic carbons increase. Mainly, we ‎observed a significant decrease in epoxy and alkoxy functionalities. Furthermore, we determined an ‎exfoliation of graphene oxide to one or several (2-5) layers after the complete reduction. In addition to ‎reducing potential, Lactobacillus plantarum biomass also plays an important role as stabilizing agent; ‎here the reduced graphene oxide showed a good stability in water. The green synthesis reported in this ‎work is concerned with the production of high purity water-dispersible reduced graphene oxide using ‎Lactobacillus plantarum CCM 1904.‎