Bioethanol is a promising biofuel produced from agricultural wastes. The problem is that the bioconversion of cellulose to bioethanol takes a long time for excellent results. Predominantly, efficient enzymes and active microorganisms (yeast) can enhance the enzymatic saccharification and fermentation bioprocesses, respectively. The addition of nutrients and electron acceptors in form of nanomaterials was found to modify the bioenvironment and to biostimulate the microorganisms to accomplish the target bioprocesses efficiently. The objective of this investigation was to increase bioethanol production from agricultural wastes using nanomaterials. In this study, the bioethanol production from potato peels (as an example of agricultural wastes) was increased using ZnO nanomaterials and ZnO/g-C3N4 nanomaterials with the concentration of 5, 10, 15, 50, 100, and 150 mg/L each as well as the control (without the addition of nanomaterials). It was hypothesized that yeast treatment with nanomaterials (nutrients) leads to biostimulate yeast cells and increases cell activity. Consequently, it is hypothesized that these procedures increase bioethanol production from potato peels over a shorter Hydraulic Retention Time (HRT), i.e., residence time. It was found that the biostimulation of the fungi (yeast) Saccharomyces cerevisiae using 150 mg/L of ZnO/g-C3N4 nanomaterials generated the highest bioethanol concentration of 33.2% compared to all other treatments.