Comparative evaluation on the fermentative potential of single and assorted fruit and vegetable waste for production of bioethanol

Abstract

Fruit and vegetable waste (FVW) constitute a large part of municipal solid waste (MSW) and create significant environmental challenges by emitting the greenhouse gas methane. In contrast, these are a big source of fermentable sugar to produce bioenergy. Therefore, in this study, the Scanning Electron Microscopy (SEM), Attenuated total reflectance-fourier-transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and biochemical quantification of -cellulose and acid-insoluble lignin contents were carried out to compare fermentative potential between single (potato peel vs. orange peel) and assorted vegetable and fruit wastes. Collectively, the study indicates that assorted vegetable waste holds enormous biofuel potential by having low moisture content (6.78 %), moderately low decomposition temperature (Tmax: 299.36 {degrees}C), low crystallinity index (CrI: 19.12%), and high -cellulose contents (32.35 - 47.73 gm%) yielding high sugar (325.65 mg/g). The study also optimized several key fermentation parameters such as pH, sugar concentration and the time to produce bioethanol. It was observed that maximum production of ethanol (2.14%) was achieved at 28{degrees}C, at pH 6.3 with a higher initial sugar concentration of 200mg/g by using Saccharomyces cerevisiae strain NCIM 3594. This study supports the likely utility of unsorted vegetable waste to obtain bioethanol at a mass scale.