Extraction of cellulose from restaurant food waste

Abstract

Dietary fiber provides organisms with key nutrients and allows for transport of small molecules and metabolic products. Due to being biocompatible, sustainable, and positively influencing microbial communities, dietary fiber is utilized in the design of many materials in applications such as biomedical or agricultural. In this work, the feasibility of using randomly collected, mixed food waste from a local restaurant as a feedstock for extracting native cellulose is explored. The extraction procedure adapts previously utilized acid/base extraction procedures for the extraction of cellulose from single source fruit and vegetables and is tailored in both sequencing and concentration to account for the complexity of the feedstock. Despite being collected at random over a period of a year, extraction of cellulose from restaurant waste led to products with reproducible yield and chemical properties. FTIR spectroscopy and XRD revealed that the extracted cellulose has a chemical structure similar to commercially available cellulose products, but that the extracted cellulose was less crystalline, due to the presence of lower molecular weight species. Thermal analysis confirmed that the extracted cellulose contained lower molecular weight species and residual lignin, indicating a trade-off between yield and purity when using a complex feedstock such as mixed food waste in current extraction methodologies. Besides obtaining cellulose, other biopolymers, specifically pectin, hemicellulose, and lignin, can be recovered as viable products. This research demonstrates the feasibility of diverting real-world food waste streams from local restaurants to provide a sustainable, environmentally friendly feedstock for the extraction of biopolymers and to decrease the production of greenhouse gases in landfills.