Concerns about increasing energy demands as fossil fuel reserves are reduced and severe environmental concerns encourage the development of renewable alternative raw materials for fuels. One potential alternative to petroleum-based fuels is biodiesel.  This study is part of an overall objective to convert cellulose to bio-diesel, using cellulose-coated emulsion particles as micro-reactors for a cascade of biochemical reactions in a “one-pot” consolidated process. The overall goal is to utilize o/w emulsion particles coated by unmodified cellulose with a unique internal structure, integrated with enzymes and yeasts, to induce a cascade of biochemical process from cellulose to alcohol and to biodiesel. This study focuses on fabrication and characterization of the emulsion particles, in particular the cellulose coating shells’ characteristics (thickness, composition and porosity). Cryogenic-scanning electron microscopy (cryo-SEM) imaging reveals a unique multi-layer structure: an inner oil core surrounded by a shell composed of a porous cellulose gel which is encapsulated by an external cellulose shell. Small-angle x-ray scattering (SAXS) measurements provide a quantitative determination of the porous cellulose gel structure of the inner shell of the emulsion particle. The measurements indicate that the inner shell structure of the cellulose-coated emulsion droplets does not depend on the emulsification process and its parameters (homogenization pressure, the cellulose: oil ratio and the oil type). A suggested structural model of the inner shell of the emulsion droplet based on the SAXS measurements is an inhomogeneous porous hydrogel, consisting of pores, the size of which is a few tens of nanometers, embedded in a denser highly branched hydrogel with an apparent fractal structure suggestive of the cellulose aggregation process that occurs during regeneration from solution.  The unique structure of emulsion particles with an inner shell consisting of a porous cellulose hydrogel engulfing the hydrophobic core, can establish an innovative bio-reactor for one-pot processes for cellulose transformation to biodiesel.  It is expected that the results of this study, together with ongoing experiments of ethanol production by integration of cellulose-coated emulsion particles with yeasts and cellulytic enzymes will provide the complete transformation of cellulose to biodiesel.

Cellulose-coated oil in water emulsions with a porous cellulose hydrogel inner shell, as micro-reactors towards one-pot consolidated bio-processing of cellulose to biodiesel

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.