Kinetic Modeling of Ethanol Batch Fermentation by Escherichia Coli FBWHR Using Hot-Water Sugar Maple Wood Extract Hydrolyzate as Substrate

Yang Wang,Shijie Liu

doi:10.3390/en7128411

Abstract

A recombinant strain of Escherichia coli FBWHR was used for ethanol fermentation from hot-water sugar maple wood extract hydrolyzate in batch experiments. Kinetic studies of cell growth, sugar utilization and ethanol production were investigated at different initial total sugar concentrations of wood extract hydrolyzate. The highest ethanol concentration of 24.05 g/L was obtained using an initial total sugar concentration of 70.30 g/L. Unstructured models were developed to describe cell growth, sugar utilization and ethanol production and validated by comparing the predictions of model and experimental data. The results from this study could be expected to provide insights into the process performance, optimize the process and aid in the design of processes for large-scale production of ethanol fermentation from woody biomass.

Highlights

With depleting fossil energy sources, increased oil prices and environmental awareness, more public attention has been drawn to the development of alternate forms of chemicals, materials, and energy [1,2].Ethanol is attractive due to the widespread use as alternative liquid fuel and other fine chemicals such as acetaldehyde and 1,3-butadiene [3], and has been mostly produced by fermentation from feedstocks such as corn and sugarcane [4]
The hot-water sugar maple hemicellulosic wood extracts hydrolyzate used in this study contained six monosaccharides, primarily xylose, and minor amounts of glucose, mannose, arabinose, galactose, and rhamnose and other compounds, such as phenolics and aromatics [7]
E. coli FBWHR, which was used in this kinetic and modelling fermentation studies

Summary

Introduction

With depleting fossil energy sources, increased oil prices and environmental awareness, more public attention has been drawn to the development of alternate forms of chemicals, materials, and energy [1,2].Ethanol is attractive due to the widespread use as alternative liquid fuel and other fine chemicals such as acetaldehyde and 1,3-butadiene [3], and has been mostly produced by fermentation from feedstocks such as corn and sugarcane [4]. Woody biomass is the most abundant organic source on Earth, with annual production in the biosphere of about 5.64 × 1010 Mg-C [7,8,9]. Hemicellulose containing both hexoses (glucose, galactose, mannose, rhamnose) and pentoses (xylose and arabinose), compromises up to 40% of the carbohydrates content of woody biomass and currently represents the largest polysaccharide fraction wasted in most cellulosic ethanol pilot and demonstration plants around the world [10] and even in corn ethanol plants [6], which would be the largest potential supply to provide ethanol in a world thirsty for liquid transportation fuel

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