Study on the Sequential Combination of Bioethanol and Biogas Production from Corn Straw.

Katarzyna Kotarska,Anna Świerczyńska,Wojciech Dziemianowicz

doi:10.3390/molecules24244558

Abstract

The objective of this study was to obtain two types of fuels, i.e., bioethanol and biogas, in a sequential combination of biochemical processes from lignocellulosic biomass (corn straw). Waste from the agricultural sector containing lignocellulose structures was used to obtain bioethanol, while the post-fermentation (cellulose stillage) residue obtained from ethanol fermentation was a raw material for the production of high-power biogas in the methane fermentation process. The studies on obtaining ethanol from lignocellulosic substrate were based on the simultaneous saccharification and fermentation (SSF) method, which is a simultaneous hydrolysis of enzymatic cellulose and fermentation of the obtained sugars. Saccharomyces cerevisiae (D-2) in the form of yeast cream was used for bioethanol production. The yeast strain D-2 originated from the collection of the Institute of Agricultural and Food Biotechnology. Volatile compounds identified in the distillates were measured using gas chromatography with flame ionization detector (GC-FID). CH4 and CO2 contained in the biogas were analyzed using a gas chromatograph in isothermal conditions, equipped with thermal conductivity detector (katharometer) with incandescent fiber. Our results show that simultaneous saccharification and fermentation enables production of bioethanol from agricultural residues with management of cellulose stillage in the methane fermentation process.

Highlights

Starch raw materials or raw materials containing monosaccharides or disaccharides, i.e., fruit, vegetables, sugar beets, molasses, are used for biofuel production
According to the literature and preliminary research, it had been found that two-stage pretreatment, i.e., thermal hydrolysis in an alkaline environment and enzymatic hydrolysis, results in a high level of polysaccharide conversion
Enzymatic hydrolysis is reported as the most promising technique for converting lignocellulosic compounds into fermentable sugars such as glucose, which can be used as a cheap carbon source for ethanol production

Summary

Introduction

Starch raw materials (wheat, rye, maize, potatoes) or raw materials containing monosaccharides or disaccharides, i.e., fruit, vegetables, sugar beets, molasses, are used for biofuel production These raw materials are the basic food for humans and animals, their use for fuel purposes becomes competitive in relation to food production and is the reason for the increase of food prices. An alternative solution is the use of plant raw materials, which are by-products of the agricultural industry and contain lignocellulosic structures—corn straw, rye, barley, and wheat. They are available in larger quantities in comparison with grains and are able to be obtained more cheaply (waste from plant production) [1,2].

Objectives

Methods

Results

Conclusion