Biorefinery strategies for upgrading Distillers’ Dried Grains with Solubles (DDGS)

Abstract

Distillers' Dried Grains with Solubles (DDGS) is the major by-product of bioethanol and distillery plants. Due to its high content of proteins, water-soluble vitamins and minerals, DDGS has been long marketed as animal feed for livestock. EU legislation on liquid biofuels could raise the demand on bioethanol production in Europe, with a resulting increase in DDGS availability. DDGS contains a spectrum of complex organic macromolecules, particularly polysaccharides, in addition to proteins and vitamins, and its use as a starting raw material within a biomass-based biorefining strategy could lead to the development of multi-stream processes for the production of commodities, platform molecules or speciality chemicals, with concomitant economic benefits and waste reduction for bioethanol plants. The present review aims to outline the compositional characteristics of DDGS and evaluate its potential utilisation as a starting material for the production of added-value products. Parameters of influence on the chemical and physical characteristics of DDGS are discussed. Moreover, various pre-treatment strategies are outlined in terms of efficient DDGS fractionation into several added value streams. Additional processing steps for the production of medium and high added value compounds from DDGS are evaluated and their potential applications in the food and chemical industry sector are identified.

Changes in the arabinoxylan fraction of wheat grain during alcohol production

“…The differences in the degree of enrichment of TOT-AX and WE-AX between the commercial and laboratory scale DDGS samples probably results from the fact that the TS was sprayed back onto the DDGS in the commercial samples but not those prepared in the laboratory (Chatzifragkou et al, 2015). …”

“…Bioethanol is produced for two main purposes; traditionally as beverages or potable ethanol and more recently as a biofuel for automotive transportation (Chatzifragkou et al, 2015). The whole process is optimised to gain the highest possible yield of ethanol and the composition of DDGS varies depending on differences in the grains used, their composition, and variation in processing and production (Liu, 2011).…”

Open Fermentative Production of L-Lactic Acid from Distillers’ Grains by Lactobacillus casei CICC 6056

“…During grain-based ethanol production, a liquid fraction (thin stillage) and solid fraction (wet distillers' grains) are produced as byproducts of ethanol distillation and dehydration (Chatzifragkou et al 2015). The utilization of liquid distillery stillage as a substrate for lactic acid production has been extensively studied.…”

Microbial production of d‐lactic acid from dried distiller's grains with solubles

“…Moreover, the possible high levels of mycotoxins (three-fold compared to the original sources, i.e. As DDGS is also characterized by a high fibre content, it could potentially be used as an alternative carbon source for lactic acid fermentation [35]. In terms of fibre composition, DDGS is primarily composed of cellulose and hemicellulose, which mainly consist of the monosaccharides glucose, xylose and arabinose as the main sugars.…”

“…In terms of fibre composition, DDGS is primarily composed of cellulose and hemicellulose, which mainly consist of the monosaccharides glucose, xylose and arabinose as the main sugars. As DDGS is also characterized by a high fibre content, it could potentially be used as an alternative carbon source for lactic acid fermentation [35]. In commercial lactic acid production, glucose and corn starches have been widely used as substrates for fermentation.…”