The protein fraction from wheat-based dried distiller's grain with solubles (DDGS): extraction and valorization

Abstract

Nowadays there is worldwide interest in developing a sustainable economy where biobased chemicals are the lead actors. Various potential feedstocks are available including glycerol, rapeseed meal and municipal solid waste (MSW). For biorefinery applications the byproduct streams from distilleries and bioethanol plants, such as wheat-based dried distiller's grain with solubles (DDGS), are particularly attractive, as they do not compete for land use. Wheat DDGS is rich in polymeric sugars, proteins and oils, making it ideal as a current animal feed, but also a future substrate for the synthesis of fine and commodity chemicals. This review focuses on the extraction and valorization of the protein fraction of wheat DDGS as this has received comparatively little attention to date. Since wheat DDGS production is expected to increase greatly in the near future, as a consequence of expansion of the bioethanol industry in the UK, strategies to valorize the component fractions of DDGS are urgently needed.

Figure 1

Wheat DDGS composition and options for valorization of the different fractions.

Figure 2

The amino acid sequence of a glutenin from wheat showing a biased amino acid composition towards glutamine (35% of the total amino acid sequence highlighted in red), glycine (20% highlighted in green) and proline (13% highlighted in blue) The illustrated protein is from Triticum aestivum with the GenBank accession number: CAA27052.1. This example is 838 amino acids in length.