Fermentation (Dec 2023)

Microbial Fermentation of the Water-Soluble Fraction of Brewers’ Spent Grain for the Production of High-Value Fatty Acids

  • Stefano Serra,
  • Paola D’Arrigo,
  • Letizia Anna Maria Rossato,
  • Eleonora Ruffini

DOI
https://doi.org/10.3390/fermentation9121008
Journal volume & issue
Vol. 9, no. 12
p. 1008

Abstract

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Brewers’ spent grain (BSG) constitutes the primary by-product of the brewing industry. The valorization of BSG from a circular economy perspective is of high industrial interest. The objective of this study was the exploitation of BSG for the microbial production of branched-chain fatty acids (BCFAs) and polyunsaturated fatty acids (PUFAs), representing two different classes of high-value fatty acids (FAs). In the present study, this waste material underwent treatment with hot water in an autoclave and the resultant extract was utilized for the preparation of a novel liquid medium (BSG medium) to be employed for microbial fermentation. Screening and subsequent scaling-up experiments confirmed the suitability of the BSG medium to support the microbial production of various high-value FAs. In particular, Streptomyces jeddahensis and Conidiobolus heterosporus could be employed for BCFAs production, Pythium ultimum and Mortierella alpina could be used to provide cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and arachidonic acid (ARA), whereas Mucor circinelloides, when grown in a BSG medium, was able to accumulate γ-linolenic acid (GLA).

Keywords