סיכום: | 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, <i>Streptomyces jeddahensis</i> and <i>Conidiobolus heterosporus</i> could be employed for BCFAs production, <i>Pythium ultimum</i> and <i>Mortierella alpina</i> could be used to provide <i>cis</i>-5,8,11,14,17-eicosapentaenoic acid (EPA) and arachidonic acid (ARA), whereas <i>Mucor circinelloides</i>, when grown in a BSG medium, was able to accumulate γ-linolenic acid (GLA).
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