Stringari Alessandro, Tlais Ali Zein Alabiden, Tonini Stefano, Pinto Daniela, Mondadori Giorgia, Filannino Pasquale, Di Cagno Raffaella, Gobbetti Marco
Faculty of Agricultural, Environmental and Food Sciences, Free University of Bolzano-Bozen, Bolzano, Italy.
International Center on Food Fermentations, Bolzano, Italy.
Microb Biotechnol. 2025 Jun;18(6):e70171. doi: 10.1111/1751-7915.70171.
The large output of spent grains from the brewing industry presents environmental concerns but also offers promising nutritional and functional potential for valorization by researchers and industrial stakeholders. In this perspective, we investigated how non-conventional starters like Fructobacillus fructosus PL22 and Wickerhamomyces anomalus GY1 can drive the fermentation of brewer's spent grain (BSG), a solid by-product of the brewing industry, to enrich its portfolio of bioactive compounds. While sugar reduction was comparable between started- and unstarted-BSG, the effect of the fermentation became evident through the release of key microbial metabolites (lactic and acetic acids and ethanol). Both starters generated the highest number of unique peptides, with only one previously identified as antioxidant peptide found in BSG fermented with F. fructosus. During fermentation, most amino acids and phenolic compounds decreased, while BSG fermented with W. anomalus distinctly enhanced the release of Ala, Cys and GABA, and health-promoting phenolic compounds, such as gallic acid, gallocatechin, quercetin, naringenin, kaempferol, and isorhamnetin. These metabolic changes were associated with the enhanced antifungal and antioxidant properties, which in turn positively reflected on skin protection as shown by the increased proliferation of human keratinocytes, over-expression of the filaggrin (FLG) gene, and wound healing. The power of fermentation to revitalise BSG, giving it a second life chance through the improvement of its nutritional value and further multifunctionality, was demonstrated.
酿造行业产生的大量酒槽不仅带来了环境问题，也为研究人员和行业利益相关者提供了具有潜在营养和功能价值的利用前景。从这个角度来看，我们研究了诸如果糖杆菌PL22和异常威克汉姆酵母GY1等非常规发酵剂如何驱动啤酒糟（BSG）的发酵，啤酒糟是酿造行业的一种固体副产品，以丰富其生物活性化合物组合。虽然接种发酵剂和未接种发酵剂的啤酒糟在糖分减少方面相当，但发酵的效果通过关键微生物代谢产物（乳酸、乙酸和乙醇）的释放而显现出来。两种发酵剂都产生了最多数量的独特肽，在用果糖杆菌发酵的啤酒糟中仅发现一种先前鉴定为抗氧化肽的肽。在发酵过程中，大多数氨基酸和酚类化合物减少，而用异常威克汉姆酵母发酵的啤酒糟显著提高了丙氨酸、半胱氨酸和γ-氨基丁酸以及促进健康的酚类化合物（如没食子酸、表儿茶素、槲皮素、柚皮素、山奈酚和异鼠李素）的释放。这些代谢变化与增强的抗真菌和抗氧化特性相关，这反过来又对皮肤保护产生积极影响，如人类角质形成细胞增殖增加、丝聚蛋白（FLG）基因的过度表达和伤口愈合所示。证明了发酵使啤酒糟恢复活力的能力，通过提高其营养价值和进一步的多功能性，赋予它第二次生命机会。
