Rocchetti Gabriele, Fancello Francesco, Zara Giacomo, Hatami Forough, Coronas Roberta, Petretto Giacomo Luigi, Errico Michela, Lucini Luigi, Gallo Antonio, Mannazzu Ilaria
Department of Animal Science, Food and Nutrition, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
Department of Agricultural Sciences, Università degli Studi di Sassari, Viale Italia 39A, 07100 Sassari, Italy.
Food Res Int. 2025 Oct;217:116838. doi: 10.1016/j.foodres.2025.116838. Epub 2025 Jun 9.
To investigate the key metabolic pathways activated by Propionibacterium freudenreichii during the fermentation of second cheese whey (SCW), five strains previously selected for physiological, technological, and functional traits were used to ferment three SCW samples from dairies differing in technological level and whey cheese coagulation technique. Despite variations in SCW composition, all strains exhibited robust growth, reaching up to 9.65 Log₁₀ CFU/mL. Untargeted metabolomic analysis grouped both fermented and unfermented SCW samples into three main clusters, primarily driven by differences among the unfermented SCWs. This highlights the key role of SCW composition in shaping the metabolome, although the contribution of the different strains in the metabolomic profile of fermented SCW was also evident. The analysis further revealed the consistent accumulation of 45 metabolites across all fermented samples, including derivatives of vitamins B9 and B12, essential amino acids, as well as prebiotic and antioxidant compounds. Eleven metabolites were identified as potential biomarkers of SCW fermentation by P. freudenreichii, such as dopamine 4-sulfate and N-(1-deoxy-1-fructosyl) phenylalanine. Pathway analysis showed consistent enrichment of the "one-carbon pool by folate" pathway, along with glycine, serine, and threonine metabolism and vitamin B6 pathways. These findings demonstrate the metabolic versatility of P. freudenreichii in SCW and its suitability for SCW valorization through the production of nutritionally relevant compounds. Further experiments are currently in progress to assess the in vivo probiotic potential of the resulting microbial biomass and to confirm the suitability of fermented SCW as a sustainable and cost-effective food and feed additive.
为了研究费氏丙酸杆菌在二次奶酪乳清（SCW）发酵过程中激活的关键代谢途径，使用了先前根据生理、技术和功能特性选择的五株菌株，对来自技术水平和乳清奶酪凝固技术不同的乳品厂的三个SCW样品进行发酵。尽管SCW的组成存在差异，但所有菌株均表现出强劲的生长，菌数高达9.65 Log₁₀ CFU/mL。非靶向代谢组学分析将发酵和未发酵的SCW样品分为三个主要簇，主要由未发酵SCW之间的差异驱动。这突出了SCW组成在塑造代谢组中的关键作用，尽管不同菌株对发酵SCW代谢组谱的贡献也很明显。分析进一步揭示了所有发酵样品中45种代谢物的一致积累，包括维生素B9和B12的衍生物、必需氨基酸以及益生元和抗氧化化合物。11种代谢物被确定为费氏丙酸杆菌发酵SCW的潜在生物标志物，如硫酸多巴胺和N-(1-脱氧-1-果糖基)苯丙氨酸。通路分析表明，“叶酸一碳池”通路以及甘氨酸、丝氨酸和苏氨酸代谢和维生素B6通路一致富集。这些发现证明了费氏丙酸杆菌在SCW中的代谢多功能性及其通过生产营养相关化合物实现SCW增值的适用性。目前正在进行进一步的实验，以评估所得微生物生物质的体内益生菌潜力，并确认发酵SCW作为可持续且经济高效的食品和饲料添加剂的适用性。
