Agri-Food Waste Valorization through Dairy Whey Fermentation for Sustainable Tomato Production

The dairy industry generates large volumes of whey, a nutrient-rich by-product that poses
serious environmental challenges if discarded untreated. This study explores the valorization
of raw (LC) and pasteurized (LP) bovine whey through spontaneous anaerobic fermentation
driven by native microbiota, aiming to produce natural biostimulants and biofertilizers for
sustainable agriculture. The fermented derivatives (LC.FN and LP.FN) were characterized
to assess their physicochemical, biochemical, and agronomic properties.
Fermentation induced a marked decrease in pH and enhanced the accumulation of organic
acids, peptides, and free amino acids, confirming substantial biochemical transformation of
the substrate. In germination assays using Solanum lycopersicum L. (cv. Campbell 33),
fermented whey treatments significantly improved root and shoot elongation, germination
percentage, and seedling biomass compared with the control.
Under greenhouse conditions, both root irrigation and foliar spraying with fermented whey
(1% v/v) promoted vegetative growth, increasing shoot and root length, fresh and dry
biomass, and leaf area. Photosynthetic pigment content (chlorophyll a, chlorophyll b, and
carotenoids) also rose markedly, indicating enhanced physiological activity. Moreover, repro
ductive traits such as flower and fruit number exhibited significant improvements. Statistical
validation (ANOVA, Dunnett’s, and Tukey’s tests; α = 0.05) confirmed the reliability of these
effects.
Overall, this study demonstrates that whey fermentation represents a dual-benefit process:
reducing the environmental footprint of dairy effluents while generating bioactive, low-cost
formulations capable of stimulating plant growth and productivity. These findings posi
tion fermented whey as a promising component in circular bioeconomy strategies and an
eco-efficient alternative to chemical inputs in crop management