Exploratory Assessment of Some Regional Food Wastes as Potential Biofertilizers: Effects on Vegetative Growth and Phytochemical Profile of Phaseolus vulgaris L.

Developing innovative green strategies regarding the integration of by-products and waste from the food industry for sustainable agriculture and a circular economy represents a current challenge of great interest. The present exploratory study evaluated four regional potential food-waste-derived biofertilizers under controlled greenhouse conditions. Eggshell powder (EGP), whey, sea buckthorn pomace powder (SBPP), and grape pomace hydroalcoholic extract (GPHAE), used separately or in combination, were tested to observe the response of a relevant crop, Phaseolus vulgaris L. var. communis Auria Bacăului, in terms of vegetative growth parameters and its phytochemical profile. Plant biometric parameters, some representative metabolites (chlorophyll, carotenoids, polyphenolic compounds, and amino acids), and antioxidant activity were investigated using appropriate analytical techniques. The results demonstrated that bean plants grown on soil amended with EGP exhibit high biometric values, validating the efficacy of this by-product as a potential biofertilizer. The mixture of water and GPHAE used on the amended soils with EGP, and with EGP and SBPP, induces a positive effect on the total chlorophyll content accumulated in the bean samples (0.204–0.212 mg/g) compared to similar samples sprayed only with water. The mixture of water, whey, and GPHAE resulted in free amino acid accumulation in beans regardless of soil amendment. The highest synergetic effect on amino acid accumulation was found between this fertigation solution and the soil supplemented with EGP. The overall results of the present work confirm the potential of these regional food by-products and waste as biofertilizers, offering a dual solution for food industry waste management and sustainable agricultural development.