Chemical, biological, and metagenomic profile of biofertilizers containing native forest and whey microbiota and enriched with macronutrients and micronutrients.

BACKGROUND: Biofertilizers are gaining interest as sustainable nutrient sources that enhance nutrient and soil biological quality. The chemical, biological, and metagenomic profiles of biofertilizers produced from native forest microbiota and acidic whey, and enriched with macronutrients and micronutrients through anaerobic fermentation, were evaluated. RESULTS: Fermentation of the biofertilizer base over 4 days increased pH (3.0-3.8) and decreased oxidation-reduction potential (ORP, 178 to -173 mV), while electrical conductivity (EC) remained stable (3.7-4.1 mS cm-1). After enrichment with macronutrients and micronutrients, 35 days of fermentation, and formulation of the model nutrient solution (MNS), pH stabilized around 4.8, and EC decreased to 1.72 mS cm-1. Most biofertilizers, when enriched individually, maintained negative ORP values; however, the increase in ORP observed in the MNS (140 mV) suggests that incorporating the copper-enriched biofertilizer may have contributed to more oxidizing conditions. Biological analysis suggested enhanced nutrient transformation, as revealed by chromatographic complexity in most enriched treatments. The 16S rRNA gene amplicon-based metagenomic profiling showed higher amplicon sequence variant (ASV)-level richness and taxonomic diversity in MNS (592 ASV records and 57 resolved genera) than in the unenriched biofertilizer (342 ASV records and 41 resolved genera). At the genus level, both profiles shared a dominant taxonomic backbone but showed measurable differences in relative abundance patterns (Bray-Curtis = 0.266). Fermentative taxa, including lactic-acid-bacteria-associated genera and Clostridium, dominated both biofertilizers. CONCLUSIONS: Mineral-source fermentation by native forest microbiota modified the chemical environment, increased microbial diversity and complexity, and enhanced biological indicators of nutrient transformation; these changes suggest potential for increased nutrient bioavailability. © 2026 Society of Chemical Industry.