EXTRACTION AND PHYSICOCHEMICAL CHARACTERIZATION OF WHEY PRODUCED FROM COLA NITIDA LEAVES

Kola (Cola nitida) leaves are widely known for their ethnobotanical uses, yet their by- products remain underexplored as sources of bioactive compounds for environmental applications. Fermentation of plant-derived substrates often enhances their physicochemical profile, making them useful in biostimulation processes that support microbial activity for pollutant degradation. Against this background, this study investigated Cola nitida whey, focusing on its extraction, fermentation behavior, and nutrient composition, with the aim of assessing its potential application as a bioremediant. Fresh kola leaves were processed through washing, grinding, boiling, and filtration to obtain whey, which was digested with nitric acid and subjected to physicochemical analysis. Parameters evaluated included pH, electrical conductivity (EC), moisture content, total organic matter (TOM), total organic carbon (TOC), nitrate, phosphate, nitrogen, phosphorus, and potassium. Results showed dynamic changes across the five- week fermentation period. pH decreased initially from 5.29 in Week 1 to 5.18 in Week 3 before rising to 6.01 in Week 5, while EC steadily increased from 1595.50 to 2129.50 µS/cm, reflecting ionic release. Moisture content rose from 92.08% to 94.09%, whereas TOM and TOC increased overall, with TOM ranging from 54.06 to 106.55% and TOC from 31.36 to 61.80%. Nutrient levels indicated progressive mineralization: nitrate rose from 174.16 to 1152.36 mg/kg, phosphate from 411.67 to 971.81 mg/kg, nitrogen from 39.56 to 261.06 mg/kg, and phosphorus from 122.75 to 295.46 mg/kg. Potassium fluctuated but stabilized at 2.55 mg/kg by Week 5. These findings suggest that kola-leaf whey develops enriched organic and mineral content during fermentation, creating a nutrient-rich medium favorable for microbial proliferation. The shift toward near-neutral pH at later stages further supports microbial activity, while the elevated nitrate and phosphate levels highlight its suitability as a low-cost, plant-derived stimulant for bioremediation, although regulated application is recommended to minimize eutrophication risks.