Valorization of baobab fruit shell as a filler fiber for enhanced polyethylene degradation and soil fertility

Abstract Baobab fruit shell waste (BFS) is well known for its high contribution to the sustainable green environment. This study investigated BFS as a filler fiber mixed with polyethylene (PE) for its degradation behavior and its potential as a nutrient source for soil. Screened BFS was crushed and blended with PE at four levels (PE/BFS: 100/0, 95/5, 90/10, and 85/15 wt%). Extruded mixtures were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), and diffusive gradients in thin films (DGT), along with a soil burial test, following standard methods. SEM-EDS results indicated an enrichment of blends with trace essential nutrients (Na, Mg, P, K, Ca), which are crucial for metabolism, protein stabilization, and enhancing denitrifiers in microbial cells. TGA and mechanical studies indicated that PE/BFS degraded at a faster rate (starting at 249.1 °C) than the control (376.8 °C). The elongation at break and tensile strength of pure PE decreased with increased BFS content, with elongation at break showing a sharper reduction ( p < 0.05). DGT results confirmed the presence of beneficial compounds and nutrients in the soil with BFS blends, suggesting its potential as a plant nutrient source. It is crucial to further valorize BFS and organic waste into value-added products for environmental sustainability.