Browsing by Author "Amati, Allen"

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    Magnetite nano-catalyst enhanced microbial pretreatment of banana pseudostem for improved biogas production.
    (Busitema University, 2026) Amati, Allen
    The recalcitrant lignocellulosic structure of banana pseudostem limits its biogas yield, necessitating effective pretreatment. This study optimized nanocatalytic microbial pretreatment using magnetite (Fe₃O₄) nanoparticles and Pleurotus ostreatus to enhance delignification and subsequent biogas production from Ugandan banana pseudostem biomass. Physicochemical characterization revealed moisture content of 89.75%, volatile solids of 75.1% of total solids, a C/N ratio of 41.0, and lignocellulosic composition of 35.5% cellulose, 20.1% hemicellulose, and 13.2% lignin. Magnetite nanoparticles crystallite size 100 nm, showing spherical to octahedral morphology were synthesized via co-precipitation, and P. ostreatus inoculum 3.2 g/L dry mycelium was cultured. Central Composite Design optimization established optimal pretreatment conditions of 3.09% w/w magnetite and 13.14% v/w microbial inoculum, achieving 79.7% delignification with a statistically significant synergistic interaction (p < 0.05). Fourier Transform Infrared spectroscopy confirmed lignin peak reduction at 1510 cm⁻¹ and 1240 cm⁻¹, while X-ray diffraction and scanning electron microscopy validated structural disruption and increased surface porosity. The combined pretreatment produced 0.01997 m3 biogas per 100 g dry biomass which is 47% increase over untreated controls, with methane content of 68.3% and methane yield of 0.00018 m3 CH₄/g VS. Kinetic analysis using the modified Gompertz model revealed shorter lag phase of 2 days and higher maximum production rate 0.00416m3/day, confirming accelerated hydrolysis. The combined pretreatment achieved 59% of the theoretical maximum biogas yield. This green pretreatment technology, integrating nanocatalysis with fungal delignification, offers a sustainable pathway for valorizing banana agricultural residues into renewable energy, with direct applicability to existing fiber decortication operations.