Integrated Valorization of Banana Leaves and Sugarcane Bagasse into Oyster Mushrooms and Biofertilizer: Advancing a Circular Bioeconomy Approach

Abstract

The increasing generation of lignocellulosic agricultural residues presents both an environmental challenge and an opportunity for resource recovery within the circular bioeconomy. In Tanzania, banana leaves and sugarcane bagasse are among the most abundant biodegradable wastes generated from agricultural activities, local markets, and sugarcane juice vendors. These residues are commonly disposed of through open dumping or burning, contributing to greenhouse gas emissions, environmental pollution, and the loss of valuable biomass resources. This study investigated an integrated biomass valorization strategy that converts banana leaves and sugarcane bagasse into edible oyster mushrooms and nutrient-rich biofertilizer through a circular resource recovery pathway. Four substrate treatments were evaluated for physicochemical properties, mushroom growth, yield, nutritional quality, and spent-substrate compost quality. Substrate composition significantly affected performance. Although pure banana leaves supported the fastest mycelial colonization, the 2:1 banana-leaf-to-bagasse mixture produced the highest biological efficiency (60%), cap diameter (8.0 cm), and crude protein content (31.0%). It also generated the best compost, containing 1.5% nitrogen, 0.7% phosphorus, 2.0% potassium, and a 16:1 C:N ratio. The findings demonstrate a practical, low-cost strategy for Tanzania and comparable regions, reducing agricultural waste, producing nutritious food, improving soil fertility, supporting climate-smart agriculture, and advancing SDGs 2, 11, 12, and 13.