From Agro-Industrial Waste to Biofertilizer: A Semi-Review of Fermented Tofu Wastewater and Its Agricultural Potential

Abstract

Tofu wastewater from agro-industrial activities contains high organic and nutrient loads. Presenting both environmental challenges and resource recovery opportunities, this semi-reviewed paper complemented by experimental data, evaluates the viability of fermented tofu liquid waste as a eco-friendly liquid organic fertilizer. Microbial fermentation using Effective Microorganisms (EM4) and optimized sugar supplementation converted complex organic matter into bioavailable phosphorus while stabilizing pH and reducing odour. The fertilizer was tested on chili plants (Capsicum annuum L.) to evaluate its effect on their growth. Experimental result showed that fermentation for 14 days with 75 g sugar maximized nutrient solubilization and enhanced early vegetative growth, specifically root development and stem elongation. Valorisation of this waste stream aligns with circular bioeconomy principles by recycling nutrients, reducing synthetic fertilizer dependency, and closing nutrients loops. Implementing this framework directly addresses several SDGs: SDG 2 by boosting food production, SDG 6 through proper wastewater treatment, SDG 12 via sustainable waste repurposing, and SDG 13 by generating low-carbon biofertilizers. The study highlights the feasibility of integrating tofu-waste-derived liquid organic fertilizers into smallholder and commercial agricultural systems, emphasizing the need for standardized fermentation protocols, microbial safety assessment, and field-scale validation.