Transforming bio-waste into value-added products mediated microbes for enhancing soil health and crop production: Perspective views on circular economy

Unprecedented increasing of human population has led to the huge production of bio-wastes which is a rich source of plant nutrients. These bio-wastes consist of fundamental nutrients (e.g. phosphorous, nitrogen, and potassium) which can play a crucial role in protecting agriculture sectors from the adverse effects derived from synthetic fertilizers. Reusing bio-waste materials originating from agricultural waste, animal waste, and sewage sludge can aid in the recovery of nutrients as well as the development of products with value, in order fostering a circular economy. Waste valorization is the process of converting waste into valuable products for the enhancement of soil fertility and sustaining agricultural plant growth. Microbes and biological systems offer sustainable bioconversion mechanisms to convert bio-waste into valuable bio-products. By utilizing bio-based fertilizers derived from bio-waste, agricultural production can be increased while mitigating the negative environmental impact caused by synthetic fertilizers. These microbes are sourced from nature and cultivated in the laboratories which are further incorporated into suitable carrier materials for application in the soil. More research is needed to explore their field-level applications of bio-based fertilizers, which are supported based on 155 publications included in this study, to maintain agricultural sustainability and productivity. However, the interplay between plant and microbes must be carefully considered to ensure an optimal result in the field, sometimes requiring artificial augmentation. Therefore, the present review emphasizes the development of bio-based fertilizers through cutting-edge technology, microbial utilization, optimization for a circular economy, which opens new horizon for bio-waste minimization and its resource utilization.