Vermicomposting with microbial amendment: implications for bioremediation of industrial and agricultural waste

Improved agricultural practices and rapid industrialization have led to huge waste generation, and the management of this waste is becoming a global concern. The process of vermicomposting has emerged as a method of choice for converting waste into useful manure, with evidence of increase in crop productivity. During vermi-composting, the collective activities of decomposing microorganisms and earthworms lead to the humification of organic/inorganic waste, thereby generating the final product called vermicompost. Different types of industrial wastes such as waste from paper industries, tanneries, sugar mills, and pulp and textile industries have been effectively converted to vermicompost and successfully used to improve plant growth. The vermicompost thus formed was also demonstrated to increase the production of pharmaceutically important plant secondary meta-bolites such as withanolides and polyunsaturated fatty acids. Microbial amendment with different bacterial and fungal strains during vermicomposting further proves to be beneficial by increasing nitrogen content, decomposing organic waste, providing aeration, and stabilizing the vermicompost. These microorganisms after passing through the earthworm's intestine increase in numbers in the vermicast, thus becoming enriched in vermi-compost, which is particularly important for their use as biofertilizers. The precise role of different microbial pretreatments in improving the quality of vermicompost generated from industrial and agricultural waste is, however, not completely understood. To fill this gap in knowledge, the present article aims to review published literature to highlight the potential of microbial amendment during vermicomposting for bioremediation of industrial and agricultural waste. Microbial pre-composting followed by vermicomposting emerges as an eco-friendly and economical approach for managing agricultural and industrial waste.