Recent developments in microbial degradation of crop residues: a comprehensive review

Currently, management and disposal of crop residue is a complicated task due to its recalcitrant nature and huge quantity. Currently, many of the developing countries majorly depend on traditional approaches such as open fire burning, dumping and mulching to manage these crop residue or the agricultural wastes. But these methods especially the open fire burning appears as a major factor for the global warming, environmental pollution, which adversely affect the human health. In this context to manage the crop residue or the recalcitrant material in sustainable and ecofriendly manner is an immediate need. Microbial based biodegradation emerges as one of the most efficient approach to manage huge amounts of crop residues. Although, plenty of publications are present, which describes the methods and microorganisms involved in degradation of crop residues, both ex situ as well as in situ conditions. However, in-depth analyses, optimization and refinement is required to boost the efficiency of such techniques for the microbial deconstruction of lignocellulose. In this review, we attempt to collate and analyze the recent developments in microbial degradation of crop residue at various levels such as composting, manipulation of soil factors, with recent advances made with the help of metagenomics, metatranscriptomics and genetic engineering. Although, understanding of the processes involved in decomposition can be achieved by analyzing the metagenome as well as metatranscriptome data associated with decomposing biomass. This information can be used for identifying efficient organisms and manipulating the microorganisms to accelerate the degradation and valorization of the products.