Rice (Oryza sativa L.) straw, an agricultural waste of high yield, is a sustainable source of fermentable sugars for biofuel and other chemicals. However, it shows recalcitrance to microbial catalysed depolymerization. We herein describe development of thermotolerant microbial consortium (RSV) from vermicompost with ability to degrade rice straw and analysis of its metagenome for bacterial diversity, and lignocellulolytic carbohydrate active enzymes (CAZymes) and their phylogenetic affiliations. RSV secretome exhibited cellulases and hemicellulases with higher activity at 60 °C. It catalysed depolymerization of chemical pretreated rice straw as revealed by scanning electron microscopy and saccharification yield of 460 mg g⁻¹ rice straw. Microbial diversity of RSV was distinct from other compost habitats, with predominance of members of phyla Firmicutes, Proteobacteria and Bacteroidetes; and Pseudoclostridium, Thermoanaerobacterium, Chelatococcus and Algoriphagus being most abundant genera. RSV harboured 1389 CAZyme encoding ORFs of glycoside hydrolase, carbohydrate esterase, glycosyl transferase, carbohydrate binding module and auxiliary activity functions. Microorganisms of Firmicutes showed central role in lignocellulose deconstruction with importance in hemicellulose degradation; whereas representatives of Proteobacteria and Bacteroidetes contributed to cellulose and lignin degradation, respectively. RSV consortium could be a resource for mining thermotolerant cellulolytic bacteria or enzymes and studying their synergism in deconstruction of chemically pretreated rice straw.

Chickpea (Cicer arietinum L.) can obtain much of its N requirement through nitrogen fixation, but plant productivity also relies on N fertilization. Nitrogen capture from fertilizers by the plant is highly inefficient and can have a negative impact on the environment. Plant growth promoting rhizobacteria (PGPR) can improve efficiency of N fertilizer use and support optimum plant growth under low N input to soil. Chickpea plants were grown in pots and treated with low and optimum N input supplemented with PGPR. Bacteria isolated from chickpea rhizosphere exhibited potential growth promoting production of ammonia, indole acetic acid and phytase and solubilization of inorganic phosphate and zinc. A PGPR strain, identified as Cedecea davisae RS3, was selected by principal component analysis and its effect on plant growth promotion evaluated in chickpea plants under N-appropriate (N⁺), N-deficit with RS3 (N⁻RS3) and N-appropriate with RS3 (N⁺RS3) treatments. Overall performance of chickpea plants grown under N⁻RS3 was better than that of N⁺ and N⁺RS3 plants. The improved performance under N-RS3 could be related to enhancement of root nodulation and nitrogenase activity. The PGPR with N-RS3 might be used to obtain sustainable production of chickpea under reduced N.