Unravelling the importance of cold-adapted bacterial formulations in microbial community dynamics during in situ lemongrass residue valorization under cold conditions

The traditional ways to manage lemongrass waste (LGW) are indeed a major concern to mitigate its residing threats. Composting transforms LGW into nutrient-rich fertilizer, but low temperature hinders efficiency and compost quality. Bioprospecting cold-adapted microorganisms can help overcome these challenges. Despite the pressing need to reintegrate LGW into agricultural use and develop bacterial formulations for efficient biotransformation, there is a noticeable lack of research in this area. In the present study, the co-composting of kitchen waste with LGW was carried out by a cold-adapted bacterial consortium (CABC) consisting of twelve potential hydrolytic bacteria isolated from compost samples of Himalayan regions. Pit composting showed an accelerated decomposition in CABC-treated feedstock with higher nitrogen (3.01%), phosphorus (1.27%), and potassium (0.97%) content compared with control. The compost had 4.7 fertilizing and 5 clean index values, which classified it as the best quality with relatively high manurial potential. The treatment’s germination index was 63% higher than the control, affirming its non-toxic nature. Furthermore, the microbiome analysis revealed the dominance of Firmicutes, Proteobacteria, and Actinobacteria with higher species abundance and diversity during the maturation phase in CABC-treated compost compared to the control. The redundancy analysis showed a significant impact of moisture content, total organic carbon, and organic matter on bacterial communities. Functional potential analysis demonstrated an abundance of pathways related to degrading carbohydrates, proteins, and xenobiotics. Thus, the study underscores the effectiveness of the microbial intervention as a scientific and sustainable approach to recovering resources from aromatic plant residues, aligning with principles of cleaner production and the circular economy.