Earthworm stocking density regulates microbial community structure and fatty acid profiles during vermicomposting of lignocellulosic waste: Unraveling the microbe-metal and mineralization-humification interactions. (January 2023)

• Record Type: Journal Article
• Authors: Devi, Jinnashri; Pegu, Ratul; Mondal, Himadri; Roy, Rashmi; Sundar Bhattacharya, Satya
• Is Part Of: Bioresource technology. Volume 367(2023)
• Publication Date: 2023-01
• Subjects: Stocking density -- Earthworms -- Lignocellulosic waste -- PLFA-assay -- Metal removal; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2022.128305
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Thin earthworm stocking promotes degradation of lignocellulosic vermibeds. 5–7 earthworm/kg stocking improved fecundity, humification, and NPK availability. Thin Eisenia stocking and dense Eudrilus stocking enriched microbial-PLFA profiles. Metal removal efficacy of Eisenia fetida enhanced by thin initial stocking density. Microbial-PLFA strongly regulated metal availability in lignocellulosic vermibeds. Abstract: Earthworm-induced microbial enrichment is the key to success in vermitechnology, yet the influence of initial earthworm stocking density on microbial community profiles in vermibeds is unknown. Therefore, vermicomposting of lignocellulosic feedstock was performed with different stocking densities of two earthworms ( Eisenia fetida and Eudrilus eugeniae ) compared with composting. Eventually, earthworm growth, microbial (activity and community profiles), and physicochemical dynamics were assessed. The earthworm population significantly increased under low stocking, while denser stocking (15/kg) was stressful. The XRD-based crystallinity assessment revealed that comminuting efficiency of Eisenia and Eudrilus was prudent at 7 and 10 worm/kg stockings, respectively. Moreover, the 5 and 7 worm/kg stockings effectively mobilized microbial activity, promoting NPK-mineralization and C-humification balance. Correlation statistics indicated that earthworm stocking density-driven microbial community shift and fatty acid profiles strongly influenced metal removal in vermibeds. Hence, the findings implied that 5–7 worm/kg stockings of earthworms produced high-quality sanitized vermicompost.