OICC Press International Journal of Recycling of Organic Waste in Agriculture 2251-7715 15 3 2026 09 30 Impact of Bacterial Inoculation on Enzyme Activity in Vermicompost Derived from Various Vermi-beds 10.57647/ijrowa.2026.1503.28 EN Mitra Ebrahimi Department of Soil Science, Faculty of Agriculture, University of Tabriz, 29 Bahman Blvd., Tabriz, Iran Farshad Shakuri Department of Soil Science, Faculty of Agriculture, University of Tabriz, 29 Bahman Blvd., Tabriz, Iran Mohammad Reza Sarikhani Department of Soil Science, Faculty of Agriculture, University of Tabriz, 29 Bahman Blvd., Tabriz, Iran Zahra Delfruz Department of Soil Science, Faculty of Agriculture, University of Tabriz, 29 Bahman Blvd., Tabriz, Iran Nasser Aliasgharzad Department of Soil Science, Faculty of Agriculture, University of Tabriz, 29 Bahman Blvd., Tabriz, Iran Nosratollah Najafi Department of Soil Science, Faculty of Agriculture, University of Tabriz, 29 Bahman Blvd., Tabriz, Iran Journal Article 2026 09 30 Purpose: Vermicomposting can be enhanced by inoculating vermibeds with beneficial microbes, thereby improving its biofertilizer properties. This study examined how phosphate-solubilizing bacteria (Pseudomonas putida Tabriz) and nitrogen-fixing bacteria (Azotobacter sp.) influence enzyme activity in vermicompost produced from different organic substrates (litter, wheat straw, wood dust, and compost). Method: A mixture of cow manure and organic materials (1:8 w/w) was vermicomposted in 3-kg pots with Eisenia fetida earthworms. After four months, bacterial inoculants were introduced, and samples were analyzed at 0, 4, 7, and 10 months for acid phosphatase, urease, and cellulase activities. Results: Bacterial inoculation significantly increased enzyme activity, with peaks observed at 4–7 months. Overall, bacterial inoculation significantly increased enzymatic activity, with the highest values observed at 4 and 7 months after inoculation. Specifically, P. putida Tabriz enhanced cellulase and urease activities, while Azotobacter sp. improved phosphatase activity in the vermibeds. The highest enzyme activities were recorded in: compost (acid phosphatase, 1864 μg pNP/g.h), leaf litter (urease, 460 μg NH₄⁺-N/2h), and wood dust (cellulase, 1568 μg GE/g.24h). Enzyme activity gradually increased during the experiment but declined toward the end of the study period. Conclusion: Vermicompost effectively serves as a carrier for beneficial microbes, enhancing enzyme activity and soil health. This approach offers a sustainable way to improve agricultural productivity through biofertilization. Highlights Inoculation with P. putida and Azotobacter sp. significantly increases vermicompost enzyme activities. Peak enzyme activities are substrate-dependent: acid phosphatase in compost, urease in leaf litter, cellulase in wood dust. Enzyme activity peaks at 4 and 7 months post-inoculation, revealing optimal harvest times. A strategy integrating specific microbial inoculation with substrates enhances vermicompost quality for soil health.