Determination of biochemical properties and bacterial diversity of compost and vermi̇compost obtained from different materials

In this study, the changes in the microbial (bacterial) diversity of compost (C) obtained from different materials with a 90-day incubation experiment and vermicompost (VC) obtained by adding Eiseina foetida species earthworms to these materials were determined using modern DNA technologies. In addition, chemical/biological/biochemical activity changes were revealed through some important chemical properties of β-glucosidase, alkaline phosphatase, and urease enzymes involved in metabolic processes during organic matter decomposition. When the results of the incubation experiment were evaluated, organic matter (OM), enzyme activity values, and bacterial counts of VC samples were higher than those of C samples. When evaluated in terms of waste types, it was determined that Grass-C and Grass-VC samples contained the highest values in terms of total N, exchangeable potassium, and β-glucosidase enzyme activity, and the Grass-VC sample also had higher alkaline phosphatase and urease enzyme activity values than other materials. It was observed that both C and VC forms of grass samples were superior in terms of properties compared to C and VC samples obtained from other farmyard manure, tea, and pomegranate peel wastes. It was determined that the important bacterial genera involved in the composting process were Chloroflexi and Gammaproteabacteria, while the important bacterial genera involved in the vermicomposting process were Bacteroidia, Desulfobacterota, Planctomycetota and Spirochaetota. The effect of conventional composting and vermicomposting on bacterial diversity was statistically significant. In addition, the effect of storage on the bacterial diversity of compost products obtained by different composting methods was found to be significant. When the levels in the relative bacterial abundance bar graph of the products obtained by conventional composting are compared, it is seen that the order is as follows: Tea>Farmyard manure>Grass>Pomegranate peel compost, while in the products obtained by vermicomposting, the order is as follows: Farmyard manure>Grass>Tea>Pomegranate Peel.