Biogenic Properties of Zoocompost Formed by the Black Soldier Fly Hermetia illucens Larvae during Bioconversion of Fruit and Vegetable Mixtures

The zoocomposts obtained by processing of commercial products (vegetables and fruit-and-vegetable mixtures) by Hermetia illucens larvae has been studied. The obtained zoocomposts are characterized by alkaline pH values (8.1–9.5) and a water content of 40–48%. The C/N ratio in vegetable zoocomposts is 19.5–20.1, while in the fruit-and-vegetable mixture this ratio is 13.6. All studied zoocomposts contained nitrogen, phosphorus, and potassium: the N : P : K ratio averaged 1.3 : 2.6 : 1. The composts are also characterized by high ammonium nitrogen content (up to 2500 mg N–NH3/100 g) and ability to fix nitrogen, indicating the presence of nitrogen-fixing bacteria. The numbers of microorganisms in zoocomposts ranged from 2.7 ± 0.5 to 11.9 ± 1.8 billion cells/g. According to the functional diversity, the microbial communities of the resulting zoocomposts are characterized as stable, sustainable microbial systems.