*2.5. Protein, Moisture, and Ash Determination*

Representative samples were drained off daily for protein content testing, using the method suggested by the AOAC (Association of Official Agricultural Chemists, Rockville, MD, USA) [33]. The protein percentage was calculated considering a conversion factor of 6.25. The dry weights, both of the fresh waste and fermentation samples, were calculated as steady weights after 2 h at 110 ◦C, using a Mettler PM 200 equipped with a Mettler LP16 IR balance (Mettler-Toledo GmbH, Laboratory & Weighing Technologies, Greifensee, Switzerland). Ash determination was carried out according to the AOAC method [33]. All samples were analyzed in triplicate.
