New integrated processing of chicken bone waste using an enzymatic pretreatment and slow pyrolysis to produce green chemicals

The growing global demand for meat consumption, especially for poultry, has led to an increase in bone waste production that necessitates sustainable waste management strategies. This study proposes a new processing method for Chicken Bone Waste (CBW) and evaluates the reactant’s potential usage. The novel approach to this issue consists of the integration of an enzymatic pretreatment to CBW before being subjected to the pyrolysis process. First, the CBW were classically processed (CBW classic) and then underwent a novel enzymatic pretreatment that consisted of a mixture of protease, lipase, and amylase (CBW enzymes). The pretreated CBW were slowly pyrolyzed (10 °C/min) at temperatures between 500–900 °C. The increase in temperature led to a decrease in biochar yield of 45 ± 3 wt%. In addition, the biochar thermal stability increased with the augmentation of process temperature. The pyro-gas primary consists of CO₂ and ≥ C₂, CO, CH_4, and H₂. Higher process temperatures enhanced the production of ≥ C₂ and H₂. The maximum oil yields were 45.3 wt% (600 °C, CBW classic) and 38.5 wt% (500 °C, CBW enzymes). The bio-oil obtained from CBW enzymes at 600 °C exhibits higher yielding valuable compounds. Chemicals identified in the main groups can be used as scaffolds for plant protection products, waxes and polishes, fireproofing, textiles, rubber, jet fuel, biodiesel, etc. The study concludes that the novel integrated processing enhances the potential functionalities of pyrolysis products by producing green, renewable chemicals and resources.