Use of rice husk supplemented with watermelon residue for the production of lignocellulolytic enzymes by pleurotus ostreatus

The post - harvest residue of rice (Oryza sativa) and watermelon (Citrullus lanatus) in the state of Tocantins, mainly in the region of Formoso do Araguaia, where the highest production of these products in the state is concentrated, may serve as a substrate for obtaining hydrolytic enzymes and oxidative stresses involved in the degradation of lignocellulosic materials by Pleurotus ostreatus grown in solid state. The main component of agricultural, forest and urban waste consists mainly of three types of polymers: cellulose, hemicellulose and lignin, such as laccase, manganese peroxidase and xylanase. Some microorganisms, especially fungi, produce enzymes capable of degrading lignocellulose by making available and breaking the constituent polymer chains, allowing the subsequent conversion of the molecules originating in materials of interest (bioconversion). The use of the basidiomycete P. ostreatus showed great potential for the enzymatic degradation of these residues, at different moisture contents and without the need for any supplementation. The medium based on watermelon peel and rice yielded high activity of enzymes with great potential for industrial use, especially laccase (48.0 ± 0.35 UL -1 dry substrate after 25 days of culture) and manganese peroxidase (8.00 ± 0.23 Ug -1 substrate after 25 days of culture).