The production of plastic waste is responsible for several environmental problems that impact ecosystems and different areas of society. Due to its low cost and high durability, the material is used on a large scale that, together with poor waste management intensifies these problems. The biodegradation of plastic is performed by various microorganisms, such as Basidiomycota fungi of the genus Pleurotus, which, through their enzymatic machinery, can degrade synthetic polymers. Agro-industrial residues are generated excessively by agricultural and industrial activity and have low economic value because of their low utility. Despite this reduced economic value, these residues have high energy values that allow the development of fungi, representing alternative energy sources for biotechnological processes such as fermentation in solid state. In this way, the use of this energy potential through fungal growth enables the degradation of plastic materials and the production of mycelial biomolds, representing an alternative way to manage agro-industrial waste. In this study, a commercial strain of Pleurotus ostreatus was used, initially cultivated in Petri dishes with Sabouraud Agar. In the preparation of the Spawn, variations were made in the proportion of the substrate containing: 0-50% of oats, germ, and wheat bran. After sterilization at 121 ºC for 15 minutes, the packets were inoculated with four spots of the fungal strain. For the development of the biomold, different concentrations of substrates were used, varying from 60-65% malt residue, 15-20% corn stover, 5-10% agricultural gypsum, and 10-15% plastic waste in different combinations. The substrate that showed better fungal development of Spawn was 50% wheat germ, 50% wheat bran, and no flaked oats, incubated at 28 ºC for 7 days. The tested proportion that presented the best conditions for fungal development in the biomold was 60% malt residue, 20% corn stover, 10% agricultural gypsum, and 10% plastic waste. The use of waste from the brewing industry and non-recyclable plastic showed to be promising for the production of mycelial biomolds. Although the technique used in the study is still experimental, it showed great potential for a large-scale application that would employ a new use for plastic waste from materials of low economic value.