Low-density polyethylene polyethylene (LDPE) represents 20-30 % of the total solid waste generated worldwide and is of special importance due to its persistence in the environment and its negative impact on the environment, organisms and ecosystems. In response, the current management of LDPE waste is oriented towards the development of biodegradable alternatives such as oxo-biodegradable LDPE. These plastics incorporate pro oxidants that when exposed to high temperatures or UV radiation degrade to form polar groups such as hydroxyl and carbonyls that promote microbial degradation. Particularly, it has been shown that plasma treatment promotes the biotransformation of polyethylene by favoring the formation of these compounds. In general, it is of interest to find strategies that allow LDPE and oxo-biodegradable LDPE biodegradation since the conventional management of waste represent has negative consequences. Additionally, in Colombia, the agroforestry sector generates residues such as pine bark that slowly degrade and are not fully exploited. Consequently, it is found that ligninolytic fungi such as Pleurotus ostreatus are relevant for the biotransformation of pine bark and LDPE because of their ligninolytic enzyme systems which degrade a wide range of substrates. Therefore, this work presents a simultaneous process of bioconversion of lignocellulosic biomass and oxobiodegradable low density polyethylene sheets pretreated with O2 plasma using Pleurotus ostreatus. The present work had as a general objective to biotransform sheets of low density polyethylene (LDPE) and oxo-biodegradable LDPE pre-treated with O2 plasma using the fungus Pleurotus ostreatus. For this, the biotransformation of oxo-biodegradable LDPE and LDPE sheets pretreated with O2 plasma in modified Radha medium in wet chamber systems was evaluated. Subsequently, the effect of the addition of pine bark on the biotransformation of LDPE and oxo-biodegradable LDPE was determined and finally, the biotransformation of oxo-biodegradable LDPE was carried out in a 75-day microcosm system that incorporated a filling mixture comprised of pine bark (Pinus caribaea), paper towels and brewer’s spent yeast in a 3: 3: 1 ratio. The first specific objective was to evaluate the capacity of Pleurotus ostreatus to biotransform LDPE and oxo-biodegradable LDPE (Oxo: translucent biodegradable plastic and OxoC: biodegradable yellow plastic) previously subjected to a treatment with 100 % O2 plasma in modified Radha medium in wet chamber system during 150 days. Determining P. ostreatus colonization (mm), production of diffusible pigments (mm), oxidation of ABTS [2,2 'azino-bis- (3-ethylbenzathiazoline sulfate)] (mm) and ligninolytic enzymatic activity laccase, manganese peroxidase and lignin peroxidase (U/kg). For the LDPE, changes in the contact angle were determined as an indicator of the decrease in the hydrophobicity of the polymer, roughness, functional groups of the LDPE as well as colonization. It was possible to report growth, ligninolytic activity and polymer changes in both the LDPE and oxo-biodegradable LDPE by P. ostreatus. Particularly, increased growth of P. ostreatus (3876 mm2), enzymatic activity of manganese peroxidase (512 U /kg), decrease in hydrophobicity (67.86%, p <0.050) and decrease in functional groups CH3 and CH2 (2900 cm- 1 and 2800 cm-1) was observed in the Radha medium with oxo-biodegradable LDPE translucent Oxo. In general, the results presented evidence of the biotransformation of LDPE and oxo-biodegradable LDPE that has been subjected to plasma in the modified nutrient Radha medium by the activity of the fungus P. ostreatus. As part of the second specific objective, the effect of the addition of composted pine bark and Radha medium on the biotransformation of LDPE and oxo-biodegradable LDPE (Oxo and OxoC) by P. ostreatus was evaluated. For this, a physicochemical characterization of the substrate and a colonization test were carried out to evaluate the biomass production and ligninolytic activity of P. ostreatus. As well as changes in hydrophobicity, roughness, functional groups and colonization of LDPE and oxo-biodegradable LDPE. it was possible to show that P. ostreaus produces biomass (153.29 g /kg), has ligninolytic activity laccase (6610 U/kg), lignin peroxidase (24003 U/kg) and manganese peroxidase (1890 U/kg) (p < 0.050) when using the modified Radha medium as nutrient pulses during 60 days. Additionally, P. ostreatus generates significant changes in oxo-biodegradable plastic Oxo: allows a decrease in hydrophobicity of 86.2 %, decrease in functional groups CH3 and CH2 (2900 cm-1 and 2800 cm-1) and presence of the CO bond (1076 cm-1) indicating oxidation. Therefore, it was possible to conclude that the addition of pine bark and Radha modofied medium favors the biotransformation of oxo-biodegradable Oxo pretreated with O2 plasma by the ligninolytic white rot fungus P. ostreatus. Finally, for the third specific objective, the biotransformation of oxo-biodegradable LDPE Oxo was determined in a microcosm system that incorporated a filling mixture composed of pine bark, spent yeast and paper towels in a 3: 3: 1 ratio. For this, total carbon content (TOC), CO2 production, ligninolytic activity, as well as changes in the hydrophobicity, functional groups and colonization of oxo-biodegradable LDPE Oxo were evaluated. This showed a 41.38 % decrease in the organic carbon content, CO2 production of 2323.11 mg/kg and laccase (5266 U/kg), lignin peroxidase (169437 U/kg) and manganese peroxidase activity (5535 U/kg) to 75 days. On the other hand, in terms of Oxo-biodegradable LDPE biotransformation Oxo, a decrease of 83.32 % in hydrophobicity was registered as well as colonization of the polymer by the presence of hyphae and mycelium on SEM analysis. Also changes in the functional groups CH3 and CH2 (2900 cm -1 and 2800 cm-1) and presence of polar groups resulting from the oxidation of hydroxyl-OH polyethylene (3400-3200 cm-1) and associated with the presence of the CO bond (1076 cm-1) were observed. These results highlighted the possibility of a co-treatment of lignocellulosic material and oxo-biodegradable LDPE using P. ostreatus.