Low-density polyethylene (LDPE) is a major cause of persistent and long-term environmental pollution, due to its resistance to degradation. The polyethylene can be degraded in various methods: chemical degradation, thermal degradation, photo degradation and biological degradation. The use of microorganisms in plastic biodegradation is based on their ability to produce extracellular enzymes, which cleaves polymers into low-molecular weight fragments. These fragments are used by microbes as a source of carbon and energy. For the screening of microorganisms capable of degrading polyethylene different mineral salt media (MSM) have been reported in the scientific literature (Bonhomme 2003; Koutny, 2006; Jamil, 2015; Nakei, 2019). Thus, the aim of our research was to select the optimal mineral medium for LDPE biodegradation by the strain Penicillium verrucosum CNM-FP-02. It was selected 5 mineral media, which differed in salt content and N/P ratio. Each medium had 2 experimental variants – with and without LDPE (60 μm). After 40 days of submerged cultivation, the following parameters were determined: catalase activity and pH of cultural media, quantity of accumulated biomass, mass and rate of LDPE degradation, optical microscopy. It was observed that catalase activity on all media, except MSM 4, was higher in the presence of LDPE. On MSM 4 the catalase test was negative in both experimental variants. The pH index in the presence of LDPE became less acidic by 0.1 units in all media except MSM 5, where the pH became more acidic by 0.2 units. It was established that addition of polyethylene to the growth media (4 of 5 tested) stimulated the fungal biomass accumulation by 19.3-93.1%. A significant increase was noted on MSM 2 (by 92.7%) and MSM 3 (by 93.1%). The addition of LDPE to MSM 3 had an opposed effect, decreased the fungal biomass accumulation by 29.3%. The degradation of LDPE films was determined gravimetrically, by weighing the films before and after incubation. On MSM 3, 4 and 5, the LDPE degradation made up 0.41-0.49%, on MSM 1 – 0.56%, and on MSM 2 – 0.92%. The study of LDPE films under an optical microscope revealed that after the contact with the fungal cells, both the immobilization of the microorganism and the damage on the polyethylene surface occurred. Thus, under the experimental conditions, the MSM 2 medium, where the N/P ratio was 1:1, proved to be optimal to stimulate the biodegradation of LDPE by the strain P. verrucosum CNMFP02.figuraImmobilization of fungal hyphae on the surface of polyethylenefiguraTraces of damage on the surface of polyethylene