M9 salts

Next, 100-μL portions of Fusarium sp. DS 682 spore suspension were added to M9 PDA plates, followed by incubation at 28°C for 2 weeks. M9 PDA medium was prepared by adding micronutrients (see recipe below), 24 g/L potato dextrose (BD Biosciences, San Jose, CA), and 2% granulated agar (BD Biosciences) to M9 salts (MP Biomedicals, Irvine, CA) in Millipore water. The micronutrients consisted of 0.145 mM ammonium molybdate (Thermo Fisher Scientific), 2 mM boric acid (Sigma-Aldrich, St. Louis, MO), 0.151 mM cobalt chloride (Sigma-Aldrich), 0.048 mM cupric sulfate (Sigma-Aldrich), 0.404 mM manganese chloride (Sigma-Aldrich), and 0.048 mM zinc sulfate (Thermo Fisher Scientific). These micronutrients were added after autoclaving the M9 PDA solution, when the solution was ~55°C. After pouring the M9 PDA into petri dishes, the solidified agar plates were wrapped in Parafilm and stored at 4°C for future use. M9 PDA plates were primarily used to maintain the fungal cultures and not in the micromodel experiments described in this paper. The fungal experiments in the micromodel and for proteomics analysis were conducted using PDA plugs and PDA plates, respectively, as described in detail below.

Sixteen pieces of EPS plastic waste were cut in half (to approximately 1–2 cm diameter), with one half placed in a 3 mL LB culture and grown overnight with agitation at room temperature, collected for glycerol stock and spotted onto PCL agar plates to assess PCL degradation activity through a zone clearing assay, as described in the following section. The other half was placed into 3 mL high salt M9 minimal media with no carbon source (1× M9 salts (MP Biomedicals), NaCl concentration increased to 35 g/L (the same concentration as sea water), 2 mM MgSO₄, 0.1 mM CaCl₂ in autoclaved distilled water, solution filter‐sterilized) and grown for 53 days with agitation at room temperature. After 53 days, the culture was inoculated into 3 mL LB, grown overnight for glycerol stock, and spotted onto PCL agar plates to assess PCL degradation activity through a zone clearing assay.