Whatman grade 1 qualitative filtration paper

Analysis of the interference of coumarin derivative, 7-hydroxy-6-nitro-2H-1-benzopyran-2-one, on mycelia growth was performed by determining the dry mycelia weight of A. fumigatus (ATCC 46913) and A. flavus (ATCC 16013) [15 , 16 (link)]. Flasks containing MIC (16 μg/mL) and MIC × 2 (32 μg/mL) of coumarin derivative in RPMI-1640 medium were inoculated with suspension of the test A. fumigatus (ATCC 46913) and A. flavus (ATCC 16013) strains. In the corresponding control, the same amount of coumarin derivative was replaced by distilled water. The system was incubated at 28°C for 8 days. Flasks containing mycelia were filtered through Whatman Grade 1 Qualitative Filtration Paper (particle retention: 11 μm) and then washed with distilled water. The mycelia were dried at 60°C for 6 h and kept at 40°C overnight. The filter paper containing dry mycelia from two independent assays was weighed, and the mean values were obtained. Percentage growth inhibition based on the dry weight of each at time of analysis was calculated according to Sharma and Tripathi [15 ].

Raw wastewater was first filtered through Whatman grade 1 qualitative filtration paper to remove large particles and then through a 0.22-μm filter (Stericup-GP, 0.22-μm polyethersulfone; Merck) for the removal of the majority of microorganisms present in the sample.