Page 212 - Demo

216 PROCEEDINGS OF INTERNATIONAL SCIENTIFIC CONFERENCE ON APPLIED BIOTECHNOLOGYsample as well as of non-fermented control sample were serially diluted with ratios from 0-100%. Each reaction consisted of 20 %u00b5L of the standard or experimental sample mixed with 180 %u00b5L of 0.1 mM DPPH in a 96-well plate. After 30 minutes of reaction in the dark, the sample was measured at OD570 nm using a spectrophotometer (Biotek, USA). The ability to neutralize free oxygen radicals (Scavenging Activities - SA) generated from DPPH of the test sample is calculated according to the following formula:In which: ODsp is the optical density of the experimental sample; ODblsp: is the optical density of the experimental blank sample; ODct: is the optical density of the control sample; ODblct: is the optical density of the control blank sample.Construct a logarithm graph between the concentration of the experimental sample and the percentage of DPPH radical scavenging to calculate IC50.2.5. Evaluation of antibacterial activityThe agar well diffusion method was used to evaluate the antibacterial activity of fermented MFP against E. coli ATCC 25922, MRSA 3640, and S. aureus KCTC 1916 strains. The bacterial strains were cultured on LB medium at 37oC for 4-6 hours when the OD600 reached 0.6-0.8. The tested bacterial samples were diluted to a concentration of about 106 CFU/mL and 100 %u00b5L of bacterial suspension was plated on LB agar. The positive control for E. coliwas chloramphenicol (20 %u00b5g/well), the positive control for MRSA and S. aureus was mupirocin (0.2 %u00b5g/well). After loading 100 %u00b5L of sample into the agar well, the plate was incubated at 37oC for 24 hours to determine the diameter of the inhibition zone.