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SECTION II. APPLIED BIOTECHNOLOGY IN THE PHARMACEUTICAL INDUSTRY... 299at pH 7, after which any increase in pH value was accompanied by a decrease in both growth and pigment production. The data in Figure 3c show the effect of incubation time and moisture content on the pigment production of the fungal strain.Regarding the incubation time, the maximum value of fungal pigment production increased by increasing the incubation time until 18 days after which both growth and pigment production decreased (Fig 3d). The maximum pigment yield observed after 18 days of incubation was 3.09 %u00b1 0.04 O.D/ml (Figure 3d). Figure 3b shows that by increasing the moisture content, red pigment production gradually increased to a maximum value at 65% moisture content (3.86 %u00b1 0.07), and maintained the pigment production at 75% then gradually decreased with increasing moisture content to 85%.3.5. Antibacterial activity of pigment extract of M. purpureus strain HG12The antimicrobial activity of the pigment extract from M. purpureus HG12 was evaluated against four microbial strains, and the results are summarized in Table 3. The pigment extract demonstrated inhibitory effects on all tested microorganisms, with the largest inhibition zone observed against E. coli (10.52 %u00b1 0.33 cm). Moderate inhibition was recorded for S. typhimurium(7.68 %u00b1 0.2 cm), S. aureus (6.89 %u00b1 0.33 cm), and B. subtilis (6.56 %u00b1 0.33 cm), suggesting that the extract possesses broad-spectrum antimicrobial properties.In comparison, the negative control (DMSO) exhibited no inhibitory effects on any of the tested strains, confirming the absence of inherent antimicrobial activity. The positive control, tetracycline at 30 %u03bcg/mL exhibited significantly larger inhibition zones, particularly against B. subtilis (25.0 %u00b1 0.17 cm) and S. aureus(22.0 %u00b1 0.18 cm), indicating its higher efficacy.