Isolation And Characterization Of Red Pigment Producing Fungi From Soils And Evaluation For Its Antimicrobial Activities

Abstract

Natural colors are becoming more popular since they have less of a negative impact on the environment and human health than chemically produced colorants. Due to the simplicity of handling microorganisms and the manufacturing process, microbial pigments have been prioritized over all other naturally occurring coloring sources. The main aim of this study was to isolate, characterize, and optimize conditions for red pigment producing fungal strains from rhizospher area, river bank, grass land, cultivated land and evaluation of antibacterial activities of the produced pigment on safety of microbial pigments/natural color. The collected soils samples were serially diluted from 10-1 to 10-4 and pour plated onto mycological media and incubated at 28°C. After 5 days of incubation, the fungal colonies were counted, and two intensely red-pigmented fungal colonies (S1I3 and S10I12) were selected for further characterization and experimental studies. The various parameters influencing of red pigments producing fungi were optimized. The most important factors are: - pH, incubation temperature, incubation period, carbon sources, nitrogen sources and salt concentration. All the quantitative data gathered was analyzed using SPSS for Windows version 25. According to the study's findings, only 2 of the 23 fungal isolates identified from soil samples of the rhizosphere and grass land were producing red pigmented; the rest were not producing red pigment. Dextrose promoted high OD from S1I3 and fructose S10I12 (3.100+0.22 and 3.100+0.32) respectively pigmentation, but dextrose showed high OD on S1I3 which was (3+0.22).In S1I3, peptone, tryptone and Sodium nitrate increased growth and pigmentation. While room temperature 3+0.11 high and 2.339+0.23 high OD respectively for S1I3 and S10I12 and 28°C were resulted in high OD (3+0.11 and 3+0.22 respectively) in S1I3. In S10I12 growth character in room temperature (250C) and 28oC was almost the same. While pH8 was limiting for S10I12 by (2.264+0.23) the others (PH4, PH5.5, PH6.5 and PH 7 promoted high OD. In S10I12, PH7 was ideal for growth and pigmentation. Salt concentration of 0.5% and 2% showed high OD by 3+0.45 and 3+0.22 respectively for S1I3. With regard to four pathogenic microorganisms, the extracted pigments demonstrated antibacterial activities against (Staphlocous aureus (S.aureus), Escherichia coli (E.coil), Pseudomonas aeruginosa (P.aeruginosa) and Staphlocous agalatiea (S.agalatiea). The highest inhibition zone for S1I3 pigment extracted with ethanol was found against S. aureus (26+0.02), followed by P. aeruginosa (18+0.12), and the lowest inhibition zone for S. agalatiea (15+0.22).Following S.aureus(23+0.23), S.aglatiea (14+0.22) showed no activity from S10I12,then microorganism were not resistant to bacterial activity, then not all fungal pigment producing from soil samples are not creating inhibition zones to against to human pathogenic bacterial activies .The findings of this study clearly demonstrated that pigment-producing fungi are abundant in the rhizosphere of trees, capable of producing a wide range of color compounds that can be employed in a wide range of industries.