Mekelle Institute of Technology
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Item Therapeutic Potential of Impatiens tinctoria Tuber Extract and Its Green Synthesized Silver Nanoparticles against Trichophyton mentagrophytes(Mekelle University, 2025-05-21) Meron MengistuDermatophyte infections and antifungal resistance pose a global health challenge, particularly in developing countries, where existing treatments often fail and cause recurrence and side effects. This study evaluated the antioxidant and antifungal properties of Impatiens tinctoria tuber extract and its green-synthesized silver nanoparticles (AgNPs) against Trichophyton mentagrophytes. Tuber extracts were obtained using aqueous, ethanolic, and methanolic solvents, and their phytochemical constituents were analyzed. AgNPs were synthesized using an aqueous extract under optimized conditions (pH 9, 0.1:1 extract-to-AgNO₃ ratio, 5 mM AgNO₃, 45-minute reaction time, and 60°C), with maximum UV-Vis absorbance at 419 nm and an SPR peak at 425 nm confirming formation. AgNPs were characterized via UV–Vis, FTIR, XRD, and SEM, revealing a face-centered cubic crystalline structure with an average crystallite size of 9.28 nm and predominantly spherical morphology. Antioxidant activity was assessed using the DPPH radical scavenging assay, with ethanol extract showing the highest capacity (IC50 = 48.18 ± 1.40 µg/mL), followed by methanol (125.66 ± 1.45 µg/mL) and aqueous (163.70 ± 1.02 µg/mL) extracts. Biosynthesized AgNPs exhibited dose-dependent activity (IC50 = 148.56 ± 0.74 µg/mL), surpassing the aqueous extract but remaining lower than ethanol and methanol extracts. Ethanol extract showed the strongest in vitro antidermatophytic activity against T. mentagrophytes, surpassing terbinafine (inhibition zone: 36.3 ± 1.15 mm at 100 mg/mL). Methanol extract exhibited significant inhibition, while aqueous extract had the lowest effect. AgNPs demonstrated antifungal efficacy, increasing with concentration but remaining less potent than terbinafine. A formulation combining ethanol extract and AgNPs (Formulation 2) significantly enhanced antidermatophytic activity in vitro, while in vivo studies on mice showed faster recovery and complete healing, outperforming individual treatments and proving comparable to terbinafine. Acute oral and dermal toxicity studies confirmed that the ethanol extract, AgNPs, and their formulation were non-toxic at 2000 mg/kg, with no observed toxicity or mortality. These findings suggest that I. tinctoria tuber extract and its green-synthesized AgNPs hold promising potential as alternative therapeutic agents for dermatophytosis treatmentItem Screening and Identification of Potential Dye-Degrading Bacteria from Maa Garment Effluen(Mekelle University, 2025-06-21) Berihu ZenawiThe textile industry is a major contributor to water pollution, releasing effluents containing 10% - 15% unused dyes. These, dyes are resistant to biodegradation because their complex aromatic structures pose significant threats to aquatic ecosystems and human health. This study aimed to isolate, screen, and identify potential dye-degrading bacteria from the effluents of the Maa Garment and Textile Factory. Physicochemical parameters, including pH, temperature, total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand (BOD), and chemical oxygen demand (COD), were analyzed. Bacterial isolates were cultivated in dyecontaining media, and their decolorization efficiency was evaluated using spectrophotometry under varying conditions: temperatures (25°C, 30°C, 37°C, and 40°C), pH levels (5, 7, and 9), and dye concentrations (50, 100, and 150 mg/L). The collected samples exhibited pH levels ranging from 7.2 to 7.5 and the temperature varied significantly, with one sample reaching 38°C. A total of 16 bacterial isolates were screened for their decolorization capabilities under varying conditions of temperature, pH, and dye concentration. The results indicated that optimal decolorization occurred at 37°C and pH 7, particularly at a dye concentration of 50 mg/L. Under these conditions, the Pseudomonas aeruginosae isolates H5P, C2P, and C4P achieved 90% decolorization of reactive dyes. There were statistically significant differences (p < 0.001) among all environmental factors tested. These findings suggest that the isolated bacterial strains have considerable potential for the bioremediation of textile wastewater. This biological approach represents an environmentally sustainable and cost-effective alternative to conventional treatment methods. Further field trials and studies involving a broader range of dyes are recommended to validate their application in real-world wastewater treatment systemsItem Isolation and Characterization of Engine Oil-Degrading Bacteria from Contaminated Soil at Garage Centers in Mekelle(Mekelle University, 2025-06-20) Yohannes Tsegay TeklayThe release of engine oil by Mekelle mechanical workshops causes significant environmental pollution; bioremediation is an effective cleanup strategy. This study investigates the isolation and characterization of engine oil-degrading bacteria from contaminated soil at garage centers in Mekelle. Soil and water samples from ten garage centers in Mekelle were collected and analyzed for physicochemical properties. Bacteria were isolated using serial dilution and identified by morphological and biochemical characteristics. To assess the oil degradation ability, bacterial isolates were cultured on Bushnell-Haas agar with engine oil and incubated at 37°C for 14 days. Moreover, the isolates were evaluated for biosurfactant production, heavy metals and salt tolerance, antibiotic susceptibility, as well as for compatibility. Results showed the pH level of the soil ranging from 4.7 ± 0.2 to 6.6 ± 0.2, with temperatures between 25 ± 3.27°C and 34 ± 0.0°C. The isolates were identified as Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus aureus, Acinetobacter baumannii, Bacillus pumilus, and Bacillus megaterium. B. pumilus (98.9 ± 91.6%) showed the highest oil degradation rate in soil followed by A. baumannii (98.7 ± 80%). Whereas, B. megaterium (96.9 ± 92.8%), B. cereus (96.7 ± 88.2%), and P. aeruginosa (96.5 ± 84.6%) showed the highest biodegradation rate in water. However, B. megaterium (98.9 ± 88.8%) achieved a high degradation rate in media. The highest biosurfactant was produced by P. aeruginosa, A. baumannii, and B. cereus. S. aureus and A. baumannii exhibit broad tolerance to all tested heavy metals. P. aeruginosa, B. megaterium, B. cereus, and B. pumilus exhibit significant salt tolerance. Moreover, the antibiotic sensitivity testing reveals that P. aeruginosa, A. baumannii, and B. megaterium are promising candidates for bioremediation due to their susceptibility to effective antibiotics, while strains like B. cereus, S. aureus, and B. pumilus exhibit intermediate as well as multidrug resistance, necessitating careful antibiotic selection. So, from the results obtained, bacterial isolates could be the most effective for the bioremediation of oil spills.Item Evaluation of Aframomum corrorima Seed Extracts and Their Green Synthesized Silver Nanoparticles for Their Antioxidant, Antibacterial, and Wound Healing Activities(Mekelle University, 2025-04-28) Rahel Sisay WeredeThe emergence and spread of multidrug-resistant bacteria pose a significant medical challenge today. This research aimed to evaluate the antioxidant, antibacterial, and wound-healing activities of Aframomum corrorima seed extracts and their green-synthesized silver nanoparticles (AgNPs). Seeds of A. corrorima, collected from Hawassa, were ground into powder, macerated with ethanol, methanol, and water, and extracted using the Soxhlet extraction method. The qualitative phytochemical profile of the A. corrorima seed extracts was evaluated. AgNPs were synthesized from the A. corrorima extracts, and their properties were analyzed using UV-Vis and FTIR spectroscopies, Scanning electron microscopy, and X-ray diffraction. The three extracts and the AgNPs were tested against E. coli, P. aeruginosa, and S. aureus. The wound-healing potential of the extracts, formulations, and the AgNPs was evaluated using a mice model. The antioxidant capacities of the seeds and AgNPs were also assessed. Phytochemical analysis revealed flavonoids, tannins, glycosides, phenols, saponins, and quinones, with no detectable proteins. The methanol extract showed the highest antioxidant activity (IC50 23.38 ± 0.86 mg/ml), but AgNPs exhibited significantly greater potency (IC50 4.41 ± 0.025 mg/ml). AgNPs characterization confirmed nanoscale synthesis. Antibacterial assays demonstrated that AgNPs, seed extracts, and their formulations effectively inhibited E. coli, S. aureus, and P. aeruginosa, surpassing controls. AgNPs were most effective against S. aureus, and synergistic combinations enhanced antibacterial activity. Toxicity tests confirmed the safety of extracts and AgNPs in mice. Wound-healing studies in mice showed that seed extract, AgNPs, and their formulation significantly accelerated wound contraction compared to controls and nitrofurazone. The formulation improved healing by 11% over standard ointment. AgNPs and extracts displayed wound-healing comparable to nitrofurazone. This research highlights the potential of A. corrorima seed extracts and AgNPs as safe and effective sources of antioxidants, antibacterial agents, and wound-healing therapeutics, offering alternatives for multidrug- resistant bacterial infections and wound management.Item Isolation and characterization of Lactic Acid Bacteria from raw cow milk and evaluation of their probiotic potential(Mekelle University, 2025-04-28) Goiteom Senay NiguseCow milk is a rich source of lactic acid bacteria (LAB), a group of gram-positive bacteria with diverse applications in dairy, food, feed, and health. Despite this, the probiotic potential of LAB from cow milk remains under-researched. Therefore, the current study aimed to isolate and characterize LAB from raw cow milk and evaluate their probiotic potential. This study involved the isolation of LAB, followed by characterization of their morphology, various biochemical tests, and physiological properties. The LABs were evaluated for their potency and safety as probiotics, and finally, their potential use as starter cultures in yogurt formation was examined. Twenty-three (23) pure bacterial isolates were obtained from seven cow milk samples. Morphologically, eight isolates were cocci (35%), six were rods or bacilli (26%), and nine were coccobacilli (39%). Among these, nine (9) gram-positive and catalase negative isolates were selected for further investigation. These isolates were citrate-negative, non-motile, and indole- negative. All were TSIA-positive, with seven being homo-fermentative and two (M5 and M9) hetero-fermentative. Isolates M1, M2, M3, M4, M5, M6, M7, and M9 demonstrated salt tolerance at 1%, 4%, and 6% NaCl concentrations. Isolates M3 and M4 exhibited acid tolerance, growing at pH levels of 2, 4, 6, and 6.5. Isolates M1, M2, M3, M5, M6, M7, and M9 showed resistance to temperatures ranging from 15°C to 45°C. Isolates M2, M3, M5, M6, M7, M8, and M9 displayed tolerance to 0.4% and 0.6% phenol concentrations. None of the nine LAB isolates exhibited hemolytic activity. However, they showed varying degrees of antibacterial activity and displayed both susceptibility and resistance to antibiotics. Six isolates (67%) performed well as starter cultures for yogurt (riguo) production. The LAB isolates were tentatively grouped under the genera Lactobacillus, Enterococcus, and Leuconostoc. Overall, the isolated LAB from cow milk represents a potential source of probiotics. These LABs could serve as starter cultures in the dairy and food industries and may be developed into commercially viable probiotic products. Further studies, including molecular identification and characterization, are necessary to determine their specific strains.Collection Collection