Diriba Muleta

Dr. Diriba Muleta

orcid

Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 August 2019 in International Journal of Microbiology
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Journal Article
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GMGuesh Mulaw
Guesh Mulaw
TTTesfaye Sisay Tessema
Tesfaye Sisay Tessema
DMDiriba Muleta
Diriba Muleta
ATAnteneh Tesfaye
Anteneh Tesfaye
Probiotics are live microorganisms which when consumed in large number together with a food promote the health of the consumer. The aim of this study was to evaluate in vitro probiotic properties of lactic acid bacteria (LAB) isolated from traditional Ethiopian fermented Teff injera dough, Ergo, and Kocho products. A total of 90 LAB were isolated, of which 4 (4.44%) isolates showed 45.35–97.11% and 38.40–90.49% survival rates at pH values (2, 2.5, and 3) for 3 and 6 h, in that order. The four acid-tolerant isolates were found tolerant to 0.3% bile salt for 24 h with 91.37 to 97.22% rate of survival. The acid-and-bile salt-tolerant LAB isolates were found inhibiting some food-borne test pathogenic bacteria to varying degrees. All acid-and-bile-tolerant isolates displayed varying sensitivity to different antibiotics. The in vitro adherence to stainless steel plates of the 4 screened probiotic LAB isolates were ranged from 32.75 to 36.30% adhesion rate. The four efficient probiotic LAB isolates that belonged to Lactobacillus species were identified to the strain level using 16S rDNA gene sequence comparisons and, namely, were Lactobacillus plantarum strain CIP 103151, Lactobacillus paracasei subsp. tolerans strain NBRC 15906, Lactobacillus paracasei strain NBRC 15889, and Lactobacillus plantarum strain JCM 1149. The four Lactobacillus strains were found to be potentially useful to produce probiotic products.

5 September 2016 in International Journal of Microbiology
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Journal Article
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FEFirew Elias
Firew Elias
DWDelelegn Woyessa
Delelegn Woyessa
DMDiriba Muleta
Diriba Muleta
Phosphorus (P) is one of the major bioelements limiting agricultural production. Phosphate solubilizing fungi play a noteworthy role in increasing the bioavailability of soil phosphates for plants. The present study was aimed at isolating and characterizing phosphate solubilizing fungi from different rhizospheres using both solid and liquid Pikovskaya (PVK) medium. A total of 359 fungal isolates were obtained from 150 rhizosphere soil samples of haricot bean, faba bean, cabbage, tomato, and sugarcane. Among the isolates, 167 (46.52%) solubilized inorganic phosphate. The isolated phosphate solubilizing fungi belonged to genera ofAspergillus(55.69%),Penicilliumspp. (23.35%), andFusarium(9.58%). Solubilization index (SI) ranged from 1.10 to 3.05. Isolates designated as JUHbF95 (Aspergillussp.) and JUFbF59 (Penicilliumsp.) solubilized maximum amount of P 728.77 μg·mL−1and 514.44 μg mL−1, respectively, from TCP (tricalcium phosphate) after 15 days of incubation. The highest (363 μg mL−1) soluble-P was released from RP with the inoculation of JUHbF95 in the PVK broth after 10 days of incubation. The present study indicated the presence of diverse plant associated P-solubilizing fungi that may serve as potential biofertilizers.

1 August 2019 in Journal of Food Quality
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KZKibrom Zerabruk
Kibrom Zerabruk
NRNegussie Retta
Negussie Retta
DMDiriba Muleta
Diriba Muleta
ATAnteneh Tefera
Anteneh Tefera
Food-borne pathogens are one of the leading causes of illness and death particularly in developing countries. This study was aimed at analyzing the hygiene indicator microorganisms and pathogens of minced meat and contact surface materials in butcher shops in Addis Ababa, Ethiopia. Additionally, a checklist was applied to evaluate the hygiene condition of the establishments, and a questionnaire/checklist was used to assess food safety knowledge of the food handlers. This study has indicated that the mean microbial counts (total aerobic mesophilic, staphylococci,Enterobacteriaceae, total coliforms, fecal coliforms, aerobic spores and yeasts/molds) of the minced meat and contact surface materials in butcher shops ranged between 2.35 and 6.50 log·cfu/g and between 1.80 and 6.30 log·cfu/cm2, respectively. The mean microbial counts of minced meat samples taken in the morning and afternoon showed statistically significant differences (p<0.05). The prevalence ofE. coli,Salmonella, andS. aureusin minced meat and contact surface samples was exhibited as 43.75 and 29.17%, 6.25 and 4.17%, and 37.50 and 37.50% in that order. The study has indicated that minced meat samples and contact surface materials had higher microbial load with poor personal and work area sanitation. Low knowledge of food handlers in the butcher shops and broken cold chain have also been found as major contributing factors for the contamination of beef.

11 February 2018 in Biotechnology Research International
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TFTemesgen Fufa
Temesgen Fufa
DMDiriba Muleta
Diriba Muleta
MMMulissa Jida Midekssa
Mulissa Jida Midekssa
Biological wastewater treatment is economically feasible and ecofriendly. This study was aimed at isolating bacteria from brewery wastes and evaluating their bioremediation potential as individual isolate and/or their consortium in reducing the pollutants of brewery effluents. A total of 40 bacterial isolates were recovered and of these the three best isolates were selected. The selected bacteria were identified to genus level by using morphological and biochemical characteristics. Accordingly, the isolates were identified as Aeromonas sp., Pseudomonas sp., and Bacillus sp. After 12 days of incubation, the removal efficiency of these three isolates and their combinations for biological oxygen demand and chemical oxygen demand varied from 73.55% to 94.85% and 76.78% to 93.25%, respectively. Total nitrogen and phosphorus removal was within the range of 54.43% to 77.21% and 41.80% to 78.18%, respectively. Total suspended solid, total solid, and total dissolved solids removal ranged from 66.74% to 90.3%, 54.69% to 88.5%, and 53.02% to 88.2%, respectively. The pH and electrical conductivity values ranged from 6.81 to 8.65 and 3.31 mS/cm to 3.67 mS/cm, respectively. The treated effluent increased Beta vulgaris seeds germination from 80% to 100%, with mean germination time of 3.1 to 5.2 days and seedlings length of 2.3 cm to 6.3 cm. Therefore, the development of this finding into a large scale offers an attractive technology for brewery waste treatment.

5 August 2018 in International Journal of Food Science
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BTBelay Tilahun
Belay Tilahun
ATAnteneh Tefera
Anteneh Tefera
DMDiriba Muleta
Diriba Muleta
ABAndualem Bahiru
Andualem Bahiru
ZTZewdu Terefework
Zewdu Terefework
GWGary Wessel
Gary Wessel
Injera is soft fermented baked product, which is commonly prepared from teff (Eragrostis tef(Zucc.)) flour and believed to be consumed on daily basis by two-thirds of Ethiopians.As it is a product of naturally fermented dough, the course of fermentation is done by consortia of microorganisms. The study was aimed at isolating and identifying some dominant bacteria from fermentingteff (Eragrostis tef)dough. A total of 97 dough samples were collected from households, microenterprises, and hotels with different fermentation stage from Addis Ababa. The bacterial isolates obtained from the fermentingteffdough samples were selected on the basis of their acid production potentials. A total of 24 purified bacterial isolates were found to be Gram-positive (they are coccus and rod under microscope) and were good acid producers. Genomic DNA of bacterial isolates were extracted using Invisorb® Spin DNA Extraction kit. 16S rRNA of bacterial isolates were amplified using the bacteria universal primers (rD1 and fD1). The amplified product was sequenced at Genewiz, USA. Sequence analysis and comparison with the resources at the database were conducted to identify the isolated microbes into species and strain levels. The bacterial isolates were identified asLactobacillus paracasei, Lactobacillus brevis, Enterococcus durans, Enterococcus hirae, Enterococcus avium,andEnterococcus faecium. All identified lactic acid bacteria were able to produce acid at 12 h time of incubation. This study has confirmed the presence of different bacterial species in the fermentingteffdough and also supports the involvement of various groups of bacterial species in the course of the fermentation.

29 October 2020 in International Journal of Microbiology
Verified
Journal Article
Open access
AGAlemayehu Getahun
Alemayehu Getahun
DMDiriba Muleta
Diriba Muleta
FAFassil Assefa
Fassil Assefa
SKSolomon Kiros
Solomon Kiros
Plant Growth-Promoting Rhizobacteria Isolated from Degraded Habitat Enhance Drought Tolerance of Acacia (Acacia abyssinica Hochst. ex Benth.) Seedlings: Drought stress (DS) is the most impacting global phenomenon affecting the ecological balance of a particular habitat. The search for potential plant growth-promoting rhizobacteria (PGPR) capable of enhancing plant tolerance to drought stress is needed. Thus, this study was initiated to evaluate the effect of inoculating Acacia abyssinica seedlings with PGPR isolated from rhizosphere soil of Ethiopia to enhance DS tolerance. The strains were selected based on in vitro assays associated with tolerance to drought and other beneficial traits such as salinity, acidity, temperature, heavy metal tolerances, biofilm formation, and exopolysaccharide (EPS) production. The strains with the best DS tolerance ability were selected for the greenhouse trials with acacia plants. The results indicate that out of 73 strains, 10 (14%) were completely tolerant to 40% polyethylene glycol. Moreover, 37% of the strains were strong biofilm producers, while 66 (90.41%) were EPS producers with a better production in the medium containing sucrose at 28 ± 2°C and pH 7 ± 0.2. Strains PS-16 and RS-79 showed tolerance to 11% NaCl. All the strains were able to grow in wider ranges of pH (4–10) and temperature (15–45°C) and had high tolerance to heavy metals. The inoculated bacterial strains significantly ( ) increased root and shoot length and dry biomass of acacia plants. One of the strains identified as P. fluorescens strain FB-49 was outstanding in enhancing DS tolerance compared to the single inoculants and comparable to consortia. Stress-tolerant PGPR could be used to enhance acacia DS tolerance after testing other phytobeneficial traits.