College of Natural and Computational Sciences

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    PHYSICAL PROPERTIES AND CHEMICAL COMPOSITIONS OF PASTEURIZED COW MILK MARKETED IN ADDIS ABABA, ETHIOPIA
    (Hawassa University, 2024-11) WUBEDEL TEKA
    Milk represents an important intake in a typical diet due its high nutrient and mineral content. Consequently, milk must be of satisfactory quality in order to protect the health of the community. This study investigated Physical Properties and Chemical Compositions of Pasteurized Cow Milk Marketed in Addis Ababa, Ethiopian. Seven locally available pasteurized cow’s milk samples were collected and codes were given. Physical Properties and Chemical Compositions were determined following standard methods of analysis. The mean values of pH, moisture, total solids, total ash and titratable acidity were in the range of 5.81–6.42, 84.78 91.91%, 8.09–15.16%, 0.546–0.739%, and 0.228–0.411%, respectively for the seven pasteurized milk samples. The determination of minerals in pasteurized cow’s milk samples were carried out after optimization of the digestion of milk, which were found to be (5.0 mL HNO3 (70%): 3.0 mL HClO4 (70%) volume ratio of reagents, 200 °C digestion temperature and 2:00 hours digestion time for the digestion of 5.0 mL of milk samples. The mean concentration of Ca, Mg, Cu, Mn, Ni, Co and Cr were in the range of 1041.00–1609.00 mg/L, 72.00–122.00 mg/L, 0.0351–0.0819 mg/L, 0.0511–0.1019 mg/L, 0.0601–0.0684 mg/L, 0.0518–0.0814 mg/L and 0.0531–0.0809 mg/L, respectively for the seven pasteurized cow’s milk samples. In this study, the concentration of Ni was also found to be below the detection limits for pasteurized cow’s milk samples such as AA/B1, AA/B4, and AA/B6. However, the concentration of Pb was found to be below the detection limits for all pasteurized cow’s milk samples. Results indicated that there were significant differences (P<0.05) in most of the evaluated physicochemical parameters and minerals content among the seven pasteurized milk samples. The accuracy of the method for the determination of the selected elements was evaluated through recovery experiment and it lied within the range 98.0% to 114.1%, which is in the acceptable range (80–120 %). Generally, the levels of the selected physicochemical parameters and several metals were mostly found above the safe limits adopted from international food standards like WHO/FAO.
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    1,4-BENZOQUINONE MODIFIED CARBON PASTE ELECTRODE FOR VOLTAMMETRIC INVESTIGATIONOF DOPAMINE
    (Hawassa University, 2025-04) KASSA BEKO
    Dopamine (DA) is one of electrochemically active molecule; electrochemical techniques currently have received great interest for their investigation due to their simplicity, cost effective, low detection limit, and fast response time. This study investigates the electrochemical oxidation of dopamine using a low-cost and sensitive voltammetric method based on a 1,4-Benzoquinone modified carbon paste electrode. Cyclic voltammetry revealed significant enhancements in the oxidative peak current for dopamine at the modified electrode compared to unmodified carbon paste electrode, indicating its electrocatalytic properties. Scan rate, pH, differential pulse amplitude, and concentration of dopamine were optimized for the investigation of dopamine. The optimized values were 100 mV/s, 7, and 240mV, respectively. The voltammogram resulted from those parameters showed that quasireversible nature of the analyte towards modified electrode with the transfer of two electrons per molecule of the analyte. The dependence of anodic peak current on the square root of scan rate with high correlation coefficients (R2=0.99907 and scan rate (R2=0.99103) indicated that, the diffusion control is dominant, but adsorption also plays a role. Key kinetic parameters were calculated: anodic transfer coefficient (α =0.798), diffusion coefficient (D=2.18×10−7 cm2/s), and heterogeneous electron transfer rate constant (Ks,h=2.26×10−4 cm/s). Anodic transfer coefficient (α =0.798) value is closer to one this suggests that anodic process is more favorable. Optimization of experimental conditions led to be a linear response for DA concentration ranging from 1.0 × 10−3 M to 3.5 × 10−3 M, with a detection limit of 1.39 × 10−4 M using cyclic voltammetry and 7.64 × 10−5 M with differential pulse voltammetry. The result suggests that 1,4-BQMCPE is a promising electrode material for the development of electrochemical sensors for DA detection.
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    PHOTOCATALYTIC DEGRADATION OF CRYSTAL VIOLET UNDER SOLAR IRRADIATION USING A BIOSYNTHESIZED ZnO BASED POLYANILINE
    (Hawassa University, 2024-06) BELAYNESH SIRIYE TALILA
    A morphologically modified PANI/ZnO Nanocomposite was synthesized using leaf extract from Solanecio gigas (S. gigas) a reducing and capping agent for the photocatalytic degradation of Crystal Violet (CV) under natural sunlight irradiation. Additionally, PANI and pure ZnO NPs were synthesized via a green route, and the nanomaterials were characterized using spectroscopic techniques such as UV-Vis, FT-IR, SEM, and XRD. The blue-shift in the absorption peak of PANI/ZnO NCs suggests a change in electronic structure, potentially due to a type-II heterojunction between PANI and ZnO. FTIR analysis revealed red-shifted peaks, indicating hydrogen bonding between ZnO and PANI. Morphologically, the composite material combines the roughness of ZnO NPs with the smoothness of PANI. XRD patterns showed overlapping peaks from the composite with a crystalline size of 5.577 nm, which is smaller than the crystalline size of ZnO NPs (9.455 nm). This reduction in size is likely due to the formation of a polymer-Zn complex on the nanoparticle surface. The photocatalytic activity of the polyaniline/ZnO nanocomposite in degrading CV in aqueous solution under natural sunlight irradiation was evaluated and compared with that of ZnO nanoparticles. The effects of experimental conditions such as pH, photocatalyst dosage, and CV concentration were investigated with 91.20% and 99.06% at pH 11, 99.47% and 99.97% at 0.12 g, and 94.93% and 96.20% at 20 ppm for both ZnO NPs and PANI/ZnO NCs. The ZnO/polyaniline nanocomposite exhibited higher photocatalytic activity at 98.25% compared to ZnO nanoparticles at 92.76% under optimal conditions after 60 minutes of sunlight exposure. Kinetics studies indicated that the degradation rate fit well with the pseudo-first-order kinetics model, showing an R2 value of 0.968 for PANI/ZnO NCs. The composite demonstrated good catalytic activity with four cycles of reusability time compared to non-coated ZnO NPs. These findings highlight the potential of S. gigas plant-assisted PANI/ZnO NCs as effective and sustainable nanocatalysts with promising applications in catalytic decomposition of organic contaminants for environmental remediation.
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    DESIGN AND SYNTHESIS OF SOME NOVEL HYBRID MOLECULES CONTAINING INDOLE AND OXADIAZOLE RING FOR EVALUATION OF ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES
    (Hawassa University, 2024-06) AMANUEL ABRIHAM BUDE
    Indole-containing oxadiazole compounds have emerged as a versatile class of nitrogen containing heterocyclic compounds with a wide range of biological activities. These compounds and their derivatives exhibit a diverse array of properties such as antiviral, anticancer, anti-HIV, antioxidant, antimicrobial, antidiabetic, and antimalarial activities. The aim of the study was to design and synthesize some novel hybrid molecules containing an indole and oxadiazole rings, followed by partial characterization of the synthesized compounds using UV-vis and FT-IR spectroscopic techniques, and assessment of their antibacterial and antioxidant activities. The synthetic methodology was initiated by esterification of 2-(1H-indol-3-yl) acetic acid (105aʹ) and 4-(1H-indol-3-yl) butanoic acid (105bʹ) using a catalytic amount of sulfuric acid and excess methanol. This process resulted in the formation of methyl 2-(1H-indol-3-yl)acetate (106aʹ) and methyl 4-(1H-indole-3-yl)butanoate (106bʹ) respectively. These esters were further converted to 2-(1H-indol-3-yl)acetohydrazide (107aʹ) and 4-(1H-indole-3-yl)butaneydrazide (107bʹ) respectively. Finally, the compounds (107aʹ) and (107bʹ) underwent a reaction with substituted carboxylic acids in the presence of POCl3 to produce the desired targeted compounds: 110aʹ, 111aʹ, 110bʹ, and 111bʹ. The synthesized compound yields were as follows: 110aʹ (62%), 111aʹ (55%), 110bʹ (57%), and 111bʹ (53%). The chemical structures of these synthesized compounds were partially characterized by using spectroscopic techniques like UV-Vis and FT-IR. The synthesized compounds were evaluated for their in vitro antibacterial activity test against four bacterial strains: E. coli, P. aeruginosa, S. pyogenes and S. aureus by the disk diffusion method. Among synthesized compounds, compound 111bʹ showed potent inhibitory activity against Gram-negative, E. coli with 11.57 ± 0.15 mm zone of inhibition compared to the standard drug tetracycline (13 ± 0.5 mm) at 150 mg/mL. The RSA of synthesized compounds were assessed through DPPH radical assay, revealing that compounds 111aʹ and 110aʹ demonstrated higher %RSA (91.83% and 89.9%, respectively) with IC50 values of 4.95 and 5.03, respectively, compared to the standard ascorbic acid of %RSA (87.5%) with an IC50 of 31.44 and than other synthesized compounds. Hence, the studies have indicated that all the synthesized compounds could be considered as potential candidates for further investigation in antibacterial and antioxidant research.
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    A COMPARATIVE ANALYSIS OF PHYSICOCHEMICAL PARAMETERS AND MINERAL CONTENT IN COW AND CAMEL MILK FROM AGA WAYU DISTRICT, GUJI ZONE, OROMIA, ETHIOPIA
    (Hawassa University, 2024-06) DINAOL BAYU
    This study aims to analyze and compare the physicochemical properties and mineral composition of cow’s and camel’s milk. Milk samples were collected from the Aga Wayu district in the Guji zone of the Oromia region, Ethiopia, using a proportional random sampling method. The physicochemical parameters analyzed included pH, titratable acidity, ash content, specific gravity, protein content, fat content, moisture content, total solids, and boiling point. Additionally, the concentrations of selected minerals (phosphorus, sodium, calcium, and potassium) were measured. The results showed that cow’s and camel’s milk exhibited similar physicochemical properties, with comparable pH (5.8 ± 0.5), titrateble acidity (0.20 ± 0.01), ash content (0.84 ± 0.12%), specific gravity (1.04 ± 0.11), protein content (3.32 ± 0.43%)for cow, fat content (3.6 ± 0.48%) and boiling point (92.66°C)for camel. The concentrations of sodium (3.63 ± 1.23 mg/L) and phosphorus (2.43 ± 0.39 mg/L) were also similar in both types of milk. However, cow’s milk had higher moisture content (85.13 ± 2.65%) and calcium levels (22.44 ± 2.41 mg/L) compared to camel’s milk, which had lower moisture (82.83 ± 1.22%) and calcium (17.07 ± 1.38 mg/L). Conversely, camel’s milk contained higher total solids (18.26 ± 0.50%) than cow’s milk (14.82 ± 2.11%). In conclusion, camel’s milk was found to have higher protein and lactose content than cows’s milk, while cow’s milk had a greater fat content. These findings highlight the distinct nutritional profiles of the two types of milk, which may have implications for their dietary applications.
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    ASESSMENT OF PHYSICO-CHEMICAL AND BACTERIOLOGICAL QUALITY OF DRINKING WATER SUPPLY, STATUS OF SANITATION AND HYGIENE PRACTICES: THE CASE OF BISHAAN GURRACHA TOWN, WEST ARSI ZONE, OROMIA REGIONAL STATE, ETHIOPIA.
    (Hawassa University, 2024-05) MATIYAS AZAGE BETANE
    Access to safe drinking water and adequate sanitation is essential for safeguarding public health. This study aimed to assess the physicochemical and bacteriological quality of drinking water supply and evaluate sanitation and hygiene practices in Bishaan Gurracha town, located in the West Arsi zone of the Oromia region, Ethiopia. The methodology involved selecting water sources and households for sample collection, employing data collection instruments including household surveys, key informant interviews, focus group discussions, and direct observations. Laboratory analyses were conducted to measure various physicochemical parameters such as pH, turbidity, TDS, EC, alkalinity, nitrates, chlorides, free chlorine, heavy metals, and bacteriological indicators including total coliforms and fecal coliform. Sanitation coverage and hygiene practices were assessed using appropriate questionnaires to ensure data suitability for statistical analyses. The results indicated that most physicochemical water quality parameters met the standard values recommended by WHO/ESA, except for temperature and turbidity. Temperature ranged from 24.33°C to 26.17°C, and turbidity ranged from 5.62 NTU to 6.73 NTU. Total coliforms were present in all water samples from source water and household storage containers, with a significant number of samples also testing positive for fecal coliforms. The mean total coliform counts varied between 18 CFU/100ml to 101 CFU/100ml for source water and 16 CFU/100ml to 81 CFU/100ml for household storage water. These findings suggest potential deterioration in the untreated drinking water distribution system within Bishaan Guracha town, as the total coliform and fecal coliform counts exceeded the recommended standards set by national and WHO guidelines. Inadequate sanitation facilities in many homes pose significant health risks to the community in Bishaan Guracha town. The absence of proper toilets and improved sanitation systems increases the likelihood of fecal contamination, leading to the transmission of waterborne diseases such as diarrhea, cholera, and typhoid fever. Immediate interventions are therefore necessary, including decontamination of water sources, repair of distribution lines, expansion of sanitation infrastructure, and increased awareness of hygiene practices. It is recommended to regularly monitor water quality and encourage community participation in sustainable water, sanitation, and hygiene services.
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    ASSESSMENTS OF HOSPITAL SOLID WASTE MANAGEMENT: THE CASE OF SAINT PAULS MILLENNIUM MEDICAL COLLEGE’S HOSPITAL AND GIRUM HOSPITAL, ADDIS ABABA, ETHIOPIA
    (Hawassa University, 2024-05) FEKEDE GELETA HORA
    With an emphasis on the potential threats hospital solid waste poses to healthcare personnel, the public, and the environment if improperly managed, the study assessed the solid waste management practices at St. Paul's Millennium Medical College and Girum Hospital in Addis Ababa, Ethiopia. The study's objectives were to characterize the types, determine the generation rates, assess the KAP of the hospitals administrative and health care workers, and investigate the challenges and opportunities in hospital solid waste management’s of the study Hospitals. A cross-sectional study was undertaken to assess HCW management methods and generation rate using direct observation, interviews, questionnaire surveys, and weighing scales, with data analyzed using SPSS 22. The Government Hospital (St. Pauli's) generated 882.30±49.54 kg/day of total solid waste, with an average of 1.757 kg/patient/day (1.6 kg bed day‒1 and 0.157 kg/outpatient/day) of 61.25% being classified as hazardous waste, and the remaining 38.75% being general waste. The private hospital (Girum) produced 124.81±65.24 kg/day of total solid waste, with an average of 2.12 kg/patient/day (1.8 kg bed‒1day-1 and 0.32 kg/outpatient/day) of 57.05% being classified as hazardous waste, while the remainder, 42.795%, was general waste. High hazardous waste generation rates exceed the WHO's 10–25% estimate, primarily due to inadequate waste source segregation. The Kruskal-Wallis test showed significant differences in waste generation rates between hospitals for all the HCW categories (P < 0.05). However, no significant difference was found in the mean generation rate of the HCW within the government hospital wards as well as within the private hospital wards (P˃ 0.05). Ward chiefs, medical directors, and department heads all have high KAP scores; however, "hospital administrators have a medium, and waste handlers have a low." The KAP scores of the private hospital outperformed that of the government. St. Paul's intermediate storage area converts all forms of waste (excluding sharp waste) into hazardous waste. St. Paul's inadequate placenta disposal, as well as Girum Hospital's feeding all types of produced trash into a low-combustion incinerator, may have endangered both the population and the environment. Inefficient waste management is caused by a lack of legislation and failure to follow guidelines.
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    THE SYNERGISTIC ROLE OF ARBUSCULAR MYCORRHIZAL FUNGI, RHIZOBIUM INOCULATION, AND IN-FIELD RAINWATER HARVESTING TECHNIQUES IN GROWTH AND YIELD IMPROVEMENT OF MAIZE IN YIRBA DUWANCHO DISTRICT, SIDAMA REGIONAL STATE, ETHIOPIA.
    (Hawassa University, 2024-04) DINKNESH DIKALE
    Various climatic factors, such as temperature and rainfall variability, have a significant impact on rain fed agricultural productivity, especially in Ethiopia's water-stressed arid and semi-arid regions. The objective of this study was to assess the possible impact of arbuscular mycorrhizal fungus (AMF),Rhizobium® inoculation and in-field rain water harvesting system on maize (Zea mays) growth and production in a moisture-prone (low rainfall) location of Yirba duwancho village of Boricha woreda in Ethiopia. The experiment was laid out in a randomized complete block design (RBCD), with 8 treatments and 3 replication including the control. Consortia AMF inoculums and Rhizobia were used as bio-inoculants and a blended fertilizer in the form of NPSB was used as additional agricultural input. The highest height (140.6cm) growth was recorded for the maize-haricot bean intercropping treatment. This was followed by AMF+F (113.5cm) treatment. Stem collar diameter was bigger (1327mm) in maize-haricot bean intercropping followed by AMF+R (86.9mm). Records for Leaf area index, Shoot weight weight, Shoot dry weight, Root weight weight, and Root dry weight were inconsistent. The better (1853cm2) Leaf area index was recorded for R treatment. Shoot dry weight was better in AMF+R (830.6g) treatment. However, Root dry weight was higher (69.6g) in AMF+R+F treatment. Maize yield/plot and per hectare was higher for intercropping treatments followed by AMF+F and AMF+R respectively. For all control treatment was recorded the lowest values. Treatments on the Effect of the Suitability of In-field Rainwater Harvesting Technique with Respect to the Width of its Runoff Strips showed Application of Tide-Ride is the best technique to hold water in soil followed by IRWHI. The lower values were recorded for IRWH1.5 and the conventional broadcast treatment. This tells us the broader the width of runoff the least rain water retained in soil. Besides, better root colonization and spore density was recorded for intercropping followed by Sole AMF treatment, while mycorrhizal dependency and maize tissue nutrient uptake was much better in AMF+R treatment. However, in almost all cases the control treatment was inferior. Overall, results of this study suggest that mycorrhizal and rhizobium inoculation and application of infield rain water harvesting techniques enhances nutrient uptake and maximizes maize biomass under low soil moisture conditions. Mycorrhizal plants produced higher biomass, with greater tissue nutrient content than the control plants. These results indicate that establishing efficacious AMF and rhizobium with maize could be an efficient alternative for growers in drought prone areas than relying on fertilizer application and its associated costs and environmental concerns.
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    IMPACT OF LAND USE TYPE ON THE DIVERSTY AND ABUNDANCE OF ARBUSCULAR MYCORRHIZAL FUNGI IN LOKA ABYA, SIDAMA REGIONAL STATE, ETHIOPIA
    (Hawassa University, 2024-04) DILGASA TUSHURA
    Arbuscular mycorrhizal fungi play a crucial role in plant health by enhancing nutrient uptake, improving soil structure, and supporting ecosystem stability.This study investigates the role of AMF in the soil-plant interactions across different land-use types in Loka Abaya Woreda, Sidama Region, Ethiopia.The study examines the influence of soil physicochemical properties and plant species diversity on AMF distribution, spore density, and root colonization in agroforestry, natural forests, and cash crop systems.Soil characteristics, including pH, nitrogen, phosphorus, organic carbon, electrical conductivity, and texture, were analyzed across four land-use systems: agroforest, natural forest, cash crop, and grassland, revealing significant variation among different plant species. The soils were slightly acidic to neutral, with pH values ranging from 5.73 to 7.56 and phosphorus concentrations varying from 0.0100 mg/g to 0.3120 mg/g. Plant diversity was assessed using random sampling, resulting in the collection of 414 soil samples. Root colonization rates varied significantly, with Citrus sinensis exhibiting the highest colonization in field soil (94.5%), while Ehretia cymosa Thonn and Euphorbia abyssinica showed lower rates. In natural forests, Lennea schimper had 100% colonization, while Dodonaea angustifolia L.f. exhibited the lowest (84%). AMF colonization and spore densities were generally higher in trap cultures compared to field soils, with the highest spore densities in Psidium guajava (2251 spores/100 g) and Balanites aegyptiaca (1228 spores/100 g). Cash crops like Coffee arabica showed 100% AMF colonization and the highest spore density (838 spores/100 g in field soil). AMF analysis was conducted using Pearson's correlation, with data processed using SPSS software version 24.The study identified 30 AMF morphospecies from eight genera, with five genera Glomus, Acaulospora, Claroideoglomus, Enterophospora, and Rhizophagus intraradices showing significantly higher spore production, contributing 43.50%, 32.33%, 8.46%, 4.23%, and 3.62% of the total spore count, respectively. Notably, no single AMF species dominated across all land-use types, but four species Glomus sp.2, Claroideoglomus sp.1, Glomus mosseae, and Acaulospora sp.2 were commonly found, highlighting their ecological significance. The study found a positive correlation between spore density, root colonization, organic carbon, and nitrogen levels, while high phosphorus and soil pH negatively impacted AMF abundance. These findings emphasize the importance of agroforestry and natural forests in maintaining AMF diversity and enhancing soil health. The study recommends further research into AMF dynamics, particularly across different seasons and with molecular techniques, to enhance the understanding and application of AMF in agricultural systems.
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    Characterization, Symbiotic Effectiveness and Host range of Alfalfa Nodulating Rhizobia Isolated from Soils of Selected Kebele‘s in Hawella District, Sidama Regional State, Ethiopia.
    (Hawassa University, 2024-06) Bunamo Mitiku
    Feed shortage, low quality and seasonal fluctuations have constrained livestock production in Ethiopia. Using high-yielding, good quality and drought-tolerant forage legumes like alfalfa (Medicago sativa L.) has been suggested to overcome the feed constraints. Alfalfa is an important forage crop, which forms a symbiotic relationship with nodule-forming bacteria Sinorhizobum meliloti. The aim of this study was to characterize and evaluate the symbiotic effectiveness and host range of rhizobia isolated from smallholder farmers’ fields in Hawella District, Sidama Regional State of Ethiopia using Alfalfa as a trap plant. To this end, a total of 12 bacterial isolates were trapped from different soil samples. The isolates showed differences in various presumptive, cultural, biochemical characteristics and physiological tolerances. Six (50 %) of the isolates( ANR 9, ANR 8, ANR 2, ANR 1, ANR 5 and ANR 11) could nodulate alfalfa with significant difference (P<0.05) in their capacity to infect and effectively fix nitrogen as evidenced from variations in nodulation parameters, shoot dry weights and shoot length. Accordingly, the isolates induced nodulation with nodule number ranging from 25.67 (ANR 9) to 9.00 (ANR 11) nodule per plant; nodule dry weight of 0.07 mg per plant (ANR 9) to 0.03 mg per plant (ANR 11); shoot dry weight ranging between 0.96 (ANR 9) and 0.17 (ANR 4) mg per plant and shoot length ranging from 30.50 (ANR 9) cm -11.47 (ANR 4) cm per plant. Using shoot dry weight as an indicator of the relative effectiveness, it was found that 33.3% of the isolates were highly effective (SE > 85 %) and 8.3 % were effective (SE ranging from 55 to 85 %) on alfalfa. Furthermore, the isolates showed broad host ranges on three legume species, namely, faba bean (Vicia faba), common bean (Phaseolus vulgaris), and lentil (Lens culinaris). All the six isolates (100 %) formed nodules with effective nitrogen fixation in faba bean, common bean and lentils exhibiting varying levels of effectiveness. Five of the six rhizobial isolates, ANR 9, ANR 8, ANR 2, ANR 1 and ANR 5 exhibited high N2-fixation efficiency and are recommended for further evaluation to use them as inoculants for different legumes. We also recommend these isolates for molecular characterization to determine their phylogeny and taxonomic classes.