Department of Biological Sciences

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Evaluating the effect of soil moisture content on root-knot nematodes in University of Embu
(University of Embu, 2018) Koi, Elizabeth Wali
The distribution and abundance of root-knot nematodes is largely affected by soil moisture content. A study was conducted to examine the effects of soil moisture content on RKN in crops fields in University of Embu. The galling severity in plants was assessed using a scale. Soil samples were collected around the infected roots for determination of soil moisture. Data on galling severity and soil moisture content was subjected to ANOVA. Means were separated using Turkey’s test. Relationship between galling and soil moisture was determined using Pearson’s coefficient. Spinach and tomatoes were the most highly affected crops by root-knot nematodes and had a galling severity of 8, which is equivalent to 66%-75% of roots galled. There was a significant difference (P <0.05) in galling severity between the crops. There was a significant correlation between soil moisture and galling severity.
Xtremophile Bacteria Utilizing Nitrile as Sole Carbon and Nitrogen Sources
(University of Embu, 2019) Akinyi, Meir Dayan
Nitriles are aliphatic and cyanide containing compounds R-CN. Nitriles are widespread in the environment as a result of biological and industrial activities. Naturally occurring nitriles are found in higher plants, bone oils, and insect. It been proven that microorganisms have the capacity to synthesize naturally occurring nitriles. Synthetic nitriles, have been used in the manufacture of herbicides such as 2,6-dichlorobenzonitrile and 3,5-dibromo-4hydroxybenzonitrile and the synthesis of polymers, plastics, and organic solvents. The hydrolysis of nitrile involves two stepwise pathways with enzymes like nitrilases, amidases and nitrile hydratase. Very little information is available on the ecological impact of organic nitriles and their derivatives. It is highly conceivable that the direct discharge of wastewater containing some of these nitrile compounds could cause severe health hazards, since most of them are highly toxic and some are mutagenic and carcinogenic. Only a few microorganisms are able to metabolize nitrile compounds and their derivatives. The aim of this research is to assess extremophiles bacteria utilizing nitrile as the sole carbon and nitrogen by enzymatic reaction and to achieve this aim there was different activities such as screening and exploring diversity of extremophile bacteria from soil of soda lakes of Rift Valley on media enriched with butyronitrile and isobutyronitrile and identification by morphology and biochemical test. The reason why soda lake soils are used is because; a lot horticultural farming activities, is done around them so it is assumed that these bacteria that degrade nitriles was present there also due to less competition in extremophiles environment. Collected samples was serial diluted on 2.5ml isobutyronitrile and 2.5ml butyronitrile media both containing 2µl vitamin B 12 and 250ml lake water. Spread plating and sub culturing was done on both media and incubated at 40°C for 7 days. Sixty pure isolates were obtained, characterized morphologically and biochemically 30 isolate were gram positive cocci.4 gram positive rod, one Gram negative and 25 were gram positive with spiral shape and were classified as actinomycetes. Seven isolates utilized CMC, ten utilized cellulose, sixteen utilized chitin, forty three utilized starch, nine utilized Xanthan, twenty three utilized skimmed milk, three utilized lignin and twenty seven utilized tween 20. Most isolates were small white or cream in color with regular shape but there were also yellow color with irregular shape or filamentous. One isolate (BN02) utilized seven substrates. The aim of the study was achieved because novel enzymes which can be used as biocatalytic were found. Lipases enzyme can be produced to be used in the degradation of oil in water.
Soil moisture variabillity across soil texture regimes in disturbed and nondisturbed areas of University of Embu in Embu county.
(University of Embu, 2019) Ahmed, Suleiman Ali
Soils are complex porous media comprising of minerals, water, air and organic matter. Soil serves as a media for growth of various types of plant and reservoir of the hydrological cycle. Soil moisture is the amount of water content in a soil at a given time while soil texture is the proportion of sand, silt and clay particles in a given soil .Soil moisture is affected by various factors such as soil structure, texture, organic matter content, density of soil, and temperature. This study is aimed at understanding of how soil moisture vary with texture, moisture is a critical component in the water cycle and its assessment is of paramount important in estimating water balance of a region. In agricultural production, the variability in soil moisture may be responsible for low or high crop yields as soil moisture affects nutrient absorption. Soil texture also affects the physical characteristics and behavior of the soil, such as water retention power of the soil, nutrients holding capacity and hence vulnerable to erosion. Research has shown that soil moisture content varies greatly with texture. Different soils have different moisture content with sandy soil retaining very little water while clay soil holds maximum water, thus understanding the concept helps taking appropriate measures in management practices to enhance conservation and maintenance of soil.
Extra-Cellular Enzyme Producing Fungi from Termite Nests at The University of Embu Soils
(University of Embu, 2019) Githu, Valentine Njeri
group of fungi are capable of degrading cellulose which is a complex polysaccharide of plants since they produce cellulase enzymes. The research on the isolation and determination of substrate degrading fungi isolated from termite nests at the University of Embu soils is important in learning the ecological significance of the various fungi in the decomposition process. Comparison of the rate of substrate degradation (Starch, cellulose, casein, CMC, lignin, tween twenty and chitin), various fungi aids in understanding the decomposition process. To determine this, nest samples were collected from the study sites and taken to the laboratory and various fungal isolation techniques were employed to obtain pure isolates using soil extract agar. Eighteen isolates were obtained named with codes as Isolate 001 to isolate 018. Morphological identification including mycelium color, colony characteristics and microscopic features were used when colonies were grown on various media (Malt extract, oat meal agar, actinomycetes agar and SDA). Biochemical tests were done to differentiate between the isolates ability to degrade various substrates and the optimum conditions required for growth. Isolates 004,005,006,009,010,011,012,016 showed positive results in degradation of various substrates. Therefore, the knowledge obtained in understanding the degradation mechanisms and process of complex molecules (cellulose) by fungi can be applied in the management of organic wastes from plants as well as utilization in industrial processes such as production of bioethanol.
Ground-dwelling insect species abundance and diversity in agricultural and non-disturbed landscapes at the University of Embu.
(University of Embu, 2019) Muthomi, Derrick Njiru
abitat transformations due to conversions of natural habitats to agricultural land are propelled by increasing human populations and demand for resources. While such changes have enabled man to optimally use available resources, they potentially undermine the capacity of ecosystems to perform their functions. Ultimately, it is the inhabitant populations and species of flora and fauna that suffer. However, little information and knowledge of insect species populations and composition makes reliable recommendation difficult. Our study surveyed insect species in two areas; agricultural and virgin landscapes using pitfall traps and revealed that the virgin landscapes had richer biodiversity. The composition of functional groups in the virgin landscape was also more balanced than that of the agricultural landscape showing better population regulation mechanisms. The findings reveal the linkages that exist between habitat characteristics and species composition as well as functional groups and population regulation.
Variability of soil moisture with time of the day in the University of Embu
(University of Embu, 2019) Njoki, Flora Gathoni
Soil moisture is a key variable in controlling the exchange of water and heat energy between the land surface and atmosphere through evaporation and transpiration. It is a critical hydrological component in various water transport systems such as evaporation, infiltration and lateral flow at hill slope scale. This research will be conducted at different sites within the university of Embu . It will involve measuring soil moisture at different time of the day and comparing the different rates at which different soil losses moisture. Soils samples will be taken in the forest patch near dam 5, within the agricultural land and some from the sports field. Soils will be sampled from the field using a soil auger and placed in an organic paper bag which will be tightened to avoid the loss of moisture as is transported to lab for measurement in the lab the weight of the crucibles will be recorded and approximately 40g of the soil will be placed into the crucible. The soil in the crucible will be oven dried at 105 c for 12 hours. The soil will be allowed to cool for 15 minutes and then weighed again. The difference between the moisture of fresh soils and that of the oven dried will be recorded and analysed gravimetrically. The data will be analysed using excel
Identification of Spittlebug Species Plant Hosts, Ecology and Their Syombiants within the University of Embu-Kenya
(University of Embu, 2019) Hallako, Margaret; Ogega, Evans Chacha S.
Spittlebugs a nymph stage of froghoppers that are insects of the family Cercopidae that inhabits strawberries, nursery stock, and legume forage crops, ornamental grasses. Meadow spittlebug, Philaenus spumarius is the most common insect species of spittlebug in the world. They taps into the plant, drinks the xylem sap and secretes the frothy spittle that provides nourishment and protects them against predators and dehydration. The creation of microhabitats is an important and efficient strategy used by insects to regulate their body temperature .The foam secreted can act as a repellent or irritant to the predators. There many spittlebugs species inhabiting the Kenyan ecosystem yet there is little information on, their ecological influence, abundance, habitat preferences, distribution and activities of spittlebug species. This study aims to identify spittlebug species, habitats and their ecology and document data that enable us to understand the role/niche they play in the University of Embu Ecosystem. The sample was collected in sealable sterilized bottles using a pair of sterilized forceps and transported to the zoology laboratory. Plant species inhabited by spittlebugs was collected and identified. Nutrient agar and potato dextrose agar media was prepared and autoclaved, allowed to cool after dispensing to petridishes. Spread plating culturing and sub-culturing was done on sterile laminar floor wood. The media used supports growth of wide range of bacteria and fungi. The contents of the midgut was cut and dissolved in normal saline, mixed well and subjected to serial dilution to 10 -3 before spread plating was done and plates incubated at 30°C for 12hrs. Sub-culturing was done to obtain pure isolated which was tested for colony characterization, substrate utilization and biochemical tests.
Bacteria Isolates from Microbial Mats in Lake Magadi with Potential for Substrate Utilization
(University of Embu, 2019) Kathure, Maureen Kinyua
Lake Magadi is an alkaline, hypersaline environment with extreme environmental conditions that allow specific microorganisms with specific characteristics to flourish. Its pH ranges from 9-11.5, very high temperatures, high salt concentrations (Na2CO3). Despite all the extreme conditions, this type of lake is the most productive aquatic environment in the world with productivity rates greater than the mean rate for all aquatic environments in the world. They are usually characterized by the presence of coloration of water caused by different microorganisms for instance the cyanobacteria. On the other hand microbial mats are microbial communities made up of a consortium of bacteria dominated by cyanobacteria. They are usually ubiquitous in nature and are found over the sediment surface or as floating masses in marine waters, hypersaline waters, estuaries, hot springs and deep oceans. Ecological success of microbial mats and their broad array of microbial activities suggest these microbial ecosystems might be useful in bioremediation of environmental pollutants and even bio generation of useful products. Since microbial mats contain both nitrogen fixing bacteria and photosynthetic bacteria, they usually tend to be self-sufficient with few growth requirements. The study was aimed to isolate useful bacteria from microbial mats from Lake Magadi with both biotechnological and therapeutic applications. This is because some of these bacteria can produce enzymes, proteases, antitumor and even antimicrobial agents for a variety of pathogens. Microbial mats were obtained from Lake Magadi and brought to the microbiology laboratory in the University of Embu. They were then heat treated to 100°C and 120°C. They were serial diluted and cultured in both actinomycetes agar and oatmeal agar and then incubated at temperatures ideal for their growth. After incubation 19 pure isolates were obtained from the study. Out of these only one isolate was able to utilize starch and only one could utilize cellulose. Thirteen isolates utilized tween 20 and 12 could utilize skimmed milk. No isolate utilized CMC, xanthan and lignin. Most of them were gram positives and even pathogenic. Few enzymes were identified and therefore further tests and research needs to be done for these extreme environments as there is a high diversity of microbes in the area.
Impact of human activities on soil organisms in University of Embu
(University of Embu, 2019) Owino, Cynthia Oloo
Soil organisms are organisms that are present in the soil. They comprise less than 1% of the total mass of the soil and play a vital role in supporting all plants. They require certain conditions in the soil in order to survive and to perform their functions. Some organisms have the ability to survive in areas with high temperatures and some survive in areas with low temperatures. The soil PH and availability of oxygen in the soil are some of the factors that affect survival of soil organisms. Some of the roles these organisms play in the soil have not been studied within the University of Embu. Moreover, conditions that influence the survival of these organisms have not been fully addressed. This study sought to address the impact of land practices on soil organisms. Four sites were selected for sample collection and from each of the four sites; five samples were taken for analysis. From the samples visible macro-organisms were identified and counted in the lab and the resultant data processed using Microsoft Excel. The results showed that earthworms, beetles, ants and millipedes were the commonly encountered organisms in the studied sites. Ants were the most abundant organisms in all the studied sites while the millipedes were the least abundant. The farm and dam 5 (5.0 and 4.8 respectively) had highest mean values of organisms while the university paths had the least at 1.5. The presence of many ants in the farm and dam five is an indication that nutrient cycling is achieved as the ants breakdown the humus in these sites. Also these two sites receive a lot of inputs which continually offer suitable habitats for microorganisms to thrive. On the other hand university paths are continuously swept and this leaves them bare. In that case they are likely to support very few organisms as witnessed in this study. The study concludes that human activities alters the soil physical properties such as soil temperature, air, soil Ph, temperature and organic matter content and these factors are crucial to the growth and survival of soil organisms. These factors when altered they affect the abundance and distribution of the soil organisms.
Evaluation of water pH levels in Dam one and five at the University of Embu, Kenya
(University of Embu, 2019) Ekeno, Jairus Napulo
Water pH levels in most aquatic sites have been compromised by introduction of modern technologies such as industries, mining, burning of fossil fuels and farming resulting in increased research interest in water quality due to anthropogenic pressure on water bodies. Despite research done on water pH in the dams at the University of Embu, there have been no studies on the pH levels in some dams. The main objective of this study was to assess the pH levels in dam one and dam five, including other physio-chemical parameters such as conductivity and temperature. In each dam, water samples were randomly collected from six points. The pH levels were determined using an Ohaus pH meter, conductivity and temperature were measured using conductivity meter. The data was subjected to one-way analysis of ANOVA using R software to determine the variations in pH level. The result of this study reveals that the physico-chemical parameters are within the maximum permissible limit (USEPA, 1976, 1986) with some significant variation in some parameters. Hence, water dam is safe and suitable for aquatic life survival and even irrigation. The results from this study provides information that will allow development and implementation of management strategies aimed at maintaining optimum pH level that is required for survival of aquatic life in the dams.
Lipase Production by Lipid Degradng Bacteria Species in Waste Water in Embu, Kenya
(University of Embu, 2019) Muthee, Evangeline Mueke
Lipids are hydrophobic non polar and made up of hydrocarbon chains. Lipid degrading bacteria are able to completely remove lipids in waste water by use of lipase enzyme. Other microorganisms such as yeast, bacteria and molds have been observed to be capable of degrading lipids completely. High lipid concentration contained in waste water cause clogging of sewage pipes and this in return results to overflowing of the sewage and bad odour produce by the waste in the environment. Lipids can be removed through physicochemical techniques although they are not completely removed and thus lipid degrading bacteria are required for complete removal of lipids. Since physicochemical processes used to remove the lipids in waste water treatment are costly, pollute the environment and do not completely remove some colloidal lipids there is need of using the lipid degrading bacteria which are more effective. The objectives of this study is to determine lipase production by lipid degrading bacteria species in waste water in Embu, Kenya, by isolating and purifying the lipid degrading bacteria species , determining conditions favourable for lipid degradation and accessing the rate and quantity of lipase production by the lipid degrading bacteria species. Media containing peptone water, agar and olive oil was used for enrichment of the bacteria. Serial dilution was done which was followed by colony counting .Identification of lipid degrading bacteria was carried out using biochemical test and Gram staining. The observed bacterial isolates were Gram positive, were able to utilize starch and xylose and some utilized citrate. They were also observed to produce catalase enzyme.
Assessment of Occurrence of Escherichia Coli from Dams at the University Of Embu
(University of Embu, 2019) Kirega, Dennis Mwangi
Water is a very important resource and therefore its quality should be monitored to ensure it is not contaminated. Water can be polluted by plastic material, chemical effluences and fecal matter. Fecal contamination from sewage linkage into water reservoirs like dams is a major issue that needs to be addressed because it affects important resources in our environment. Water contamination by fecal material can result in outbreaks of illness and renders contaminated water requiring extra processes to clean which may require an additional investment in capital. This study strives to identify which dams are polluted and whether they are fit for irrigation and for livestock rearing. E. coli occurrence in the dam water samples helps to in identification of fecal contamination as the bacteria is an indicator organism that helps in identification of pathogens associated with fecal matter contamination. The study involved the isolation and quantification of E. coli in the dam water at the University of Embu. Water samples from 3 dams at the University of Embu were collected and a colony count of the E. coli colonies isolated from the samples was analyzed to achieve the comparison of bacterial load among the dams to help evaluate which dam is most affected by pollution. This study addresses the need for clean and safe water from the dams for irrigation and livestock use. The study showed the level of pollution in the dams. The occurrence of E. coli in the water samples from the dams provided evidence of fecal contamination but the level of occurrence suggested only minimal contamination. This therefore implied that the dam water requires minimal disinfection in the form of chlorination before use for agricultural purposes.
Isolation and Characterisation of Cellulose Degrading Fungi from Dead Wood Sediments at The University of Embu Forest
(University of Embu, 2019) Ogero, Victor Omwoma
Degradation of cellulose by fungi is a scientifically established phenomenon. This research a successful isolated five fungal isolates named OV1, OV2, OV3 and OV4 were obtained from dead decaying wood at the University of Embu. Samples were collected from the forest and taken to the laboratory where different tests were performed. The isolates were exposed at p.H of 3.2, 8.5, and 7.0 whereby different growth characteristics were exhibited. Temperatures of 42 0 0 C, 10 0 C and 28 C were used in checking the degrading ability of these these isolates showed different degradation rates. Skimmed milk, citrate, starch, xylose and glycerol substrates were as well used as substrates to be utilized by this isolates. In this substrate utilization growth occurred in some and failed in other substrates. Morphological identification including mycelium color, colony characteristics and microscopic features were used when colonies were grown on PDA. Biochemical and physiological tests were as well done to differentiate between the isolates ability to degrade cellulose and the optimum conditions required for growth. of isolates.OV1 is postulated to belong to Beauveria spp, OV2 to Aspergillus spp, OV3 to Trichorderma spp and OV4 to Verticillium spp.. The research facilitated the acquisition of knowledge on the decomposition process that is aided by cellulose degrading fungi in the University of Embu forest. Therefore the knowledge obtained in understanding the degradation mechanisms and process of complex molecules (cellulose) by fungi can be applied in the management of organic wastes.
Isolation, Identification and Characterization of Cellulose Degrading Bacteria From the Soil in the Forest of University of Embu
(University of Embu, 2019) Muthanje, Eric Murimi
Cellulolytic bacteria are freely found in the soil and are responsible for degradation of cellulose. Cellulose occurs in a wide variety of living species from the worlds of plants, animals and bacteria as well as amoebas. Cellulose is degraded by cellulase enzyme which consists of three classes of soluble extracellular enzymes: endoglucanases, exoglucanases and betaglycosidases. The key objective of the study was to isolate, identify and characterize cellulolytic bacteria from the soil collected from a forest environment within the University of Embu. Soil samples were collected few meters from the main campus and taken to the laboratory. The soil samples were inoculated separately to obtain single bacterial isolates and grown in culture medium under favorable laboratory conditions. A total of five bacterial isolates namely X1, X2, X3, X4 and X5 were found likely to belong from the bacillus genus. Gram staining was done as the first step of identification and 3 bacterial isolates were found to be gram positive and two gram negative bacteria. Morphological identification included colony characteristics and microscopic features. Finally various biochemical tests were done to determine the isolates ability to degrade various substrates such as citrate and starch. This study shows that the forest soils of the University of Embu is potent source of celluloytic microbes that could be utilized in industrial and biotechnological research.
Starch Degrading Bacteria Species in Embu County, Kenya. A Case of Microhabitats in University of Embu Farm
(University of Embu, 2019) Njoroge, James Kimani
Starch is the most abundant storage polysaccharide of plants and the chief source of carbohydrates for humans and is therefore of considerable economic importance. The polysaccharide is deposited plants in the form of small insoluble particles called starch granules. They consist of chains of glucose molecules which are linked together by alpha-1, 4- and alpha-1, 6- glycosidic bonds giving rise to amylose and amylopectin respectively when hydrolyzed. Amylases are starch degrading enzymes obtained from several sources such as plants animals and microorganisms that have great significance in present day biotechnology. These enzymes have wide area of potential application including food processing, animal nutrition, beverage production, pharmaceutical, textile, detergent, paper and pulp, biofuel industries. Their applicability has been expanding due to the increasing interest in using agro industrial residues as substrates associated with the development of solid state fermentation technology. Starch is a very abundant and renewable feedstock and the need for minimizing the extent of environmental pollution. Availability of starch degrading microorganisms particularly bacteria serve as a resourceful alternative in the production of biofuel. Ability to degrade starch is used as a criterion for the determination of amylase production by a microorganism. The project involved carrying out various tests to determine morphological and biochemical characteristics, process optimization for amylase production that is, the carbon source, organic and inorganic nitrogen sources, pH and temperature. From the study six bacterial isolates were obtained namely J1, J2, J3, J4, J5 and J6. They belong to Bacillus genus based on the gram staining and appearance.
Estimation of Sedge Biomass around the dams at University of Embu, Kenya
(University of Embu, 2019) Simiyu, Enos; Githaiga, Michael N.
The role of vegetation as natural carbon sinks is widely acknowledged with many researchers focusing on understanding the carbon capture and storage in vegetation types and species. Wetlands are among the major carbon sinks and recent research reveal that they play important role in climate change mitigation. Despite this awareness, no research has focused on biomass estimation for the sedges in Embu County. This study aimed at estimating variation of biomass across sedges around the dams within the University of Embu. It evaluated variation in above ground and below ground biomass of the sedge vegetation, and the relationship between the two. Above ground biomass was obtained through harvesting shoot canopies while the below ground biomass was obtained by coring. One way ANOVA was used to compare the total biomasses across the sites. The mean values for the total biomass around dams 1, 2, 3, 4 and 5 were 4305.3, 4421.6, 3343.2, 3222.8 and 2702.4 gm 2 respectively. The mean values for above ground biomass around dams 1, 2, 3, 4 and 5 were 830.62, 796.74, 654.76, 628.75 and 207.50 -2 gm respectively. The mean values for below ground biomass around dams 1, 2, 3, 4 and 5 were 3468.9, 3624.9, 2690.5, 2554 and 2494.9 gm -2 respectively. There were significant differences in total biomass, above ground and below ground biomass accumulation across the zones (F (4, 24), = 14.13; P = 0.001), (F (4, 24) = 57.55; P = 0.001) and (F (4, 24) = 7.21; P = 0.001) respectively. There was a strong positive correlation between above ground and below ground biomass R=0.755. These findings are important as they enhance our knowledge on the contribution of wetland vegetation in carbon capture and storage and hence their role in climate change mitigation.
Effects of Pig Slurry Application on Plant Growth and Microbial Community Abundance
(University of Embu, 2019) Kinyua, Mary Wairimu
The use of pig slurry as an alternative source of soil nutrients to inorganic fertilizers has grown tremendously over the past few years. This study focused on determining the effect of the use of the pig slurry on the general plant growth. It also determined the effect the slurry has on soil microbial communities. The study site was JKUAT farm from which soil samples was collected. The slurry was obtained from a local farmer within Juja. The experiment was carried out in a greenhouse. Solanum nigram (managu) was grown and used to determine growth parameters (height, biomass, and leaf count). The study involved obtaining soil samples from the farm. The soil was the tested for its nutrient composition (nitrogen and phosphorus). The slurry was applied and the plant grown over a period of one month on the soil with pig slurry. Controls used were soil treated with DAP fertilizer and plain soil. During the one month, growth parameters were determined (plant height and leaf count). After the one month, soil nutrient composition was determined as well as microbial community counts through culturing. The results of the experiment showed significant difference in height (p=0.000095) at day 28, leaf count (p=0.00173) and the biomass of the Solanum nigram plants was not significantly difference (p=0.705) in all the treatments. The bacterial colonies increased in soil treated with pig slurry while fungal colonies decreased. This study shows that raw un-composted pig slurry did not have beneficial effects on plant-microbe interactions.
Determination of effect of water availability (during the dry season) on abudance of vachellia xanthophloea around dam 5 in Embu University, Embu county, Kenya
(University of Embu, 2019) Nga’ng’a, Mary Wanjiku
Water sources are an important feature in many terrestrial ecosystems as they provide continuity of the hydrological cycle in many aspects. They provide vapor that rises to form clouds and later fall as rain precipitation also, they store water that evaporates to form the vapor. Many living organisms, including plants are dependent on water for their development. The higher the primary productivity the higher the diversity as hypothesized in ecological laws. This explains why tropical ecosystems have more species diversity than desert ecosystems. Far from that, abundance of trees is partly determined by water availability in an area. Soil is from where plants derive the water that they utilize to perform various functions. Therefore, it is only right to consider soil water as a parameter to consider when checking whether water availability affects plant abundance. The only way that can determine the age of trees is dbh. It is used to show the developmental stages for tree species. Narrowing down the population to a particular age group of a tree species and ruling out the probability of difference in soil moisture will help determine whether distance from a water source determines abundance. Because older trees are nearer the water table level and younger tree abundance maybe determined by dispersal, theirabundance may be measured separately. Assuming that the climatic conditions and that their response is at the same level because they samples are from the same geographical area. This will help show importance and high value that water sources should be given or levelled at.
Isolation and Characterization of Bacterial Coliforms in Yoghurt Produced at The University of Embu Dairy Farm
(University of Embu, 2019) Wanyaga, Charity Wakonyu
his study aimed at isolating and characterizing bacterial coliforms in yoghurt produced at the University of Embu dairy farm. 250 ml yoghurt was used for experimentation at the microbiology laboratory(lab). MaCconkey agar was diluted in distilled water and placed it in the autoclave together with the plates to be used for sterilization. An antifungal (cycloheximide) was added into the media and the media was regulated to a pH of 7.2 by addition of sodium hydroxide. Serial dilution was carried out using a micropitte into 6 tubes forming the samples of the study. Pure cultures were isolated whereby 2.8g of nutrient agar was measured into plates and incubated to allow growth of pure cultures. Gram staining technique was carried out whereby sterile slides were labeled appropriately and used to make microbial smears from each pure culture. The smears on each slide were gently flooded with crystal violet and allowed to stand for 1 minute then rinsed with distilled water. Ethyl ethanol was applied by drop rinsed and finally safranin was flooded and allowed to stand for 1 min and rinsed with distilled water. The slides were allowed to dry then viewed under oil immersion using a compound microscope. Substrate utilization and biochemical tests were carried out to confirm the presence of bacterial coliforms and their ability to utilize nutrients. Pure isolates were stored at different temperatures and we observed their growth rate. In this study, four bacterial isolates namely 1, 2, 3 and 4 were isolated from the yoghurt sample after serial dilution. All isolates were found to be enteric bacteria since they were all able to grow and show visible colonies on macConkey agar. The bacterial isolates were identified to be gram negative rods after carrying out the gram staining. The isolates were able to utilize different substrates such as cellulose, skimmed milk, glycerol, starch and Simmons citrate. All isolates had positive growth at optimum temperatures. The result of this study concluded that there was presence of bacterial coliforms in the yoghurt produced in the university dairy farm. The results are thus significant to the health of the public, especially consumers of these brands of yoghurt. The study recommends that the university dairy farm should ensure that the yoghurt produced is within the recommended coliform bacterial count appropriate for human consumption and to avoid spoilage.
Cellulolytic Bacteria in Rumen Contents of Carcasses from Majimbo Abattoir in Embu County Kenya
(University of Embu, 2019) Kenson, Fausto M.
Cellulose is a biopolymer that is found widely distributed on earth and it is a constituent of the plant cell walls and some algae. Cellulose hydrolyzing bacteria are adapted well to the environments containing cellulose biomass. The rumen of the ruminants can serve as an ideal source of cellulolytic bacteria since they help in the digestion of the cellulose in their feeds. Other cellulolytic microorganisms are the protozoa and fungi but bacteria constitutes the majority in the rumen. These bacteria that are able to degrade cellulose, can be utilized or rather applied in the clothing and fiber industry for the partial or complete synthesis of clothing and fiber materials. They can also be used in the environmental cleanup of the environments polluted with cellulose biomass. The main aim of the study was to explore the rumen content for the presence of the cellulolytic bacteria. The screening was able to determine the diversity of the cellulolytic bacteria in the rumen contents of the cattle in Majimbo abattoir and also helped determine the diversity of the substrates that these bacteria were able to utilize as sole carbon sources. Enumeration of these cellulolytic bacteria entailed spread plating in cellulose agar. The colonies grew differently were seperated and cultured in fresh cellulose media. The streaked plates were cultured until pure cultures were obtained. The isolates were screened for utilization of selected sole carbon sources. Those negative for cellulolytic activity test were considered non-cellulose hydrolyzing. The morphological was done on the isolates to determine their characteristics. This research generated bacterial isolates that can be utilized for degradation of cellulosic biomass. In addition, the isolates would act as bioresource for future studies. There were thirty isolates from the four samples. Three of the isolates (A308, D316 and C328) were Gram negative with the other twenty isolates being Gram positive. The morphological features showed that there were rods and cocci with only two isolates (B301 and A321) being rods and the rest being cocci. After screening the isolates for the utilization of various selected substrates they showed to be able to utilize a number of them but at varying extents. The cellulolytic bacteria are the ones that were able to utilize cellulose and CMC as sole source of carbon. CMC is made up of cellulose molecules and it is more complex in terms of the structure as compared to cellulose.

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