Browsing by Author "Muigai, A."

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    Isolation and characterization of bacillus species from soil in Ngere tea catchment area of Murang’a county, Kenya
    (2014-07) Wafula, Eliud N.; Kinyua, J.; Karuiki, D.; Muigai, A.; Mwirichia, Romano K.
    Bacteria are a very diverse group of organisms in soil, and major taxonomic groups are represented in most soils. The extent of the diversity of microorganisms in soil is seen to be critical to the maintenance of soil health and quality, since a wide range of bacteria are involved in the important soil functions. The objectives of this study were to isolate, characterise and identify groups of bacteria from Bacillus species that are associated with soil quality in tea growing areas of Ngere. 10 isolates were obtained using dilute nutrient broth agar and the bacterial morphology was identified as gram-positive rod-shaped bacteria, they grew well at pH ranging from 5 6.5 and temperature range of 25o C 35o C. Based on different biochemical tests and sequence of 16S rDNA, the isolated bacteria were identified as belonging to genus Bacillus. Phylogenetic analysis of isolates D61, D19, and, D51, suggested that they were closely related to Bacillus cereus with 89-96% rDNA sequence analysis similarity while isolates D5, D16, S31, D70 and D2 were closely related to Bacillus thuringiensis with 83% - 96% rDNA sequence analysis similarity. Isolate S30 was closely related to Bacillus subtilis with 99% rDNA sequence analysis similarity and isolate D29 was closely related to Bacillus mycoides with 97% rDNA sequence analysis similarity. Given the low similarity values some isolates had to their closest relatives, chances are high that Ngere tea catchment area harbours a diverse population of as yet, uncultured and uncharacterized microbes.
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    Isolation and characterization of bacteria isolates from soil feeding termites and soil from Juja and Kakamega forest in Kenya
    (2010) Ntabo, R.; Boga, Hamadi I.; Muigai, A.; Mwirichia, R.
    In the last several years information on the gut ecosystem of termites has continued to be gathered. Most studies have been focused on wood feeding termites but studies on soil feeders remain sparse owing to their difficulty of establishing permanent laboratory cultures. The aim of this study was to isolate, characterize and identify bacteria resident in the soil feeding termite gut, mound and parent soil of Cubitermes species with the potential to produce antibiotics and enzymes for industrialization. The samples were collected from kakamega forest from two sites Kalunya Glade and Lirhanda Hill. The study was also extended to the soils found in Juja. Hundred and thirty seven (137) isolates were cultivated and isolated using dilute nutrient agar media and screened for their antagonistic effects on various test organisms. Fifty one percent of the isolates were antagonist to Escherichia coli. Fifty seven percent of the isolates were antagonists to Bacillus subtilis while 55% of the isolates were antagonist to Candida albicans. Enzymatic activities of the isolates showed that 65% of the total isolates were starch degraders, 54% were casein degraders and 68% of the isolates were able to liquefy gelatin. Eleven percent of the isolates were cellulose degraders the majority of which were obtained from termite gut and mound. Isolates from Juja soil had the highest number of non degraders as compared to Kakamega Forest soils. The isolates were characterized using morphological, biochemical and molecular methods. Phylogenetic analysis of amplified 16S rRNA gene sequence revealed majority of the isolates were closely related to Bacillus and Brachybacterium species and had showed invitro antagonistic effects. Gram negative bacterial isolates obtained were closely related to Pseudomonas species. In conclusion, the isolates were potential antibiotic producers with varying ability to degrade gelatin, casein, and cellulose an indication of the role they play in their habitat