Browsing by Author "Karanja, Anncarol W."

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    Assessment of Physicochemical Changes during Composting Rice Straw with Chicken and Donkey Manure
    (Springer Science + Business Media, 2019) Karanja, Anncarol W.; Njeru, Ezekiel M.; Maingi, John M.
    Purpose Traditional methods of composting are limited in timely production of good-quality compost due to recalcitrant nature of materials of plant origin. This study focused on evaluating the use chicken and donkey manure as starter cultures to biostimulate bioconversion of rice straw into bioorganic fertilizer. Use of starter cultures would enhance composting as a strategy for rice straw management to enhance soil fertilization and reduce environmental pollution. Methods In this study, chicken manure and donkey manure were used as starter cultures to enhance bioconversion of recalcitrant and abundant rice straw in Mwea, the main rice-producing area in Kenya. Treatments of the study included rice straw co-composted with chicken manure (T1), rice straw co-composted with donkey manure (T2) and a control (T0) consisting of un-treated rice straw. Temperature, pH and electrical conductivity (EC) were monitored throughout the composting period. Resultant compost types were characterized in respect to their macro-nutrient concentrations, cation exchange capacity, pH and heavy metal content. Results Levels of temperature, pH and EC among the treatments of the study revealed signifcant diferences at 5% level of confdence using Tukey’s test. The three resultant compost types obtained were also physicochemically diferent as revealed by analysis of variance of cation exchange capacity, phosphorus, nitrogen and carbon content. Conclusion Results indicated that use of chicken and donkey manure signifcantly improved the composting process and the quality of resultant compost.
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    Assessment of Physicochemical Changes During Composting Rice Straw With Chicken and Donkey Manure
    (Springer, 2019) Karanja, Anncarol W.; Njeru, Ezekiel M.; Maingi, John M.
    Purpose Traditional methods of composting are limited in timely production of good-quality compost due to recalcitrant nature of materials of plant origin. This study focused on evaluating the use chicken and donkey manure as starter cultures to biostimulate bioconversion of rice straw into bioorganic fertilizer. Use of starter cultures would enhance composting as a strategy for rice straw management to enhance soil fertilization and reduce environmental pollution. Methods In this study, chicken manure and donkey manure were used as starter cultures to enhance bioconversion of recalcitrant and abundant rice straw in Mwea, the main rice-producing area in Kenya. Treatments of the study included rice straw co-composted with chicken manure (T1), rice straw co-composted with donkey manure (T2) and a control (T0) consisting of un-treated rice straw. Temperature, pH and electrical conductivity (EC) were monitored throughout the composting period. Resultant compost types were characterized in respect to their macro-nutrient concentrations, cation exchange capacity, pH and heavy metal content. Results Levels of temperature, pH and EC among the treatments of the study revealed signifcant diferences at 5% level of confdence using Tukey’s test. The three resultant compost types obtained were also physicochemically diferent as revealed by analysis of variance of cation exchange capacity, phosphorus, nitrogen and carbon content. Conclusion Results indicated that use of chicken and donkey manure signifcantly improved the composting process and the quality of resultant compost.
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    Endophytic Bacillus aerophilus from the Leaves of Azadirachta indica as a Potential Biocontrol against Staphylococcus aureus
    (Journal of Advances in Microbiology, 2023) Mwendwa, Peter Kasyula; Karanja, Anncarol W.; Maingi, John M.
    The study entailed isolation and identification of Bacillus aerophilus in the leaves of young Azadirachta indica plants, establishing the antimicrobial activity of the endophyte against Staphylococcus aureus, and screening for phytochemicals. The study investigated the potential of the endophytic Bacillus aerophilus in pathogen inhibition and phytochemical screening for bioactive compounds produced by the endophyte that can be used in drug development. The research contributes to the wider scientific goal of curbing rising cases of antibiotic resistance. Place and Duration of Study: Sample: collected from Kanyonyoo in Kitui County, between August 2022 and June 2023. Methodology: The bacteria were aseptically isolated and sub-cultured on nutrient agar. For identification, the bacteria underwent biochemical tests and molecular characterization. The 16S rRNA region was amplified and sequenced using universal primers 27F and 1492R. Bacterial isolate K1L003 was identified as Bacillus aerophilus. For antimicrobial testing, the agar disk diffusion method was used against pathogenic Staphylococcus aureus on Mueller Hinton Agar plates (MHA). The controls were doxycycline and vancomycin. Results: The endophytic isolate only inhibited Staphylococcus aureus (P < .001), with an inhibition mean similar to doxycycline (26 mm), against the pathogen. The endophytic isolate produced terpenoids, saponins, alkaloids, and flavonoids. Conclusion: Endophytic Bacillus aerophilus has better antimicrobial inhibition potential than vancomycin, against Staphylococcus aureus and produces diverse bioactive secondary metabolites. The endophyte has the potential to produce compounds that are useful in treating drug-resistant Staphylococcal infections.
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    Rapid Bioconversion of Rice Straw Using Cellulolytic Cultures for Improved and Sustainable Crop Productivity and Soil Fertility in Mwea, Kenya
    (Kenyatta University, 2018) Karanja, Anncarol W.
    Proper management strategies for huge amounts of crop residue generated from agricultural farms need to be obtained. Composting is a good strategy in rice straw management. Traditional methods of composting rice straw are limited in timely production of good quality compost due to its recalcitrant nature. There is need to develop and formulate microbial starter cultures that are adapted to local climatic conditions to ensure efficiency in using microorganisms in composting. This study aimed at assessing and presenting appropriate starter cultures for bioconverting rice straw into bioorganic fertilizer for use in crop production. Bacteria and fungi with lignocellulolytic potential were isolated and used alongside other starter cultures to enhance bioconversion of recalcitrant and abundant rice straw in Mwea, the main rice producing area in Kenya. The microbial isolates were selected through screening procedures and then characterized morphologically, biochemically and genetically. Rice straw was composted by treating it with the selected microorganisms, chicken droppings, commercial effective microorganisms and donkey dung in separate setups. The resultant compost types were characterized in respect to their maturity, heavy metal content and nutrient concentrations. Changes in microbial population densities and diversity during a natural composting process were also studied. The lignocellulolytic microorganisms selected for use in composting the rice straw in this study included 20 bacterial and 11 fungal isolates. Results from various identification techniques used showed that most of the bacterial isolates belonged to Genus Bacillus while most of the fungi were mainly in Genus Trichoderma. Mean values for temperature, pH and electrical conductivity (EC) among the five treatments of the study revealed significant differences at 5 % level of confidence. Using the starter cultures of the study, composting the rice straw was successfully completed within 62 days. The five compost types produced by the composting experiments were physicochemically different as demonstrated by the significant differences revealed by analysis of variance (ANOVA) of their cation exchange capacity, phosphorus, nitrogen and carbon content. The composts were observed to have attained biological maturity as revealed by the germination index, plant growth index and C: N ratio values recorded. Microbial analysis of compost samples taken from the natural composting experiment indicated notable variations in the number of bacterial cells at different phases of composting ranging from 8.7 x 105 to 2.1 x 106 CFU/ g. It was observed that fungi were less prevalent in the compost during the thermophilic phase with a lower overall prevalence compared to bacteria. Bacteria were most predominant in the compost having 28 different bacterial isolates against 17 fungal isolates. Results indicated that addition of the selected lignocellulolytic bacteria and fungi and various starter cultures significantly improved the composting process and the quality of the resultant composts. The experiment on natural composting process showed that variations in microbial population densities and diversity correspond to fluctuations in temperature within the composting materials. From the findings of this study, it is recommended that the obtained lignocelluloytic microorganisms be formulated and used for composting plant residue and other organic wastes to enhance the composting process and improve the quality of resultant bioorganic fertilizers.