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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2930

Title: Cattle blood as a suitable medium for cultivating Bacillus sphaericus
Authors: Okoree, Eric Amaning
Issue Date: 15-Feb-1999
Series/Report no.: 2725;
Abstract: The large scale production of microorganisms depends on the suitability of the medium, its availability, cost and easy method of preparation. For culturing a species known to be suitable for insecticidal actions, protein as a basal medium is necessary. One of such rich basal media is blood. Cattle blood, a noted environmental pollutant, was used as a growth medium for the preparation of an effective bacterial insecticide, Bacillus sphaericus. Blood was selected for this study because of its high nutrient content, availability and low cost. Its growth and sporulation supporting capabilities for the test organism were compared with nutrient medium as the standard. The serum fraction in the blood was used as the main medium. Using Bacillus sphaericus strain IAB 1520, the medium was first compared with the standard in a pilot test to assess the general extent of comparison. Among various dilutions of serum tested against the standard medium, the 12.5% dilution was found to perform closest to the standard. It was therefore adopted for detailed study, which involved: plate counting, spectrophotometric measurements, colony diameter measurements and median lethal concentration determination. Colony counting units (CFU) of 3.7 x 107 were counted for the serum medium; the highest absorbance obtained was 1.94. The maximum colony diameter obtained was 22.7mm. Median lethal concentration of 1 o” was obtained from a log-probit graph sheet. Chi-square analyses of this value proved the serum medium efficacious. All the nutrients required by the bacterium were identified in the two media. In all cases, higher values were recorded in the serum broth. Sodium, however, was higher in the nutrient broth than in the serum broth. Finally it was observed that, as the price of the commercial nutrient media keep on increasing, the cattle blood on the other hand, could be obtained free of charge. This makes it relatively cheaper.
Description: A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirement for the award of the Degree of Master of Science, 1999
URI: http://hdl.handle.net/123456789/2930
Appears in Collections:College of Science

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