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Aug 25, 2004Keywords:
Azotobacter bacteria cassava waste biochemical changes nitrogen fractions solid state fermentation
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Effect of Selected Azotobacter Bacterial Strains on the Enrichment of Cassava Waste during Sold State Fermentation
Abstract
Target Audience: Local farmers, Livestock researchers, microbiologist
The effect of three different strains of Azotobacter bacteria in solid substrate fermentation on cassava waste was evaluated. The substrate was incubated at 300c for 10 days inoculation with the Azotobacter bacteria species. One non-inoculated batch was incubated as a reference. Percentages of the initial and final proximate contents were analysed. The experiment was carried out in quadruplicate. Inoculation of cassava waste with species of Azotobacter bacteria significantly increased the levels of the crude protein content to a mean (0.58 + SE) of 11.3% of the initial value. Among the tested species Azotobacter agilii increased the crude protein level most effectively, followed by Azotobacter vinelandii and least for Azotobacter beijerinckii. The increased crude protein was significantly correlated (r = 0.86) with the extent of fermentation. The non-protein nitrogen content increased significantly (P < 0.05) to a mean of 5.23% while the total nitrogen followed similar trend. The hemicellulose content was higher for Azotobacter agilii and Azotobacter vinelandii compared with Azotobacter beijerinckii while the lignin content was lowest for Azotobacter Vinelandii and Azotobacter agilii than the control sample. The energy level was increased in the bacteria treated substrates than the control sample. It is concluded that both incubation and bacterial activity are instrumental in increasing the potential protein, hemicellulose and energy content of cassava waste during solid substrate fermentation and the efficacy depends on the species of bacterial used.
Key Words: Azotobacter bacteria, cassava waste, biochemical changes, nitrogen fractions, solid state fermentation.
Trop. J. Anim. Sci. Vol.6(1) 2003: 1-7
The effect of three different strains of Azotobacter bacteria in solid substrate fermentation on cassava waste was evaluated. The substrate was incubated at 300c for 10 days inoculation with the Azotobacter bacteria species. One non-inoculated batch was incubated as a reference. Percentages of the initial and final proximate contents were analysed. The experiment was carried out in quadruplicate. Inoculation of cassava waste with species of Azotobacter bacteria significantly increased the levels of the crude protein content to a mean (0.58 + SE) of 11.3% of the initial value. Among the tested species Azotobacter agilii increased the crude protein level most effectively, followed by Azotobacter vinelandii and least for Azotobacter beijerinckii. The increased crude protein was significantly correlated (r = 0.86) with the extent of fermentation. The non-protein nitrogen content increased significantly (P < 0.05) to a mean of 5.23% while the total nitrogen followed similar trend. The hemicellulose content was higher for Azotobacter agilii and Azotobacter vinelandii compared with Azotobacter beijerinckii while the lignin content was lowest for Azotobacter Vinelandii and Azotobacter agilii than the control sample. The energy level was increased in the bacteria treated substrates than the control sample. It is concluded that both incubation and bacterial activity are instrumental in increasing the potential protein, hemicellulose and energy content of cassava waste during solid substrate fermentation and the efficacy depends on the species of bacterial used.
Key Words: Azotobacter bacteria, cassava waste, biochemical changes, nitrogen fractions, solid state fermentation.
Trop. J. Anim. Sci. Vol.6(1) 2003: 1-7
