ABSTRACT
Endoglucanase (EC3.2.1.4) from sorghum (S. bi-color) and millet (Pennisetum typhoides & Digitaria exilis) malts were purified to homogeneity through the methods of ammonium sulphate precipitation and gel filtration. Molecular mass of 35 KDa and 41 KDa were determined by SDS-PAGE. The purified enzymes catalyzed the hydrolysis of carboxy-methylcellulose with optimum activity at pH of 4.8, 5.0, 6.0, and temperature of 60ºC, 60ºC and 70ºC for Digitaria exilis, S. bi-color and Pennisetum typhoides respectively. More than 90% activity was retained in S. bi-color and Pennisetum typhoides and 73% activity in Digitaria exilis after 1.0 hour pre-incubation at 60ºC. Km values of 0.11, 0.09, 0.20 mM and Vmax 17.53, 15.0 and 11.10 U/mg/min were obtained for S. bi-color, Pennisetum typhoides and Digitaria exilis respectively. Co2+ inhibited endoglucanase activity whereas Ca2+, Ba2+, and Zn2+ enhanced enzyme activity. The enzyme was inactivated by glucose, a major end product of cellulose hydrolysis. Results indicate that endoglucanase of S. bi-color and Pennisetum typhoides are more suitable for malting and a blend of the two will produce high quality malt.
ABSTRACT
Effect of electromagnetic radiations (EMR) from mobile phones on some soil bacterial (Bacillus, Micrococcus, Staphylococcus, Corynebacterium and Enterococcus) and fungi (Saccharomyces, Penicillium and Geotrichum) strains were studied. At the study periods of 0, 30, 60, and 90 days, the total colony counts (CFU/g) and viability ratios of Bacteria and fungi strains were determined on both the EMR unexposed and exposed soil samples. At the exposure periods of 30, 60, and 90 days, the mean total colony counts of all the organisms in the EMR exposed samples were statistically (p<0.05) lower than those of the EMR unexposed samples. The percentage changes in total colony counts of the EMR unexposed and exposed soil samples between 0 to 90 days for Bacillus, Micrococcus, Staphylococcus, Corynebacterium, Enterococcus, Saccharomyces, Penicillium and Geotrichum were 2.54% and -70.51%, 33.18% and -75.80%, 11.79% and -63.93%, 20.12% and -91.96%, 30.00% and -98.94%, 62.36% and -61.06%, 42.40% and -100%, and 50.46% and -78.48% respectively. These show that Staphylococcus and Saccharomyces strains being the most resistant, while Enterococcus and Penicillium were the most susceptible strains. The results generally indicate that EMR has negative impacts on both Bacteria and fungi total colony counts.