Document Type : Original Article
Authors
1
Botany and microbiology Department, Faculty of Science, Sohag University, Sohag, Egypt
2
Chemistry Department, Faculty of Science, Sohag University, Sohag, Egypt
3
Microbiology Department, Soil, Water and Envir. institute, Agric. research center, Giza, Egypt
10.18576/jpac/040201
Abstract
As a result of the magnitude of the problem of the accumulation of agricultural wastes and increase the environment and economic problems caused of it . It was necessary to find a scientific solution to face this problem and convert these wastes to high-value products , by using microbial organisms such as bacteria .Corn cobs have been chosen from shandawil research station in sohag governorate as an example of agriculture wastes and has been treated by physical and chemical methods to remove lignin and retain cellulose and hemicellulose free of any impurities. One hundred bacterial isolates, isolated from Water, Soil and cow dung in Sohag governorate, 6 isolates from cow dung were tested for their ability to produce extracellular Cellulases and hemicellulases, of all these 6 isolates isolate number (41 had the highest potential for celluolytic and hemicelluolytic activity was chosen. From various morphological, biochemical and 16S rRNA, the isolate was identified to be Bacillus cereus LAZ 518. Physiological studies were conducted to determine the optimum cultural conditions for maximum cellulases and hemicellulases production by Bacillus Cereus LAZ 518. The highest enzyme yield was obtained after 48 hours incubation at 50 °C and pH 7.0 when corn cobs was used as sole carbon source, respectively Carboxymethyl cellulose (CMC) was found to be a good inducer for cellulases and hemicellulases production . High level of enzyme production was obtained with the addition of yeast extract as a nitrogen source at concentration of 0.1 %. Tween-80 as an addition to medium inceases enzymes production. When examining the properties of cellulases and hemicellulases it was found that enzymes had a high degree of constancy at a temperature 70° C and pH 5 and improved performance when added with elements such as cobalt, calcium, sodium, potassium, and substances such as urea ,EDTA , β-mercaptoethanol , Tween-60 ,Tween- 80 and oxidizing agents such as hydrogen peroxide and sodium peroxide , it has been found that enzymes were strongly inhibited when added with mercury or high concentrations of oxidizing agents and surfactants.
Keywords
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