Screening and optimization of cellulolytic activity of local microbial isolates in the Egyptian Delta region.

Abstract

Twenty locations of different plant and soil samples were surveyed for microorganisms of cellulolytic activity. A total of 20 bacterial and 20 fungal isolates were collected, cultivated, purified and tested for cellulose degradation. The most efficient cellulase producers were the fungal and bacterial isolates from grape leaves; which were identified as Aspergillus flavus MH591448 and Pseudomonas aeruginosa KX610179. A more detailed study for optimization of growth conditions for the highest cellulase activity was performed for the higher cellulose-degrading isolates, namely: Aspergillus flavus, Fusarium oxysporum, Pseudomonas aeruginosa and Klebsiella aerogenes. The maximum growth and cellulolytic activity of the tested microorganisms was obtained for cultures on minimal salt nutrition medium, incubations temperature of 35°C, with initial pH value = 6, by adding ammonium sulfate as a supporting nitrogen source, without additive co-carbon source, after incubation for 2 days for bacterial isolates and 5 days for fungal isolates on a shaking incubator of 80 rpm.