Production, Purification and Characterization of Cellulose from Local Isolate of Pantoea spp

Soil samples from fields cultivated with barley and wheat in addition to samples from spoiled orange and apple fruits and carrot roots were collected with the aim to isolate cellulase producing bacterial strains. Bacterial isolates obtained from these samples were grown on a selective medium containing carboxymethyl cellulose (CMC) as a sole source for carbon and energy. Results showed that nine isolates out of fifty were able to produce cellulase.The specific activity of cellulase in culture filtrate of the most efficient isolate was 1.601 u/mg protein.This isolate was identified according to its morphological characteristics and biochemical tests, and then by using Api 20-E and VITEK-II identification systems and was identified as Pantoea dispersa. Cellulase produced by P. dispersa was purified throughout four purification steps including ammonium sulfate precipitation, dialysis followed by purification with ion exchange chromatography using DEAE-cellulose, and then gel filtration throughout sephadex-G200. Purification results showed that the specific activity of the purified enzyme was 1181.8 u/mg protein with a purification fold and yield 115.2 and 26.6% respectively. Purified cellulase from Pantoea dispersa was well characterized by studying some enzyme characteristics. The molecular weight of cellulase was 15148 dalton, and pH 7.0 was the optimum for enzyme activity and stability, while 30 ºC was the optimum for enzyme activity and stability.