The current study aimed to optimize the production of cellulase and chitinase enzymes by plant growth promoting rhizobacteria (PGPR). Bacteria were pre-isolated from soil and identified as; Pseudomonas fluorescens NBRC (KW1), Serratia liquefaciens ATCC 27592 (EW1), Bacillus subtilis SBMP4 (EF1) and Bacillus megaterium NBRC 15308 (TF2). The effect of different growth parameters including; pH, temperature, carbon and nitrogen sources, and incubation periods were optimized for production of

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... se and chitinase enzymes by the selected bacterial strains. Three strains mainly, B. subtilis SBMP4, S. liquefaciens ATCC 27592 and P. fluorescens NBRC) recorded positive results for cellulase production. B. subtilis SBMP4 (EF1) and S. liquefaciens ATCC 27592 (EW1) strains demonstrated significant ability to produce cellulase at 40°C, while P. fluorescens NBRC (KW1) strain showed the maximum enzyme production at 30°C. Carboxymethyl cellulose gave the highest cellulase production compared to the other carbon sources. Chitinase enzyme was optimally produced by B. subtilis SBMP4 and S. liquefaciens ATCC 27592 strains under primary screening. B. subtilis SBMP4 had the strongest ability to produce chitinase at 40 o C, while S. liquefaciens ATCC 27592 at 30 o C. The optimum pH observed was at pH 6.0 to get the maximum chitinase production by S. liquefaciens ATCC 27592. Potassium nitrate (KNO 3 ) as an inorganic nitrogen source presented the highest chitinase production by B. subtilis SBMP4, whereas yeast extract demonstrated significant chitinase production by S. liquefaciens ATCC 27592. Mashhoor, W.A.; Nasr, S.A.; Sharaf, M.S. and Abdel-Azeem, H.H. (2009). Nutritional and environmental factors affecting cellulase production by two strains of cellulolytic Bacilli.