摘要:Abstract The present study was intended to investigate the effect of different physico-chemical parameters that included pH (3–11), temperature (4–60°C), incubation period (2–8days) and NaCl (1–10% w/v) concentration on the growth and cellulase enzyme production of the actinomycete strain St-1, to optimize its enzyme productivity. The strain St-1 isolated locally from soil sample and identified as Streptomyces griseorubens at MTCC and Gene Bank, Chandigarh, India (Accession No. AB184139), showed an optimum growth at pH 7, temperature of 45°C and 6days of incubation period. The cellulose hydrolysis by the isolate was also optimum at these parameters when the maximum level of reducing sugar produced due to filter paper activity was 5.6mg per mL and CMC activity was 4.5mg per mL. The isolate was moderately halophilic, as it was unable to grow beyond 6% of NaCl (w/v) concentration.