Thermostable, alkalophilic and cellulase free xylanase production by Thermoactinomyces thalophilus subgroup C

Thermoactinomyces thalophilus produced cellulase free extracellular endo-1,4-β-xylanase (EC 3.2.1.8) at 50°C and pH 8.5. Maximum xylanase production was achieved in fermentation medium using birchwood xylan as substrate after 96 h of growth at 50°C. Other agricultural substrates such as wheat bran, wheat straw, sugarcane bagasse and cornstover produced less xylanase. The crude enzyme preparation from mutant T. thalophilus P2 grown under optimised fermentation conditions showed no cellulase contamination and maximum xylanase activity of 42 U/ml at 65%deg;C and pH 8.5–9.0. This enzyme with initial xylanase activity of 42 U/ml was found thermostable up to 65°C and retaining 50% of its activity after its incubation for 125 min at 65°C.