Comparative study of some microbial arabinan-degrading enzymes

Abstract

A variety of thermophilic organisms and Bacillus species were screened in shake flask culture for arabanase and p-nitrophenyl-α-l-arabinosidase activities. Highest arabanase activity was produced by strains of Thielavia terrestris and Sporotrichum cellulophilum. Thermoascus aurantiacus and several Bacillus species were most active producers of arabinosidase. Arabinosidases from Bacillus strains had pH optima in the range 5.9-6.7. pH optima of fungal arabinosidases ranged from ≤2.9 to 6.7. Bacillus arabanases had neutral pH optima, whereas fungal arabanases had pH optima in the range 3.7-5.1. In general, arabinosidases were found to be relatively thermostable, retaining >70% activity for 3 h at 60°C. The T. aurantiacus enzyme retained 98% activity at 70°C after 3 h. Bacillus arabanases were relatively unstable. All fungal arabanases except the T. aurantiacus enzyme were fully denatured at 70°C after 3 h. © 1989 Society for Industrial Microbiology.