Xylan-hydrolysing enzymes from Streptomyces spp

Screening of some mesophilic species of Streptomyces indicated that enzyme activities capable of removing O-acetyl, arabinosyl, 4-O-methylglucuronyl, and feruloyl substituents from xylan were present in culture filtrates, in addition to endo-β-(1,4)-xylanases. Low constitutive levels of acetyl xylan esterase, arabinosidase, 4-O-methylglucuronidase, and ferulic acid esterase could be greatly elevated by supplementation of liquid media with starch-free wheat bran, oat spelts xylan, or sugar cane bagasse. One organism, S. olivochromogenes, produced particularly high levels of acetyl xylan esterase, ferulic acid esterase, arabinosidase, and 4-O-methylglucuronidase as well as endo-β-(1,4)-xylanase. Partial purification of extracellular preparations from S. flavogriseus and S. olivochromogenes disclosed the presence of multiple forms of both anionic and cationic enzyme activities. Several of the hydrolysing activities occurred as “families” in association with endo-β-(1,4)-xylanase.