Aims:  To determine the effect of environmental conditions on the production of extracellular lignocellulose‐degrading enzymes by Streptomyces sp. F2621 and to assess the potential use of these enzymes in the hydrolysis of lignocellulose material. Methods and Results:  The production of extracellular lignocellulose‐degrading enzymes, endoxylanase, endoglucanase and peroxidase during the growth of Streptomyces sp. F2621 in basal salts‐yeast extract medium containing different carbon sources and the effect of a number of environmental parameters (e.g. carbon sources and concentrations, pH and temperature) were investigated. The highest endoxylanase (22·41 U ml−1) and peroxidase (0·58 U ml−1) activities were obtained after 2–4 days of incubation at 30°C in a basal salts medium containing 0·4% (w/v) oat spelt xylan and 0·6% (w/v) yeast extract, corresponding to C : N ratio of 6 : 1. Cell‐free extracellular enzyme preparations from the strain were capable of releasing both sugar and aromatic compounds during incubation with eucalyptus paper pulp, straw and xylan. Overall, 9·3% hydrolysis of xylan occurred after 24‐h incubation. However the rates of hydrolysis of paper pulp and straw were approximately twofold less than xylan hydrolysis, although the total percentage hydrolysis of available substrate (24·5% and 16·3%, respectively) was greater than xylan hydrolysis. Conclusions:  The high levels of enzyme production achieved under batch cultivation conditions, coupled with no significant production of endoglucanase during the growth phase of organism and the release of both sugar and aromatic compounds from paper pulp and straw signify the suitability for these enzymes for industrial applications such as pulp and paper production. Significance and Impact of the Study:  The results highlight the environmental conditions for the production of extracellular lignocellulose‐degrading enzymes by Streptomyces sp. F2621 and suggest the use of streptomycetes and/or their enzymes in industrial processes.

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Aims: To determine and quantify the products from the degradation of xylan by a range of purified xylandegrading enzymes, endoxylanase, b-xylosidase and a-L L-arabinofuranosidase produced extracellularly by Thermomonospora fusca BD25. Methods and Results: The amounts of reducing sugars released from oat-spelt xylan by the actions of endoxylanase, b-xylosidase and a-L L-arabinofuranosidase were equal to 28AE1, 4AE6 and 7% hydrolysis (as xylose equivalents) of the substrate used, respectively. However, addition of b-xylosidase and a-L L-arabinofuranosidase preparation to endoxylanase significantly enhanced (70 and 20% respectively) the action of endoxylanase on the substrate. The combination of purified endoxylanase, b-xylosidase and a-L L-arabinofuranosidase preparations produced a greater sugar yield (58AE6% hydrolysis) and enhanced the total reducing sugar yield by around 50%. The main xylooligosaccharide products released using the action of endoxylanase alone on oat-spelt xylan were identified as xylobiose and xylopentose. a-L L-Arabinofuranosidase was able to release arabinose and xylobiose from oat-spelt xylan. In the presence of all three purified enzymes the hydrolysis products of oat-spelt xylan were mainly xylose, arabinose and substituted xylotetrose with lesser amount of substituted xylotriose. Conclusions: The addition of the b-xylosidase and a-L L-arabinofuranosidase enzymes to purified xylanases more than doubled the degradation of xylan from 28 to 58% of the total substrate with xylose and arabinose being the major sugars produced. Significance and Impact of the Study: The results highlight the role of xylan de-branching enzymes in the degradation of xylan and suggest that the use of enzyme cocktails may significantly improve the hydrolysis of xylan in industrial processes.