화학공학소재연구정보센터
Applied Microbiology and Biotechnology, Vol.41, No.3, 366-372, 1994
Production of Extracellular Enzymes During the Solubilization of Straw by Thermomonospora-Fusca Bd25
The production of three extracellular enzymes during the solubilisation of ball-milled wheat straw by seven actinomycete strains, was examined. A general correlation was observed between the production of extracellular enzymes (xylanases, endoglucanases and peroxidases) and the formation of the solubilised lignocellulose intermediate product (APPL), with the thermophilic actinomycete Thermomonospora fusca BD25 exhibiting greatest extracellular enzyme activity and highest APPL production. Production of all three enzymes; endoxylanase, endoglucanase and peroxidase, and lignocellulose solubilisation, occurred during primary growth with maximum activity at the end of the exponential phase (48-96 h). The inducibility and stability of extracellular enzymes from T.fusca were further characterised. When xylan replaced ball-milled wheat straw as the growth substrate, reduced enzyme activities were observed (28-96% reduction in enzyme activities), whereas carboxymethylcellulose was found to be a poor inducer of all three enzyme activities (80-100% reduction in enzyme activities). The pH and temperature optima for extracellular enzyme activities from T. fusca was found to be pH 7.0-8.0 and 60 degrees C, respectively. Analysis of concentrated crude supernatant from T. fusca by native polyacrylamide gel electrophoresis revealed the existence of two non-haem peroxidases. The stability of the extracellular lignocellulose-degrading enzymes for T.fusca suggest their suitability for future biotechnological processes such as biobleaching.