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Characterization of cellulase and xylanase activities of Clostridium celerecrescens
Author(s) -
Palop M. Llanos,
Vallés Salvador,
Piñaga Francisco,
Flors Agustí
Publication year - 1991
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280510111
Subject(s) - xylanase , cellobiose , cellulase , xylan , cellulose , chemistry , xylose , food science , mesophile , bacteria , biochemistry , hydrolysis , substrate (aquarium) , enzyme , fermentation , biology , ecology , genetics
The production of cellulases and xylanase by Clostridium celerecrescens, a new anaerobic mesophilic cellulolytic bacterium, was studied using various substrates (cellobiose, xylan and cellulose Whatman CF‐11). While both cellulase (β‐1,4‐D‐glucan glucanohydrolase) and xylanase (β‐1,4‐xylan xylanohydrolase) were produced on cellulose, only the latter was produced when xylan was used as the sole carbon source. A weak p‐nitrophenyl‐β‐D cellobiohydrolase activity was detected in the extracellular filtrates when using cellulose as a substrate. Otherwise, β‐glucosidase (p‐nitrophenyl‐β‐D‐glucopyranosidase) was always found to be associated with the bacteria and reached its maximum levels of growth on cellobiose. In all cases, enzyme production showed a cell growth associated profile. Activities of these enzymes had their optimal values within the ranges of temperature and pH reported for the corresponding enzymes from similar anaerobic mesophilic microorganisms, although a relatively high optimum temperature, 55°C, was found for xylanase. All enzymes showed a 90% reduction of half‐life time for each 8°C increment of temperature. A 50% inhibition of xylanase and β‐cellobiohydrolase activity was observed, through a competitive mechanism, by xylose (0.677 mmol dm −3 ) and cellobiose (28 mmol dm −3 ) respectively.