Regulation of the production of hemicellulolytic and cellulolytic enzymes by a Streptomyces sp. growing on lignocellulose.
A Streptomyces sp. isolated from compost degraded the hemicellulose fraction of straw efficiently but apparently not native cellulose. Ball-milled straw induced endoglucanase, beta-glucosidase, beta-xylanase and beta-xylosidase. Carboxymethylcellulose, cellotetraose and cellotriose induced cellulolytic enzymes specifically whereas cellobiose acted as inducer for beta-glucosidase only. Cellotriose and cellotetraose induced beta-glucosidase, but only partially induced endoglucanase. Hemicellulose (in the form of xylan) and xylobiose induced only beta-xylanase and beta-xylosidase. Kraft lignin and syringic acid induced beta-xylanase and endoglucanase but not the other enzymes. 3,4-Dimethoxycinnamic acid slightly induced beta-xylanase whereas 3,5-dimethoxy-4-hydroxycinnamic acid specifically induced endoglucanase. Neither veratric acid nor vanillic and ferulic acids induced any of the cellulolytic or hemicellulolytic enzymes. Enzyme production was subject to a form of carbon catabolite repression. Endoglucanase and beta-xylanase were excreted into the culture medium. Four protein components, one acidic (pI 5.2) and three basic (pI 8.15, 8.45 and 8.65) exhibited beta-xylanase activity. Two acidic components (pI 3.55 and 3.75) displayed endoglucanase activity.
Godden
B
B
Laboratoire de Microbiologie, Faculté des Sciences, Université Libre de Bruxelles, Belgium.
Legon
T
T
Helvenstein
P
P
Penninckx
M
M
D002480:Cellulase / Q000096:biosynthesis; D002482:Cellulose / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases; D004790:Enzyme Induction; D005990:Glycerol / Q000494:pharmacology; D008031:Lignin / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology*; D014995:Xylosidases / Q000096:biosynthesis; D001617:beta-Glucosidase / Q000096:biosynthesis
C036909:lignocellulose; D002482:Cellulose; D008031:Lignin; D014995:Xylosidases; D001617:beta-Glucosidase; C026579:exo-1,4-beta-D-xylosidase; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases; D005990:Glycerol