PRODUCTION OF A HIGH-ACTIVITY OF AN EXTREMELY THERMOSTABLE BETA-MANNANASE BY THE THERMOPHILIC EUBACTERIUM RHODOTHERMUS-MARINUS, GROWN ON LOCUST BEAN GUM
J. Gomes et W. Steiner, PRODUCTION OF A HIGH-ACTIVITY OF AN EXTREMELY THERMOSTABLE BETA-MANNANASE BY THE THERMOPHILIC EUBACTERIUM RHODOTHERMUS-MARINUS, GROWN ON LOCUST BEAN GUM, Biotechnology letters, 20(8), 1998, pp. 729-733
The production of a highly thermostable mannanase by Rhodothermus mari
nus was increased 16.5-fold by optimising the concentrations of locust
bean gum and yeast extract using central composite designs. The optim
ised medium and culture conditions yielded mannanase activity at 495 n
kat ml(-1) (248 nkat mg(-1) protein). In addition, alpha-L-arabinofura
nosidase, beta-xylanase, beta-xylosidase, beta-glucosidase, beta-manno
sidase, alpha-galactosidase, beta-galactosidase and endoglucanase acti
vities were detected at 32 nkat ml(-1), 30 nkat ml(-1), 16 nkat ml(-1)
, 15 nkat ml(-1), 0.1 nkat ml(-1), 1 nkat ml(-1), 0.5 nkat ml(-1) and
8 nkat ml(-1), respectively. No filter paper cellulase activity could
be detected. The optimum pH of the mannanase was 5.0-6.5 and it showed
high stability from pH 5 to 10 after 16 h incubation at 50 degrees C.
The enzyme activity was maximum at 85 degrees C, with half lives of 4
5.3 h at 85 degrees C and 4.2 h at 90 degrees C. This is the first rep
ort on the production of such a high activity of extremely thermostabl
e mannanase by an extreme thermophilic bacterium.