Activity and partial characterisation of xylanolytic enzymes in the earthworm Eisenia andrei fed on organic wastes

This study demonstrates the occurrence of active xylanolytic enzymes in ext racts from Eisenia andrei, Bouche 1972. Xylanase was the most active enzyme (2.06 U g(-1)), followed by acetyl xylan esterase (0.55 U g(-1)). Lower ac tivities showed beta-D-glucuronidase (0.17 U g(-1)), alpha-L-arabinosidase (0.04 U g(-1)) and beta-xylosidase (0.03 U g(-1)). All of the xylanolytic e nzymes displayed higher total activity when the earthworms were fed on a xy lan-containing medium. Xylanase, alpha-L-arabinosidase and acetyl xylan est erase showed maximal activity at neutral pH. In contrast, beta-xylosidase a nd beta-glucuronidase displayed maximal activity at pH 3.0 and 4.0, respect ively. All enzymes displayed a high activity within the physiological tempe rature range 35 to 40 degrees C. K-m and V-max values of xylanolytic enzyme s were also estimated. Kinetic parameters for xylanase were determined in e xtracts of earthworms fed on standard medium (K-m = 6.91 +/- 1.120 mg ml(-1 ); V-max = 0.05 +/- 0.002 U mg(-1)), and in extracts of earthworms fed on a medium containing xylan (K-m,=5.60 +/- 1.070 mg ml(-1); V-max=0.12 +/- 0.0 06 U mg(-1)). (C) 1999 Elsevier Science Ltd. All rights reserved.