Isolation and purification of carrageenase enzyme from Pseudoalteromonas carrageenova IFO 12985 (Protobacterium)

Bernadette M. Henares
Fabian M. Dayrit, Ateneo de Manila University
Nina Rosario L. Rojas, Ateneo de Manila University


Carrageenan is a gel-forming polysaccharide extracted from the cell wall of red seaweeds. One of the most common forms of this sulfated galactan is the t-carrageenan that is biodegraded by an anzyme called t-carrageenase. This extracellular enzyme specifically cleaves the alpha-1, 4 linkage between the D-galactopyranosyl-4-sulfate and 3,6- anhydro-alpha -D-galactopyranosyl-2-sulfate residues. Several studies have been conducted on the isolation, purification and characterization of t-carrageenase from various marine bacteria such as Zobella galactanovorans and Alteromonas fortis. Here, the authors report on the isolation, purification and partial characterization of t-carrageenase present in Pseudoalteromonas carrageenovora. From the cell-free supernatant of cultures grown on t-carrageenan, t-carrageenase was purified by ammonium sulfate precipitation and followed by ion-exchange chromatography on CM and DEAE. The isolated enzyme had a molecular weight of about 55 kDa as estimated by SDS-PAGE, in agreement with the reported MW for t-carrageenase. Hydrolytic activity was observed towards t-carrageenan and not against t-carrageenan when analyzed by the reducing sugar assay. Analysis of the unfractionated hydrolysate by sup13C NMR also confirmed that degradation had taken place.