Purification and Characterization of κ-carrageenase from a novel γ-proteobacterium, Pseudomonas elongata (MTCC 5261) syn. Microbulbifer elon comb. nov

The phenotypic and carrageenolytic features of a novel halo tolerant marine bacterium, isolated from decayed red algal samples collected along the west coast of India were studied. This gram-negative strain was identified as Pseudomonas elongata (MTCC 5261) syn. Microbulbifer elongatus comb. nov according to its morphological, physiological and molecular characterization. The extracellular kappa-carrageenase was purified 106.54-fold by a combination of ammonium sulfate precipitation (40 similar to-60%) and successive gel filtration chromatography. The purified protein fraction yielded significantly high activity of 426.19 units/mg protein and migrated as a single band on a sodium dodecyl sulfate polyacrylamide gel electrophoresis with a molecular weight of similar to 128 kDa. For kappa-carrageenase activity, optimum temperature was 40 degrees C whereas two pH optima i.e. 5.6 and 7.7 were observed. For kappa-carrageenan, the enzyme gave a K-m value of 6.66 mg/mL and a V-max value of 4 mu mol/min/mg when the reaction was carried out at 40 degrees C and pH 5.6. Isolated kappa-carrageenase could successfully generate protoplasts of Kappaphycus alvarezii. This is the first report on the production of kappa-carrageenase by this bacterium isolated from west coast of India. Molecular mass and various characteristics showed that the carrageenase from P. elongata was much different from those previously reported. (C) KSBB.