Intracellular Alginolytic Enzymes of the Marine Bacterium Pseudoalteromonas citrea KMM 3297

Abstract

The marine bacterium Pseudoalteromonas citrea KMM 3297 is an associate of the holothurian Apostichopus japonicus. When grown in a medium containing glucose, the strain produces two intracellular alginolytic enzymes, AlI and AlII. Fucoidan from the brown alga Fucus evanescens induces synthesis of one more alginolytic enzyme, AlIII. These enzymes were separated using anion-exchange chromatography. The alginate lyase AlI completely retains its activity at 35 degrees C, AlII and AlIII being stable at 45 degrees C. The alginate lyases exhibit maximal activities in the range of pH 7-8. The molecular weights of AlI, AlII, and AlIII determined by gel filtration are 25, 79, and 61 kD, respectively. All the investigated enzymes are endo-type alginate lyases. They catalyze degradation of polyguluronate (poly-G) and polymannuronate (poly-M) yielding oligosaccharides of the polymerization degree of 5 > or = n > or = 3 with the unsaturated bond between the C4 and C5 atoms of the non-reducing terminus. A mixture of these three enzymes exhibits synergism while acting on the polymeric substrate. The Km values of the alginate lyase AlI for poly-G and poly-M are 24 and 34 micro g/ml, respectively. Alginate lyase AlIII exhibits less affinity to poly-M (Km = 130.0 microg/ml) than to poly-G (Km = 40.0 microg/ml). NaCl (0.2 M), MgCl2 and MgSO4 (0.01 M) activate all three enzymes more than twofold. The presence of several alginolytic enzymes of different specificity provides efficient destruction of alginic acids of brown algae by the strain P. citrea KMM 3297.

Optimization of culturing condition and medium composition for the production of alginate lyase by a marine Vibrio sp. YKW-34

“…dium containing Laminaria powder did not show positive effect. The result was different from that described by Alekseeva et al (2004), in which the addition of fucoidan had positive effect on alginate lyase production. However, the addition of glucose to Laminaria powder decreased alginate lyase production by almost 10-folds.…”

“…However, the addition of glucose to Laminaria powder decreased alginate lyase production by almost 10-folds. This result was consistent with that of Alekseeva et al (2004). Horn and Østgaard (2001) suggested that the substrate which supports the fastest growth will be utilized first and the synthesis of the enzyme utilizing the second substrate will be inhibited.…”

Microbial Communities Associated with Holothurians: Presence of Unique Bacteria in the Coelomic Fluid

“…In addition, Echinodermata immunocytes produce reactive oxygen species (ROS) when in contact with bacteria or bacterial cell wall proteins (28). Nevertheless, potentially pathogenic microbes and fungi were repeatedly isolated from the holothurian coelomic fluid (1, 46). In addition, the coelomic fluids of oysters and abalones were used as inocula for isolating novel microorganisms (10, 24, 52).…”

“…Although some microbes, e.g. , members of the genera Pseudoalteromonas and Salegentibacter , have been isolated in pure cultures from holothurians (1, 23, 34, 48), little is known about the associated microbial diversity.…”

Cloning, expression, and characterization of a new pH‐ and heat‐stable alginate lyase from Pseudoalteromonas carrageenovora ASY5

“…Strain No. 1786 (Chaki, Baba, Hiura, & Kobayashi, ), Pseudoalteromonas elyakovii IAM 14594 (Sawabe, Takahashi, Ezura, & Gacesa, ), and Pseudoalteromonas citrea KMM 3297 (Alekseeva et al, ) have polyM and polyG substrate specificity. This property allows them to hydrolyze alginate to produce alginate oligosaccharides efficiently.…”