Production and characterization of guluronate lyase from Klebsiella pneumoniae for applications in seaweed biotechnology.

Cultures of Klebsiella pneumoniae fermenting sodium alginate produce an extracellular guluronate-specific alginate lyase. This enzyme production was studied in stirred-tank fermentors. Different alginate substrates gave moderate differences in growth and enzyme yield. Alginates with low guluronic content gave reduced biomass but favored enzyme production. Low molecular weight (down to DPn approximately 270) also favored enzyme production. Excessive depolymerization of substrates occurred during heat sterilization of culture media. The enzyme was characterized by its specificity and sensitivity to pH, salt, and calcium. Improved yields of viable protoplasts were documented for Laminaria digitata (Huds.) Lamour.