Optimization of Culture Conditions for the Production of Extracellular Agarases from Newly Isolated Pseudomonas Aeruginosa AG LSL-11

An agar-degrading bacterium capable of utilizing agar as sole source of carbon and energy was isolated from sea water by enrichment culture technique. The bacterium was identified as Pseudomonas aeruginosa and the culture conditions were standardized for the maximal production of extracellular agarases. The bacterium grew in the pH range 5.0–11.0, optimal between pH 7.0 and 8.0; temperature between 25 °C and 37 °C, optimal at 30 °C and sodium chloride concentration 0–8% and optimal at 2% respectively. The agarases secreted by Pseudomonas aeruginosa AG LSL-11 were inducible by agar and not by any other simple sugars tested. Maximal agarase production was observed at pH 8.0, and temperature 30 °C. The bacterium had no requirement for NaCl for both growth and production of agarases. The bacterium did not utilize other polysaccharides like ĸ-carrageenan, alginate, cellulose and CMC. The activity staining of partially purified agarase preparation after native-PAGE revealed the presence of three different agarases, agarase LSL-11a, LSL-11b and LSL-11c, whose molecular weights were estimated to be 76, 64 and 46 kDa respectively.