Purification, characterization, immobilization and applications of an enzybiotic β-1,3-1,4-glucanase produced from halotolerant marine Halomonas meridiana ES021

Extracellular beta-1,3-1,4-glucanase-producing strain Halomonas meridiana ES021 was isolated from Gabal El-Zeit off shore, Red Sea, Egypt. The Extracellular enzyme was partially purified by precipitation with 75% acetone followed by anion exchange chromatography on DEAE-cellulose, where a single protein band was determined with molecular mass of approximately 72 kDa. The K-m value was 0.62 mg beta-1,3-1,4-glucan/mL and V-max value was 7936 U/mg protein. The maximum activity for the purified enzyme was observed at 40 degrees C, pH 5.0, and after 10 min of the reaction. beta-1,3-1,4-glucanase showed strong antibacterial effect against Bacillus subtilis, Streptococcus agalactiae and Vibrio damsela. It also showed antifungal effect against Penicillium sp. followed by Aspergillus niger. No toxicity was observed when tested on Artemia salina. Semi-purified beta-1,3-1,4-glucanase was noticed to be effective in clarification of different juices at different pH values and different time intervals. The maximum clarification yields were 51.61% and 66.67% on mango juicee at 40 degrees C and pH 5.3 for 2 and 4 h, respectively. To our knowledge, this is the first report of beta-1,3-1,4-glucanase enzyme from halotolerant Halomonas species. [GRAPHICS] .