Investigation Of Carrageenase From Marine Bacterium Cellulophaga Sp. QY201

Carrageenans are gel-forming hydrocolloids extracted from the cell walls of marine red algae, such as Eucheuma, Chondrus, Gigartina, Hypnea. These polysaccharides consist of a basic repeating structure of alternating 3-linked β-D-galactopyranosyl and 4-linked α-D-galactopyranosyl units. At present, the three main commercial carrageenans are the κ-, ι- and λ- carrageenan. Carrageenans have been widely used as raw materials in food, textile, agriculture, petrochemical industry and so on. Recently, some carrageenans-oligosaccharides are continually found to be of valuable pharmacological activities in the development of drugs. Carrageenans-oligosaccharides are traditionally prepared by the chemical hydrolysis. However, this degradation method is so severe that the hydrolysis products of the polysaccharide cannot maintain homogenous. Enzymatic degradation of polysaccharide may be a promising alternative, because of the product specificity and the mild conditions during enzymatic degradation. Currently, although κ-carrageenanase has been widely studied, there are a few reports on ι- and λ-carrageenanases. Therefore, the discovery of new ι- and λ-carrageenanases with high activity and high product specificity are useful for the preparation of carrageenans-oligosaccharides, which surely show a wide range of applications.In the present study, 298 carrageenanase-producing marine bacterium strains had been screened from coastal waters of Qingdao with mediums containing ι-carrageenan as the sole carbon and energy source. One strain, QY201, had the highest enzyme activity and could produce κ-, ι- and λ-carrageenanases. So, strain QY201 was selected in the following experiments.Strain QY201 was Gram-negative and motile. The colony colours of the strain QY201 was yellow and the colony morphology of the strain was round, smooth and...