Breeding,Screening And Function Of Two Microbiota Active In Kelp Degradation

Kelp is a kind of economic seaweed which is farmed in China at a large scale. In addition to known as normal seafood, kelp also has the potential in many industrial fields such as food process, medicine, agriculture and energy, which is all attributed to the abundant polysaccharides contained in kelp. Kelp polysaccharides, such as alginate, fucoidan and laminaran, have many pharmacological activities, and besides, are all fermentable. In this paper, kelp was used as the sole substrate to breed certain microbita which can degrade this alga. Two communitis, named R1 and HZ, were respectively breeded from freshwater and seaweed.70 bacterial strains were isolated from R1 and 29 ones were from HZ. Phylogenetic analysis and screening of functional enzymes were both practiced on each stain. Based on the diversity of these strains, two man-formed microbiota, named R1-3-A1 which was composed of 3 strains and HZ-3-A which was composed of 2 strains, were constructed. According to the observation of kelp remains and the measurement of enzyme activity, as well as the total and the reducing sugar test, the two composite bacteria were proved to be active in digesting polysaccharides and fluidifying alga.Furthermore, a alginate lyase producing strain, named HZ-22, was picked out for further research. Phylogenetic analysis showed that HZ-22 belonged to genus Tamlana and shared the highest sequence similarity of 96.834%with Tamlana agarivorans JW-26T. Based on the morphological and physiological characterizations, it is proposed that HZ-22 should represent a novel species of genus Tamlana. The enzymatic properties of the crude alginate lyase were tested. The optimal catalyzing conditions were 40-50℃and pH 7.0-8.0. Besides, this enzyme could remain activty at high NaCl concentration up to 0.8M, which showed a prominent salt tolerance. By now, no other Tamlana strains have been reported to produce alginate lyase yet. Thus, the alginate lyase produced by HZ-22 has potential in the industrial degradation of alginate.