Alginate-deriving oligosaccharide production by alginase from newly isolatedFlavobacteriumsp. LXA and its potential application in protection against pathogens

Abstract

Aims: To examine algino‐oligosaccharide production by alginase from newly isolated Flavobacterium sp. LXA and its elicitor and antibacterial activity. Methods and Results: Algino‐oligosaccharide production from alginate was carried out using alginase obtained from a newly isolated Flavobacterium sp. LXA. When alginase was partially purified by dual ammonium sulfate precipitation and used for alginate degradation, the viscosity loss correlated well with the release of reducing terminals. The optimal temperature and pH for alginate degradation was 40°C and pH 7·0, respectively. When alginate was added at an initial concentration of more than 0·8%, the maximal degradation rate of alginate was obtained. Under these optimal reaction conditions and with partially purified alginase, the average degrees of polymerization (DP) of alginate‐degraded products was about 6·0, which favoured algino‐oligosaccharide production. The algino‐oligosaccharides showed an elicitor activity stimulating the accumulation of phytoalexin and inducing phenylalanine ammonia lyase in soybean cotyledon, and antimicrobial activity on Pseudomonas aeruginosa. Conclusions: Algino‐oligosaccharide could be degraded from alginate by the partially purified alginase and its maximal bioactivity occurred on the oligosaccharide with average DP 6·8. Significance and Impact of the Study: Algino‐oligosaccharide was first reported to have elicitor and antibacterial activity and have potential as a biological agent for protection against plant or human disease.

Alginate lyase: Review of major sources and classification, properties, structure-function analysis and applications

“…[8][9][10][11][12][13][14] Oligomeric alginates obtained from lyase degradation of alginate act as oligosaccharines and regulate physiological processes in plants and microorganisms, such as promoting the growth of Bifidobacterium spp., enhancing the germination and shoot elongation in plants. The oligosaccharides exhibit many physiological activities, such as antitumor, stimulating production of cytokines, regulating the blood lipids and sugars.…”

“…[5][6][7] They can be used as growth promoters for plants and therapeutic agents such as anticoagulants and tumor inhibitors. [8][9][10] They can also induce the cytokine production and regulate the blood sugar as well as lipid. 11,12 Due to the high-efficiency and high-specificity, alginate lyases for mild degradation have been the focus for various fields.…”

Optimization of Production and Preliminary Characterization of New Exopolysaccharides from <i>Gluconacetobacter hansenii</i> LMG1524

“…Gluconacetobacter hansenii PJK is known to produce glucuronic acid oligomers [4,5] which, due to the structures similarities with alginate oligomers, are expected to have at least eliciting activities [6,7]. Moreover G. hansenii was formerly named Acetobacter hansenii by Gosselé [8] and the genus Acetobacter contains species which produce other water-soluble heteropolysaccharides.…”

Elicitor activity of algino-oligosaccharide and its potential application in protection of rice plant (Oryza salivaL.) againstMagnaporthe grisea

“…LXA, was isolated from rotting algae in our laboratory and was found to produce alginate lyase in the culture supernatant. [14,15] The alginate degradation products with an unsaturated urinate terminal showed elicitor activity by stimulating the accumulation of phytoalexin and inducing PAL activity in soybean cotyledons, [13] suggesting a potential protection of plants against phytopathogens. In this study, the algino-oligosaccharides produced by alginate lyase were applied on rice plants.…”

“…[12] Therefore, the production of various alginate oligosaccharides using lyase is sought for the development of a more functional alginate for future industrial application. [13] An alginate-degrading bacterium, Flavobacterium sp. LXA, was isolated from rotting algae in our laboratory and was found to produce alginate lyase in the culture supernatant.…”