Enhanced production of (1 → 3)-β-d-glucan by a mutant strain of Agrobacterium species

Optimization, Purification and Physicochemical Characterization of Curdlan Produced by Paenibacillus sp. Strain NBR-10

“…NBR-10 revealed six main resonances at 103.51, 73.35, 86.68, 68.88, 76.81 and 61.34 ppm, which are designed as C-1, C-2, C-3, C-4, C-5 and C-6 respectively, representing beta (1,3)-D-glucan backbone in the produced curdlan. The same result for the 13 C NMR spectrum of curdlan has been previously reported 6 . All of the above results supported that the polymer produced by Paenibacillus sp.NBR-10 was actually curdlan.…”

“…Ten grams of the air dried samples were added to 100 ml of sterile saline solution and agitated at 100 rpm for 10 min; 0.1 ml of the supernatant was transferred to 0.9 ml of sterile saline and serial dilutions (10 -1 to 10 -6 ) were prepared. 100 µl of each dilution was added and distributed on specific media containing aniline blue and Congo red dyes 13 , the medium was consisted of (g/l): sucrose (20.0), yeast extract (5.0), dye (0.05) and agar (20.0) at pH 7.0. Inoculated plates were incubated for 48 h at 35 o C, colonies showing intense blue or red color were streak purified at least three times on the same agar medium and kept at 4 o C for further studies.…”

“…Kim et al 13 and Nakanishi et al 16 reported that, curdlan bind with Congo red forming a red complex and bind with aniline blue forming a blue complex, but aniline blue is more specific to curdlan more than Congo red, the rate of color complex formation was dependent on the polymer concentration.…”

“…Similar results obtained by Wang 28 in identification of the purified curdlan from Agrobacterium sp. 13 C NMR spectra (Figure 4) of polysaccharide produced by Paenibacillus sp. NBR-10 revealed six main resonances at 103.51, 73.35, 86.68, 68.88, 76.81 and 61.34 ppm, which are designed as C-1, C-2, C-3, C-4, C-5 and C-6 respectively, representing beta (1,3)-D-glucan backbone in the produced curdlan.…”

β-Glucans and Probiotics

“…For example, the chemical structure of β-glucans isolated from bacteria is a simple linear β(1,3)-D-glycopyranosyl polymer with none, or sometimes limited, β(1,3)-and β(1,2)-D-glycopyranosyl branch chains (Lam and Cheung, 2013). Members of the Agrobacterium genera, produce linear β-glucans, commonly known as Curdlan, which can contain up to 12,000 glucose units and is biosynthesized during the post-stationary growth phase (Futatsuyama et al, 1999;Kim et al, 2003). However, also cyclic β(1,3)-and β(1,6)-D-glycopyranosyl linked glucans have been isolated from bacteria, e.g., from several plant-symbiotic bacterial species including Bradyrhizobium japonicum and Rhizobium loti, in which the cyclic structure seems to play a role in their symbiotic association with plant, helping the nodulation forming (Gay-Fraret et al, 2012).…”