A Novel Polysaccharide Involved in the Pellicle Formation of Acetobacter aceti

Abstract

Acetobacter aceti IFO 3284 has been shown to have two types of strains: one forms a smooth-surfaced colony (S strain) and the other forms a rough-surfaced colony (R strain) (Matsushita et al., 1992). In this study, both S and R strains were isolated and characterized. The S strain grew well in submerged culture but very poorly in static culture. In contrast, the R strain grew well in static culture by floating on the surface of the culture medium, as well as in shaking submerged culture. Scanning electron microscopy revealed that the R strain was covered by some amorphous materials that were not seen in the S strain. The R strain produced 5-fold higher levels of sugars related to polysaccharides responsible for pellicle formation than the S strain did. Unlike cellulose of Acetobacter xylinum, the polysaccharides of the R strain were cellulase-resistant and alkaline-sensitive. The polysaccharides were not secreted into the culture medium, and more than 90% of them were retained in the membrane fraction when the cells were disrupted under mild conditions by lysozyme treatment. Furthermore, the polysaccharides were shown to be mainly attached to the outer membrane when separated. After solubilization with beta-octylglucoside, the membrane-attached polysaccharides were purified by several steps including enzyme treatment, column chromatography and alcohol precipitation. The purified polysaccharide was estimated to have an apparent molecular mass of 700-kDa based on Sephacryl S-500 column chromatography, and to be composed of two monosaccharides, glucose and rhamnose, at an approximately equimolar ratio. Thus, in this study, we clarified that the A. aceti R strain produced a polysaccharide associated with the flotation of the cells on the medium surface, like A. xylinum, and that the polysaccharide was a novel one consisting of glucose and rhamnose.

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

“…Moreover G. hansenii was formerly named Acetobacter hansenii by Gosselé [8] and the genus Acetobacter contains species which produce other water-soluble heteropolysaccharides. For example A. xylinum secretes "acetan", a polysaccharide containing glucose, mannose, glucuronic acid and rhamnose [9], whereas Acetobacter IFR101 produces a polysaccharide constituted of mannose, galactose and glucose [10] and other species producing similar EPS [11][12][13]. The acetan has a similar structure to xanthan [9] which is commercialized by several firms for food or non food applications, its controlled degradation might lead to oligosaccharides with bioactive properties [14].…”

Acetic Acid Fermentation ofAcetobacter pasteurianus: Relationship between Acetic Acid Resistance and Pellicle Polysaccharide Formation

“…2B, the sugar contents of the cells increased from the early EO phase to the AR phase, and finally decreased again in the AO phase. Since the sugar contents of cells have been found to be related to the polysaccharide attached to the cells, which could be detected only in the R strain, as described, 14,15) the culture appeared to be rich in cells having pellicle polysaccharides in the late EO phase to the AR phase. This might be related to the acetic acid resistance of the cells.…”

“…The difference in sugar contents between the R and S strains appeared to reflect the content of pellicle polysaccharides, since the sugar content detected in the S strain must have been due to other components such as lipopolysaccharides, not to the pellicle. 15) Thus, all the R strains of these Acetobacter species appeared to produce pellicle polysaccharides.…”

“…Although the staining principle is not clear, we think that the amorphous materials might be related to pellicles that have been found to be produced at the cell surface as capsular polysaccharides in Acetobacter species. 15,16) Acetic acid fermentation and pellicle polysaccharide production of thermotolerant A. pasteurianus SKU1108 in ethanol culture…”

“…plantarum JCM1149 are more resistant to acetic acid and ethanol than planktonic cells. 14) Acetobacter species, Acetobacter tropicalis SKU1100 and Acetobacter aceti IFO3284, have been shown to produce capsular polysaccharides as a pellicle or biofilm, 15,16) and have two different types of cells, the R (rough colony) and S (smooth colony) strains, where the R strain but not the S strain produces the pellicle. 17,18) Thus, pellicle formation migh also be a defense mechanism for acetic acid resistance, though this has never been confirmed.…”