title: Acetobacter cellulosic biofilms search for new modulators of cellulogenesis and native membrane treatments.
abstract: Since natural substances like pseudoxanthins exert a positive effect on the cellulogenic ability of Acetobacter xylinum when producing cellulosic pellicles suitable for skin burn therapy, new defined and complex modulators were sought. Ca2+ and Mg2+ (4 mM) were strongly stimulatory. Na+ had no effect and K+ was inhibitory. Ammonium dihydrogen phosphate (0.12 g/L) ensured the same nitrogen supply as the same concentration of yeast extract as measured by cellomembrane dry wt./yield albeit higher yeast extract supplies produced thicker membranes. Corn steep liquor (CSL) was also progressively beneficial from 0.125 to 0.5 mL/L, and this yield could be further improved by the combination of CSL with a tea infusion (source of caffeine). Uridine (precursor for UDP-Glc, sugar donor in cellulose biosynthesis), guanine, guanosine, and its butirylated derivatives (precursors for the positive modulator of cellulose synthetase, di-cGMP) resulted in only moderate stimulation. Sodium phytate and betaine were also slightly stimulatory. The fibrilar product from a new Acetobacter isolate (Ax-M) was characterized as cellulose by comparison with the solid-state(13)C-NMR of algal cellulose. Its X-ray diffractogram was a confirmatory analysis. After incorporation of tamarind xyloglucan to previously air-dried cellulosic pellicles, diffractometry displayed only slight differences. Mercerized (5M NaOH) fresh cellulosic biofilms underwent drastic size reduction (3.5-fold), turning compact nut still flexible if maintained wet.
authors.affiliation: LQBB-Biomass Chemo/Biotechnology Laboratory, Department of Biochemistry, UFPR (Federal University of Paraná), PO Box 19046 (81531-990) CURITIBA-PR-Brazil.
authors.forename: J D
authors.initials: JD
authors.lastname: Fontana
authors.forename: C G
authors.initials: CG
authors.lastname: Joerke
authors.forename: M
authors.initials: M
authors.lastname: Baron
authors.forename: M
authors.initials: M
authors.lastname: Maraschin
authors.forename: A G
authors.initials: AG
authors.lastname: Ferreira
authors.forename: I
authors.initials: I
authors.lastname: Torriani
authors.forename: A M
authors.initials: AM
authors.lastname: Souza
authors.forename: M B
authors.initials: MB
authors.lastname: Soares
authors.forename: M A
authors.initials: MA
authors.lastname: Fontana
authors.forename: M F
authors.initials: MF
authors.lastname: Guimaraes