Bacterial cellulose pellicles were produced by Gluconacetobacter xylinus using non conventional low-cost carbon sources, such as glycerol remaining from biodiesel production and grape bagasse, a residue of wine production. The carbon sources assayed showed their suitability for microbial cellulose production, with relatively high production values such as 10.0 g/l for the culture medium with glycerol from biodiesel as carbon source and corn steep liquor as nitrogen source; and 8.0 g/l for the culture medium containing grape bagasse and corn steep liquor. Glucose, commercial glycerol and cane molasses were also assayed as carbon souces for comparison. The bacterial celluloses produced were characterized by means of scanning electron microscopy, Xray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. Morphological analysis showed that bacterial cellulose microfibrils produced from the non-conventional media used were several micrometers long and had rectangular cross-sections with widths and thicknesses in the range of 35-70 nm and 13-24 nm, respectively. X-ray patterns showed crystallinity levels in the range of 74-79% (area method), whereas both X-ray patterns and infrared spectroscopy evidenced the presence of bands characteristic of Cellulose I polymorph. Thermal properties were similar to those found for the pellicle obtained from glucose. The study performed showed the suitability of using wine residues or glycerol remaining from increasing biodiesel production as cheap carbon sources for production of bacterial cellulose microfibrils, with similar characteristics as those obtained by use of more expensive carbon sources such as glucose or commercial glycerol. On the other hand, the low cost nitrogen sources used (corn steep liquor or diammonium phosphate) also contributed to the economy of the bioprocess.Fil: Vazquez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Foresti, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Cerrutti, Patricia. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Galvagno, Miguel Angel. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús (San Martin); Argentin

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The utilization of vanillin was studied as a natural antimicrobial in a combined technology for producing a shelf-stable strawberry purée. Mild heat treatment (blanching) was combined with addition of 3,000 ppm vanillin and 500 ppm ascorbic acid and adjustment of water activity (a w ) to 0.95 and pH to 3.0. This prevented growth of both native and inoculated flora for ≥60 days storage at room temperature.