Bacterial Cellulose Production from Industrial Waste and by-Product Streams.

The utilization of fermentation media derived from waste and by-product streams from biodiesel and confectionery industries could lead to highly efficient production of bacterial cellulose. Batch fermentations with the bacterial strain Komagataeibacter sucrofermentans DSM (Deutsche Sammlung von Mikroorganismen) 15973 were initially carried out in synthetic media using commercial sugars and crude glycerol. The highest bacterial cellulose concentration was achieved when crude glycerol (3.2 g/L) and commercial sucrose (4.9 g/L) were used. The combination of crude glycerol and sunflower meal hydrolysates as the sole fermentation media resulted in bacterial cellulose production of 13.3 g/L. Similar results (13 g/L) were obtained when flour-rich hydrolysates produced from confectionery industry waste streams were used. The properties of bacterial celluloses developed when different fermentation media were used showed water holding capacities of 102-138 g · water/g · dry bacterial cellulose, viscosities of 4.7-9.3 dL/g, degree of polymerization of 1889.1-2672.8, stress at break of 72.3-139.5 MPa and Young's modulus of 0.97-1.64 GPa. This study demonstrated that by-product streams from the biodiesel industry and waste streams from confectionery industries could be used as the sole sources of nutrients for the production of bacterial cellulose with similar properties as those produced with commercial sources of nutrients.

Effect of the conditions of platinum deposition on titania nanocrystalline films on the efficiency of photocatalytic oxidation of ethanol and production of hydrogen.

Titania nanocrystalline films have been deposited on glass slides and loaded with Pt nanoparticles by adsorption from aqueous solutions of sodium tetrachloroplatinate followed by UVA radiation or heat treatment. These metal/semiconductor combined photocatalysts have been used for photooxidation of aqueous ethanol and production of hydrogen. The efficiency of the photocatalytic process was associated with the metal load on the titania films and the size of the metal nanoparticles. Characterization of the combined photocatalyst has been made by X-ray photoelectron spectroscopy and transmission electron microscopy.