Photocatalytic and Antibacterial Studies on Poly(Hydroxybutyrate-co-Hydroxyhexanoate) / Titanium Dioxide Composites

Bacteria and viruses causes food poisoning outbreaks. To prevent this, antimicrobial films can be used as packaging material or coatings on food processing surfaces. Titanium dioxide (TiO2) irradiated with ultraviolet light produces free radicals that can destroy organic contaminants and bacteria. U.S. Food and Drug Administration and the U.S. Pharmacopeia approves TiO2 as a colorant. Polyhydroxybutyrate is a bio-based polymer. Blends of this polymer are being studied for implants and drug delivery. TiO2 immobilized to blends of this polymer may be suitable in food processing. Poly(hydroxybutyrate-co-hydroxyhexanoate) and titanium oxide (PHB-HH/TiO2) composite films were irradiated under fluorescent and blacklight lamps. The results show that they can be activated by both lamps. However, the photocatalytic activity is higher in blacklight. The films were irradiated in the presence of Escherichia coli and Staphylococcus aureus. Both had a 0 log count when a 3% PHB-HH/TiO2 composite film was exposed to blacklight for 5 h. Exposure to fluorescent light showed some antibacterial activity. The photocatalytic activity of the films was enough to inhibit bacterial growth when exposed to fluorescent lamps. PHB-HH/TiO2 composite films have photocatalytic and antibacterial properties when exposed to fluorescent and blacklight lamps. The films can be used in the food industry