Polyhydroxybutyrate (PHB) is a polyhydroxyalkanoate (PHA), a polymer belonging to the polyesters class.
- Bacteria first used to make PHB in 1925 at Pastuer Institute in Paris. - In 1970’s adopted by Imperial Chemical Industries (ICI) – Alcaligenes Eutrophus grown in fermentation vats with Molasses - The bacteria is then starved of nutrients (glucose and nitrogen) – PHB is produced as an energy store for the bacteria. - In 1980’s Maddison University (Virgina) successfully cloned the 3 genes of A. Eutrophus that control PHB production and transferred them to Escherichia coli – an easier bacteria to work with allowing easier manipulation of the polymer depended on the need. - In 1990’s the 3 genes were cloned into sugar beets and turnips – much larger scale production of polymer. Work continuing (with Monsanto – company bought patent) into cloning genes to corn.
The manufacturing process of PHB begins with sunlight. Through photosynthesis carbon dioxide from the atmosphere is converted to carbohydrates via sugar beets or sugar cane. These carbohydrates (like Lactose, Fructose and Glucose) are the raw material for the manufacturing of PHB.
•In medicine, PHB is compatible with the blood and tissues of mammals. The monomer of PHB is a normal metabolic in the human blood. As the body reabsorbs PHB it might be used as a surgical implant, in surgery, as seam threads for the healing of wounds and blood vessels. •In pharmacology, PHB can be used as microcapsules in therapy or as materials for cell and tablet packaging. •In packaging for deep drawing articles in the food industry, for example, bottles, laminated foils, fishnets, potted flower, hygiene, fast food, one-way cups, agricultural foils and fibres in textile.
Advantages of PHB:
•Good mechanical properties, especially when low density and price are taken into account. •Recyclable, renewable and non-abrasive to manufacturing...