These copolymers are produced by the controlled fermentation of Alcaligenes eutrophus using mixtures of glucose and propanoic acid as carbon sources. The organism used has not been genetically engineered and has been derived from a single wild-type organism Alcaligenes eutrophus strain H16 NCIMB 10442. Master stocks of the organism are stored as freeze-dried ampoules. A submaster/working stock is prepared from the master stock and stored in liquid nitrogen and used to prepare inocula for the fermenter. Fermenter samples will be examined daily both microscopically and for any changes in colonial morphology on a variety of agars at different temperatures. The copolymers are isolated from heat treatment bacteria by controlled digestion of the other cellular components, washing and drying. These copolymers are normally offered as formulated, melt formed granules containing additives such as nucleating agents, plasticisers, fillers, stabilisers and pigments which all conform to the general and individual specifications.
where n/(m+n) greater than 0 and less or equal to 0.25
Average molecular weight
Not less than 150,000 Daltons (measured by gel permeation chromatography).
Assay
Not less than 98% poly (3-D- hydroxybutanoato-co-3-D-hydroxypentanoate) analysed after hydrolysis as a mixture of 3-D-hydroxybutanoic and 3-D-hydroxypentanoic acids.
Description
White to off-white powder after isolation.
Characteristics
Identification tests:
Solubility
Soluble in chlorinated hydrocarbons such as chloroform or dichloromethane but practically insoluble in ethanol, aliphatic alkanes and water.
Migration
The migration of crotonic acid should not exceed 0.05 mg/kg food.
Purity
Prior to granulation the raw material copolymer powder must contain:
– Nitrogen
Not more than 2,500 mg/kg of plastic
– Zinc
Not more than 100 mg/kg of plastic
– Copper
Not more than 5 mg/kg of plastic
– Lead
Not more than 2 mg/kg of plastic
– Arsenic
Not more than 1 mg/kg of plastic
– Chromium
Not more than 1 mg/kg of plastic
2
23547
POLYDIMETHYLSILOXANE (MW>6800)
Minimum viscosity 100 centistokes at 25°C
3
25385
TRIALLYLAMINE
40 mg/kg hydrogel at a ratio of 1 kg food to a maximum of 1.5 grams of hydrogel. For use only in hydrogels intended for non-direct food contact use.