Production of Poly-3-hydroxybutyrate-co-3-hydroxy-valerate with Alcaligenes latus DSM 1124 on Various Carbon Sources

Abstract

Polyhydroxyalkanoates are thermoplastic polyesters which are produced as storage compounds by a vast number of bacterial strains under growth limiting conditions. These polymers can be produced in different qualities with a wide range of physical properties, either as homo-polymer (Poly-3-hydroxybutyrate) or, with different co-substrates, as copolymers (e.g. Poly-3-hydroxybutyrate-co-3-hydroxyvalerate, Poly-3-hydroxybutyrateco-4-hydroxybutyrate). They are completely biodegradable and therefore an interesting alternative to the mineral-oil derived plastics as packaging materials. Nevertheless up to now PHAs have not been able to compete with the conventional plastics because their price is still much too high. One possible way to reduce the production costs is to use cheaper carbon sources like agricultural waste materials. The strain Alcaligenes latus DSM 1124 is able to accumulate high amounts of PHAs and therefore very interesting for a future production. The growth and the accumulation of PHAs on various carbon sources like glucose, glycerol and Na-valerate have been investigated in a labscale fermenter. PHA contents and kinetic data like the specific growth rate and yield coefficients were determined.