Polyhydroxyalkanoate (PHA) is a family of biopolymers produced by some bacteria and is accumulated
intracellularly as carbon and energy storage material. Fifteen PHA-producing bacterial strains were identified
from bacteria isolated from Antarctic soils collected around Casey Station (66◦17S, 110◦32E) and
Signy Island (60◦45S, 45◦36W). Screening for PHA production was carried out by incubating the isolates
in PHA production medium supplemented with 0.5% (w/v) sodium octanoate or glucose. 16S rRNA gene
sequence analysis revealed that the isolated PHA-producing strains were mainly Pseudomonas spp. and
a few were Janthinobacterium spp. All the isolated Pseudomonas strains were able to produce mediumchain-
length (mcl) PHA using fatty acids as carbon source, while some could also produce mcl-PHA by
using glucose. The Janthinobacterium strains could only utilize glucose to produce polyhydroxybutyrate
(PHB). A Pseudomonas isolate, UMAB-40, accumulated PHA up to 48% cell dry mass when utilizing fatty
acids as carbon source. This high accumulation occurred at between 5 ◦C and 20 ◦C, then decreased with
increasing temperatures. Highly unsaturated mcl-PHA was produced by UMAB-40 from glucose. Such
characteristics may be associated with the ability of UMAB-40 to survive in the cold.