Biosynthesis and mobilization of poly(3-hydroxybutyrate) [P(3HB)] by Spirulina platensis.
Three strains of Spirulina platensis isolated from different locations showed capability of synthesizing poly(3-hydroxybutyrate) [P(3HB)] under nitrogen-starved conditions with a maximum accumulation of up to 10 wt.% of the cell dry weight (CDW) under mixotrophic culture conditions. Intracellular degradation (mobilization) of P(3HB) granules by S. platensis was initiated by the restoration of nitrogen source. This mobilization process was affected by both illumination and culture pH. The mobilization of P(3HB) was better under illumination (80% degradation) than in dark conditions (40% degradation) over a period of 4 days. Alkaline conditions (pH 10-11) were optimal for both biosynthesis and mobilization of P(3HB) at which 90% of the accumulated P(3HB) was mobilized. Transmission electron microscopy (TEM) revealed that the mobilization of P(3HB) involved changes in granule quantity and morphology. The P(3HB) granules became irregular in shape and the boundary region was less defined. In contrast to bacteria, in S. platensis the intracellular mobilization of P(3HB) seems to be faster than the biosynthesis process. This is because in cyanobacteria chlorosis delays the P(3HB) accumulation process.
Jau
Mei-Hui
MH
School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia.
Yew
Saw-Peng
SP
Toh
Pamela S Y
PS
Chong
Alexander S C
AS
Chu
Wan-Loy
WL
Phang
Siew-Moi
SM
Najimudin
Nazalan
N
Sudesh
Kumar
K
D000255:Adenosine Triphosphate / Q000737:chemistry; D001426:Bacterial Proteins / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002244:Carbon / Q000737:chemistry; D002849:Chromatography, Gas; D000458:Cyanobacteria / Q000737:chemistry / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006885:Hydroxybutyrates / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D009584:Nitrogen / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry*; D053545:Spirulina; D013696:Temperature; D020524:Thylakoids / Q000378:metabolism; D013997:Time Factors; D014466:Ultraviolet Rays; D000094122:Polyhydroxybutyrates
D000255:Adenosine Triphosphate; D001426:Bacterial Proteins; D002244:Carbon; D006885:Hydroxybutyrates; D046911:Macromolecular Substances; D009584:Nitrogen; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates