Following the rising concern on environmental issues caused by conventional fossil-based plastics and depleting crude oil resources, polyhydroxyalkanoates (PHAs) are of great interest by scientists and biodegradable polymer market due to their outstanding properties which include high biodegradability in various conditions and processing flexibility. Many polyhydroxyalkanoate-synthesizing microorganisms, including normal and halophilic bacteria, as well as algae, have been investigated for their performance in polyhydroxyalkanoate production. However, to the best of our knowledge, there is still limited studies on PHAs-producing marine yeast. In the present study, a halophilic yeast strain isolated from Spratly Island in Vietnam were investigated for its potential in polyhydroxyalkanoate biosynthesis by growing the yeast in Zobell marine agar medium (ZMA) containing Nile red dye. The strain was identified by 26S rDNA analysis as Pichia kudriavzevii TSLS24 and registered at Genbank database under code OL757724. The amount of polyhydroxyalkanoates synthesized was quantified by measuring the intracellular materials (predicted as poly(3-hydroxybutyrate) -PHB) by gravimetric method and subsequently confirmed by Fourier transform infrared (FTIR) spectroscopic and nuclear magnetic resonance (NMR) spectroscopic analyses. Under optimal growth conditions of 35 °C and pH 7 with supplementation of glucose and yeast extract at 20 and 10 gL−1, the isolated strain achieved poly(3-hydroxybutyrate) content and concentration of 43.4% and 1.8 gL−1 after 7 days of cultivation. The poly(3-hydroxybutyrate) produced demonstrated excellent biodegradability with degradation rate of 28% after 28 days of incubation in sea water.

Nowadays, polyhydroxyalkanoates (PHAs) is of great interest by scientists and biodegradable polymer market due to their outstanding properties such as high biodegradability in various conditions and processing flexibility. Many PHAs-synthesizing microorganisms, including normal and halophilic bacteria, and algae, were investigated. However, to the best of our knowledge, there is still little studies on PHAs-producing marine yeast. In the present study, a halophilic yeast strain isolated from Spratly Island in Vietnam were investigated for synthesis of PHA by growing the yeast in a specific medium containing Nile red dye. The strain was identified by 26S rDNA analysis as Pichia kudriavzevii TSLS24 and registered at Genbank database under code OL757724. The amount of PHA synthesized was quantified by measuring the intracellular materials (predicted as PHA) by gravimetric method, subsequently confirmed by Fourier transform infrared spectroscopic and nuclear magnetic resonance spectroscopic analyses. Under optimal growth conditions of 35 oC and pH 7 with supplementation of glucose and yeast extract at 20 and 10 g/L, the strain isolated achieved PHA content and concentration of 43.4% and 1.8 g/L. Degradation rate of PHA produced was 28% after 28 days of incubation in sea water.

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