Evaluation of Polyhydroxyalkanoate (PHA) Synthesis by Pichia Sp. TSLS24 Yeast Isolated in Vietnam

Abstract

Abstract 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.