Screening, optimization and characterization of poly hydroxy butyrate from fresh water microalgal isolates

ABSTRACT

Microalgae, especially Chlorella sp., have been used for centuries as food and currently their biotechnological potential is notable for the presence of several compounds relevant to the market, like PHB. Microalgae are appealing because of the increasing demand for biopolymers like PHB. Therefore, the present study is aimed to determine the efficacy of biomass production and yield of PHB producing microalgae isolated and identified by phylogenetic analysis. The parameter was optimized as pH 7, temperature 30°C, under sunlight with 0.2% of sodium bicarbonate for higher biomass and PHB production. The extracted PHB were characterized through SEM, EDAX, XRD and FT-IR. In GC-MS analysis the major peak represents Benzyl butyl phthalate confirming the polymer of PHB. DSC-TGA, was performed and the melting peak of PHB was found as 342.1°C conferring to thermogravimetric analysis, the range of temperature for rapid thermal degradation of PHB was at 418°C to 420°C with the degradation peaking at 418.2°C the total weight loss within this temperature range was 98.5%. Hence, maximum 80% of PHB was produced from Chlorella sp. in addition to sequestering CO_2.

KEYWORDS:

• Chlorella sp
• poly-β hydroxybutyrate
• optimization
• GC-MS
• DSC-TGA

Highlights

• Among 27 phytoplanktons’s, Chlorella sp. Neochloris sp. was isolated from freshwater.

• The optimization studies on Chlorella sp. showed maximum  PHB production.

• Characterized through SEM, EDAX, XRD, FT-IR.

• The presence of Benzyl butyl phthalate confirming the PHB through GC-MS analysis.

• TGA & DSC confirmed the presence of PHB.

• Maximum (80%) PHB was produced from Chlorella vulgaris.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the University Research Fellow [DST-FIST (Ref No.SR/FST/LSI–640/2015(C)]; National Fellowship and Scholarship for Higher Education (NFST) [Award No: 201718-NFST-TAM-00157].

Notes on contributors

Kanaga Selvaraj

Kanaga Selvaraj, Research Scholar, Fermentation research Laboratory, Department of Microbiology, Periyar University, Salem-636011, India. [email protected]

Nandhini Vishvanathan

Nandhini Visvanathan, MSc., Student, Fermentation research Laboratory, Department of Microbiology, Periyar University, Salem-636011, India. [email protected] 

Ramamurthy Dhandapani

Dhandapanij RamamurthyAssistant Professor, Fermentation research Laboratory, Department of Microbiology, Periyar University, Salem-636011, India. [email protected]