Production, process optimization and molecular characterization of polyhydroxyalkanoate (PHA) by CO₂ sequestering B....

Area of Science:

• Microbiology
• Biotechnology
• Polymer Science

Background:

• Bacterial strains capable of sequestering carbon dioxide (CO2) were previously identified in enriched soil environments.
• Polyhydroxyalkanoates (PHAs) are biodegradable polyesters with significant industrial potential, but their efficient production remains a challenge.

Purpose of the Study:

• To screen previously isolated CO2-sequestering bacterial strains for polyhydroxyalkanoate (PHA) accumulation.
• To characterize the PHA accumulating capabilities of Bacillus cereus SS105 and optimize its production.

Main Methods:

• Screening of bacterial isolates for PHA accumulation using sodium bicarbonate and molasses as carbon sources.
• Characterization of PHA granules via Spectrofluorometry, Confocal microscopy, and Transmission Electron Microscopy.
• Analysis of PHA composition using Gas Chromatography-Mass Spectrometry (GC-MS), Fourier-Transform Infrared Spectroscopy (FTIR), and Nuclear Magnetic Resonance (NMR).
• Confirmation of PHA biosynthesis gene involvement (phaR, phaB, phaC) through PCR amplification and cloning.
• Optimization of PHA production using Response Surface Methodology (RSM).

Main Results:

• Bacillus cereus SS105 was identified as the most prominent PHA-accumulating strain.
• PHA granules were successfully visualized and characterized, with monomer composition analyzed.
• Key PHA biosynthesis genes were confirmed in B. cereus SS105.
• Response Surface Methodology optimization resulted in a 55.16% increase in PHA production (w/v).

Conclusions:

• Bacillus cereus SS105 is a promising candidate for efficient polyhydroxyalkanoate (PHA) production.
• The study successfully characterized PHA production and identified key genetic components.
• Optimized production conditions significantly enhanced PHA yield, highlighting the potential for industrial application.