Bioconversion of Groundnut Oil into Polyhydroxyalkanoate (PHA) by Bacillus Subtilis LO1

Area of Science:

• Microbiology
• Biotechnology
• Polymer Science

Background:

• Polyhydroxyalkanoates (PHAs) are microbial biopolymers offering eco-friendly alternatives to petrochemical plastics.
• Their production is triggered by nutrient limitation in microorganisms.
• PHAs possess desirable properties like biodegradability and non-toxicity for diverse applications.

Purpose of the Study:

• To isolate and identify a PHA-producing bacterium from contaminated soil.
• To optimize conditions for enhanced PHA synthesis using groundnut oil.
• To characterize the produced PHA for potential applications.

Main Methods:

• Isolation and identification of PHA-producing bacteria from lubricating oil-contaminated soil.
• Optimization of growth parameters (pH, temperature, incubation time, nutrient concentrations) for PHA production.
• Cultivation using a two-stage shake flask method with groundnut oil as the carbon source.
• Characterization of the extracted PHA using Fourier Transform Infrared Spectroscopy (FT-IR) and Gas Chromatography-Mass Spectrometry (GC-MS).

Main Results:

• Bacillus subtilis (MK071733) strain LO1 was identified as a prominent PHA producer.
• Optimized conditions (pH 7, 35°C, 72h incubation, specific nutrient levels) significantly enhanced PHA yield.
• A yield of 5.52 g/L PHA (cell dry weight) was achieved from 9.8 g/L bacterial dry cell weight.
• FT-IR and GC-MS analysis confirmed the presence of medium-chain-length (mcl) PHA copolymers.

Conclusions:

• Bacillus subtilis LO1 is a capable producer of mcl-PHAs.
• Optimized cultivation strategies can maximize PHA yield from sustainable carbon sources like groundnut oil.
• The characterized PHA holds potential as a biodegradable substitute for conventional plastics.