Investigating the Possibility of Producing Polyhydroxyalkanoates (PHAs) Using Hydrolysates of Napier Grass by Burkholderia Sacchari Strain
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Date
2022-02
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Addis Ababa University
Abstract
Bacteria produces Polyhydroxyalkanoates (PHAs), which are macromolecules. They are inclusion
bodies that build up as reserve resources while bacteria grow under various stress situations.
PHAs have been chosen as alternatives for the development of biodegradable polymers due to
their rapid degradability under natural environmental circumstances. The purpose of this study
was to produce reducing sugars from lignocellulosic Napier grass and examine PHA production
by the impact of temperature, pH, and culture time on growth yields by employing the produced
reducing sugars as carbon sources using response surface methodology via Box- Behnken design
BBD).
Burkholderia Sacchari strain was chosen from more than 300 bacterial strains capable of PHA
accumulating strains based on its ability to consume both hexose and pentose sugars and has a
capacity of accumulating high mass PHA granules inside its cells. At 200 rpm, optimal pH,
fermentation temperature, and incubation time for the isolate to produce the highest PHA were 7,
35 °C, and 48 hour, respectively.
When hydrolysates of Napier grass was employed as carbon sources and ammonium sulphate as
nitrogen sources, the strain was able to collect 62.1% PHA from its total biomass. The extracted
PHAs' FTIR spectra show strong peaks at wavenumbers that are unique to PHAs as C–H, CH2,
O-H, C=O, and C–O groups. The extract's resemblance appropriateness for bioplastic production
were validated by UV–Vis spectrophotometric analysis.
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Keywords
Polyhydroxyalkanoate, Napier grass, Glucose-rich hydrolysate, Box Behnken design, PHA productivity, Burkholderia Sacchari, FTIR