African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12191

Full Length Research Paper

Production of polyhydroxyalkanoates by hydrocarbonaclastic bacteria

Mwamburi Samuel M.
  • Mwamburi Samuel M.
  • Institute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
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Mbatia Betty N.
  • Mbatia Betty N.
  • School of Pharmacy and Health Sciences, United States International University - Africa, Nairobi, Kenya.
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Remmy Kasili
  • Remmy Kasili
  • Institute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
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Kirwa Edward M
  • Kirwa Edward M
  • School of Medicine, Department of Biochemistry, University of Nairobi, Nairobi, Kenya.
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Noah Naumih M.
  • Noah Naumih M.
  • School of Pharmacy and Health Sciences, United States International University - Africa, Nairobi, Kenya.
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  •  Received: 06 February 2019
  •  Accepted: 01 April 2019
  •  Published: 24 April 2019

Abstract

Production of polyhydroxyalkanoates (PHA) by bacteria isolated from spent engine oil (SEO) contaminated soils was investigated using nitrogen limitation in the production medium. Out of ten isolates, three were selected as the best based on their ability to metabolize SEO effectively and fluoresce orange when stained with Nile Blue A dye. Fourier Transform Infrared spectrophometer was used as a confirmatory test for PHA detection by tracking the carbonyl bands on the spectra. Optimum growth of the isolates occurred at 1% (v/v) SEO, pH 7, 37°C for K1+VE and Kar5+VE1 while for Kar5+VE2 was at 1% (v/v) SEO, PH 7, 40°C and 150 RPM. Sequencing of 16S rDNA partial genes grouped the isolates into 6 different genera: Ochrobactrum, Pseudoxanthomonas, Bodetella, Achromobacter, Alcaligenes and Acinetobacter species. Isolate K1+VE, identified as an Ochrobactrum produced Poly (3-hydroxyheptanoate) 46% (w/w), isolate Kar5+VE1, identified as Achromobacter spp.  produced poly (3-hydroxybutyrate) 20% (w/w)) while isolate Kar5+VE2, identified as an Alcaligenes spp. produced a co-polymer poly-3- (3-hydroxybutyrate-Co-3-hydroxyoctanoate) 45% (w/w). Orthoxylene and ethylbenzene were the major hydrocarbons in spent engine oil before degradation while ethylhexanol was the major degradation product as identified by Gas Chromatography-Mass Spectrophotometry. The isolates were able to degrade hydrocarbons as well as produce polyhydroxyalkanoates.

 

Key words: Polyhydroxyalkanoates, spent engine oil, 16S rDNA, co-polymer.