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Тhe conversion of waste cooking oil to degradable polymer
polyhydroxyalkanoate (PHA)
Mihajlo Stošić

Regional Center for talented youth Beograd II, mihajlomik96ferrari@gmail.com
1. Introduciton
In the second part of the work we wanted to establish
whether the isolated microorganism has the ability to
Nowadays, the materials and products with non-existent or accumulate PHA. As a positive control, we used species
not fully developed recycling process from which we could
obtain products that could be used again, present a major Ralstonia eutropha H16, which in its genome shows the
presence of lipase, and also has the ability of PHA
problem.
There are several methods of waste edible oils processing accumulation [3].
Ralstonia eutropha H16 had the ability to grow on both
such as production of biodiesel [1], or, as a more advanced
method, its use for the synthesis of bacterial biopolymers - concentrations of oil from the fryer, while the amount of
accumulated PHA was 10 and 12% of the total cell mass.
polyhydroxyalkanoates (PHA) [2]. Polyhydroxyalkanoates
(PHA) are linear polymers composed of (R) -3-hydroxy Unexpectedly, increasing the amount of oil, did not result in
a proportionate increase in the quantity of accumulated
fatty acids, formed by fermentation of sugars or lipids, and
are stored inside the bacterial cells. PHA. Compared with some carbohydrates as a source of
carbon, oil from the fryer is a significantly poorer substrate
The aim of this paper is to determine whether in the used
oil from fryers there are microorganisms that can synthesize for the production of PHA. Namely, Ralstonia eutropha can
accumulate up to 80% PHA from fructose.
polyhydroxyalkanoates from waste oil, and what is the
minimum amount of waste oil needed to produce PHAs
with the known strains, which, with further purification and
processing, could be used in the production of bioplastics.

2. Work methods

Figure 1. Samples of bacteria grown on solid MSM
In this paper, we used oil from the fryer as a source of
nutrients for microorganisms. We used Ralstonia eutropha substrates
H16 from commercial strains. Microorganisms were grown
in LA and MSM substrates under standard laboratory
conditions for a period of 5 days. Identifying the unknown
bacteria strain was carried out by 16S rDNA sequencing in
Biosystems 3130 Genetic Analyzer. The amount of
polyhydroxyalkanoates was determined by using gas
chromatography.
Figure 2. A) The amount of the accumulated PHA B) A
3. Research results typical gas chromatogram which indicates the presence of
PHA and fatty acids in the sample.
In the first part of this paper, we tried to determine whether 4. Conclusion
the waste edible oil from fryers contains microorganisms
that can grow on this substrate as the sole carbon source, This study suggests that in the oil from the fryer there are
and whether these microorganisms can accumulate bacteria that are able to use it as a source of carbon, but
bioplastic, i.e. polyhydroxyalkanoate. without the possibility of accumulation of polyhydroxy-
By direct application of oil on the solid supports, we alkanoates, and can serve as a substrate for PHA
obtained the growth of one type of micro-organisms, which accumulation for commercial strains, and that it can serve
was subcultured on MSM substrate which contained Tween as a substrate for PHA accumulation, but it is necessary to
80, or glucose as a carbon source. The isolated further optimize the bioprocess, so that it could be applied
microorganism had the ability to grow on both types of on a larger scale.
carbon, but had no ability of polyhydroxyalkanoate
accumulation. (Figure 1). 5. Bibliography
The isolated microorganism was identified by molecular
biological methods, ie. by sequencing genes for 16S rDNA. [1] Vera, C.R.; S.A. D'Ippolito, C.L. Pieck, J.M.Parera
Analyses have shown that the first strain is 98% identical to (2005-08-14). "Production of biodiesel by a two-step
Stenotrophomonas maltophilia, and the second strain is supercritical reaction process with adsorption refining"
97% identical to Pseudomonas geniculata. [2] Jacquel, N.; et al. (2008). "Isolation and purification of
bacterial poly(3-hydroxyalkanoates)". Biochem. Eng. J.
[3] Gregory M. York; et al. (2003) Ralstonia eutropha H16
Encodes Two and Possibly Three Intracellular Poly[D-(R)-
3-Hydroxybutyrate]