Summary update
2019
Throughout this
phase we focused our research on Photobacterium sp. strain C2.2, due to
its enormous growth and PHA production potential using inexpensive biomass.
Because this strain belongs to a less studied species, Photobacterium
ganghwense, we decided to send this strain to sequence its complete genome.
In the lab, we continued the optimization of various cultivation parameters,
for this strain as well as C2.10 Leisingera sp., N16b Halomonas
venusta. We added the PM9 plate reads (which contain various osmolytes) to
the existing BIOLOG assays, with different conditions than those used
previously for the tested strains. In regards to cultivation parameters, we
focused mainly on carbon sources, testing both waste sunflower oil which was
used for frying as well as waste fish oil, which highlighted the fact that, out
of the two carbon sources, our strains can only successfully grow and
accumulate PHA on fish oil. Strains C2.2 and C2.10 were shown to be the most
capable of using this carbon source. Strain C2.2 was reanalyzed from the
perspective of its capacity to consume carbon and nitrogen through TOC
analyses, measuring leftover organic carbon and nitrogen throughout its growth
period. PHA accumulated by this strain was quantified through GC-MS on dried
cell samples, and the largest amount of PHB produced was obtained using
fructose as a sole carbon source, 1.84 g/L, with a PHB content of 51.7% of cell
dry weight (CDW). Bioreactor experiments were focused on glycerol and molasses
as carbon sources, obtaining cell cultures with optical densities (600nm)
ranging from 7 to 96 at a maximum of 48h cultivation time, cell densities much
greater than those obtained from shake flask cultures. The largest amount of
PHB obtained was from the cultivation of C2.2 with glycerol: 7.375 g PHA/L.
Lastly, we analyzed the market growth potential for PHA production at a global
scale, for which online press estimates an increase of 25% in the next five
years, as well as potential companies which could benefit from the studies done
throughout this project.
Publications:
- De actualizat : Mereuta
I., Tanase A.M., Chiciudean I., Vassu T., Stoica I., 2020. Metabolic and
molecular profiling of microbial communities following controlled kerosene
pollution in Bucharest Botanical Garden pristine soil, Polish
Journal of Environmental Studies,29(1):197–203. IF 1.186
2.
Manuscris: Ioana
Mereuta, Irina Lascu, Sorin Avramescu, Hilde Hansen, Iulia Chiciudean, Ileana
Stoica, Ana Maria Tanase; Photobacterium ganghwense C2.2: A new promising cell
factory for bioplastic production trimis,
Journal of Biotechnology
3.
oral presentation : TănaseA.M.,
Mereuță I., Lascu I., Avramescu S.M., Chiciudean I., Stoica I., Bioplastic
production using Black Sea microorganisms, International Microorganism Day
(IMD) – September 17, 2019, Bucharest, Romania,.
- Poster: Chiciudean
I., Mereuță I., Mihalachi E.L., Lascu I., Avramescu S.M., Jablonski P.,
Christensen M., Hansen H., Stoica I., Tănase A.M., Halotolerant Black Sea
bacteria for bioplastics production, Halophiles 2019 Conference, 24 – 28
June, Cluj-Napoca, Romania.
- Mereuta I.,
Chiciudean I., Lascu I., Mihalachi E.L., Jablonski P., Avramescu S.M.,
Stoica I., Tanase A.M., Black Sea newly isolated Photobacterium
ganghwense C2.2 a promising candidate for PHA production,
Biotechnology Congress 2019, April 11-13, Valencia, Spain.
