Exploring the polyhydroxyalkanoates production in psychrophilic/psychrotolerant bacteria

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Bacteria produce polyhydroxyalkanoates (PHA) which have great potential to replace conventional plastics due to their biodegradability. However, the main disadvantage is the high cost of production (primarily associated with the biotechnological process itself). The main advantage that extremophiles bring from the perspective of biotechnology is a reduction in the cost of sterility of the work, which is what benefits in conjunction with PHA. Additionally, there is limited research devoted to psychrophiles and psychrotolerants, microorganisms living in cold areas. In this work, the results of the screening involving seventy-eight cold-adapted bacterial strains isolated from East Antarctica, specifically from meltwater ponds and green snow, are presented. The polymerase chain reaction demonstrated the presence of genes encoding PHA synthases, namely PHA synthases class I and II. From the phenotypic testing, staining with Nile Red and Sudan Black B, FTIR spectroscopy in combination with a high-throughput microculture system (Duetz-MTPS), and gas chromatography were used to explore the bacterial biomass for the presence of PHA. Cultivation was conducted on five different media, four of which were limiting nutrients. Based on the results the highest biomass production and PHA accumulation (0.6 g/L) showed Pseudomonas sp. belonging to the green snow isolates. Interestingly, a high synthesis of PHA, specifically P(3HB), was observed on complex BHI medium with extra glucose addition, which did not provide the nitrogen limitation that is typical for the stimulation of the PHA accumulation. Although fluorescent staining did not provide indicative results for psychrophiles and/or psychrotolerants, it can be assessed that the presence of promising producers among polar bacteria was confirmed by PCR, FTIR, and GC, and the yield of PHA can be further increased by optimizing the media composition and growth conditions.

polyhydroxyalkanoates, PHA, psychrophiles, extremophilic bacteria

ŠLOSÁROVÁ, K.; BYRTUSOVÁ, D.; PERNICOVÁ, I.; AKULAVA, V.; SMIRNOVA, M.; SLANINOVÁ, E.; OBRUČA, S.; SHAPAVAL, V.

13. 9. 2023

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