Assessing PHA purity by unusual methods

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One of the biggest environmental issues of our time is without doubt the ever- increasing amount of waste. In dumps are accumulated synthetic polymers, which naturally degrade for several decades and the only possible solution to reduce the problems with these materials is recycling. One of the possible solutions, that could help is to find new biodegradable materials that are naturally decomposed in relatively short time and has similar properties to synthetic plastics. Polyhydroxyalkanoates (PHA) appear to be quite promising candidates. These materials are accumulated by numerous prokaryotes in form of intracellular granules. Unfortunately, work with live microorganisms that form natural biopolymers, carries its own pitfalls. Biotechnological production of PHA is at this time more expensive than production of synthetic plastics. However, price can be reduced in various ways, e.g. utilization of inexpensive substrates, more efficient fermentation, isolation and purification processes. Conventional isolation procedures provides high purity of PHA by using organic solvents such as chloroform, but work with these compounds brings many problems (ecological, economical…). On the contrary, alternative approaches rely on more or less selective degradation of residual bacterial biomass (other than PHA) by various chemical such as sodium hypochlorite or NaOH. Regardless of the selected isolation approach, estimation of purity of isolated polymers and identification of major impurities is of crucial importance. Therefore, we evaluated several non-commonly used techniques which can be used for assessment of PHA purity such as elemental analysis, vibrational spectroscopy (ATR- FTIR, Raman) or thermal analysis (TGA) and compared them with current method of choice – gas chromatography (GC-FID). According to our results, these alternative methods provide valuable information not only about purity of the materials, but also enable identification of potential impurities and, hence, help to minor and evaluate PHA isolation process.

Polyhydroxyalkanoates, isolation procedures, elemental analysis, vibrational spectroscopy (ATR- FTIR, Raman) or thermal analysis (TGA), gas chromatography

CHYTILOVÁ, A.; SEDLÁČEK, P.; ENEV, V.; OBRUČA, S.

10. 4. 2017

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