Biodegradation of Poly-β-hydroxyalkanoates in anaerobic sediments

The use of biodegradable plastics has been proposed as a solution to the problem of plastic waste. Poly-β-hydroxyalkanoates (PHA), produced exclusively by prokaryotic microorganisms, can be used as thermoplastics and are fully biodegradable and innocuous to the environment. Biodegradability testing has been developed to quantify the capability of micro-organisms to degrade these compounds. However, laboratory conditions set up to run biodgradability tests do not totally represent the natural environmental conditions that plastic waste may encounter. Microcosmos simulating microbial ecosystems, such as sulfureta (anaerobic sediments), have been studied to assess the degradation potential of PHA in natural conditions. Sulfate-reducing bacteria are known to play an important role in carbon recycling in anaerobic sediments. We show that they also have a decisive contribution to the biodegradation of PHA in such environments. Besides, in this paper, various techniques used to assess PHA biodegradability are reviewed.