PHA (polyhydroxyalkanoates) are polyesters produced by bacteria, which are an alternative to petroleum-based plastics. There are various ways to extract the bioplastic from the bacteria, but these are often inefficient and not environmentally friendly. Now, researchers at the Centre for Biological Research (CIB-CSIC) in Madrid developed a new way to extract the bioproduct, using predatory bacteria.

The bacteria that produce the material can produce op to 90 per cent of their own weight as bioplastic. The polymer, however, is contained inside the cell and therefore difficult to extract.

The aim of the study is to create a way to sustainably produce PHA while also reducing the costs and improve the downstream process. To realise this, they used a bacterium that preys upon other bacteria, called Bdellovibrio bacteriovorus. The predator was genetically redesigned to transform into a biological tool that enables the disruption of the bioplastic-producing bacteria. The B. bacteriovorus is engineered in such a way that it doesn’t degrade the bioplastic in its prey.

Thanks to the new extraction method, which is already patented, there is no need for complex equipment or toxic compounds to create PHA.

The same method could also be used to obtain other compounds, such as enzymes or proteins accumulated in other bacteria. B. bacteriovorus attacks a wide variety of bacterial strains, including those most widely used in the industry. They are safe to use by humans, however, as they do not attack mammalian cells.

This is the first time that predatory bacteria have been used to recover intracellular products of industrial interest, according to the researchers. Some companies have already shown interest in the method.

Photos: CIB / Wikimedia