Bacteria can be genetically engineered to produce plastics (hence the term ‘bioplastics.’) Here the aim is to produce plastics in way that acts as an alternative to petroleum-based products. One part of the process that has not been fully optimized, until now, is with extracting the plastic material from the organisms without degrading the material. A new approach archives this through the use of a different microbe and the results are successful for a larger scale project to be run.
The process, devised at the Centre for Biological Research in Madrid, involves the use of a predatory bacteria to extract the bioproduct from inside other bacteria. The key objective is sustainability, both with the microbial process and with offering an alternative to fossil fuel based plastics.
The bacteria used to generate the plastics can be engineered to do so up to 90 percent of their cellular weight. The polymer produced resides within the bacterial cell. The main process currently used involves the use of detergents, which are designed to disrupt the bacterial cell and allow for the release of the plastic. The use of detergents can be variable and the over-use of surfactants is not, in itself, environmentally-friendly and partly negates the desire to move away from chemical treatments.
The lead researcher, Dr. Virginia Martínez, explains that as an alternative to detergents the researchers looked to an organism called Bdellovibrio bacteriovorus. This bacterium naturally feeds on other bacteria using a chemical that opens up the bacterial cell wall. By genetically modifying the organism, B. bacteriovorus can be used to disrupt the plastic producing bacteria (P. putida) and allow for the extraction of the plastic from within the bacterial cell. The genetic modification was necessary to prevent B. bacteriovorus from altering the plastic.
In trials the plastic producing bacteria have been seamlessly disrupted and the bioplastic released into the environment. In the long-term it is hoped the process will lead to industrial scale bacterial cell factories, producing reliable plastics at a low cost.
The research is published in the journal Scientific Reports and it is titled “Engineering a predatory bacterium as a proficient killer agent for intracellular bio-products recovery: The case of the polyhydroxyalkanoates.”
In related news, Digital Journal has recently covered research into ‘environmentally friendly’ plastics from the Massachusetts Institute of Technology. Here chemists have figured out the structure of a bacterial enzyme required to generate biodegradable plastic.
