Washington University scientists have demonstrated that purple bacteria can be used to produce biodegradable bioplastics. This discovery promises a sustainable alternative to conventional plastics, with significant environmental benefits.
In a world drowning in petroleum-based plastics, researchers are striving to develop ore sustainable and eco-friendly alternatives. Two groundbreaking studies by biologists at Washington University in St. Louis suggest that purple bacteria might be the key to this problem. These microscopic organisms can potentially be harnessed to produce bioplastics, offering a significant environmental advantage over traditional plastic production.
Graduate student Eric Conners and research lab supervisor Tahina Ranaivoarisoa led the studies under the guidance of Arpita Bose, an associate professor of biology at WashU. Their work revealed that certain species of purple bacteria could be coaxed into producing polyhydroxyalkanoates (PHAs), natural polymers that can be used to make biodegradable plastic.
“There’s a huge global demand for bioplastics,” Bose said in a news release. “They can be produced without adding CO2 to the atmosphere and are completely biodegradable. These two studies show the importance of taking multiple approaches to finding new ways to produce this valuable material.”
Purple bacteria are unique aquatic microbes known for their ability to adapt and create useful compounds from simple ingredients. Unlike plants, which use green chlorophyll for photosynthesis, purple bacteria utilize different pigments to capture sunlight. This allows them to convert carbon dioxide into food and other compounds, including PHAs.
The researchers, publishing their findings in Microbial Biotechnology, discovered two relatively unknown species of purple bacteria within the genus Rhodomicrobium that are particularly adept at producing polymers. When the bacteria were energized with small amounts of electricity and provided with nitrogen, they exhibited a striking ability to generate PHAs continuously.
“It’s worth taking a look at bacteria that we haven’t looked at before,” Conners said in the news release. “We haven’t come close to realizing their potential.”
Rhodomicrobium bacteria have unique properties that differentiate them from other purple bacteria. Unlike free-floating cells, they form interconnected networks, which appear to be especially efficient at producing PHAs.
“It’s a unique bacteria that looks very different from other purple bacteria,” added Conners.
Additionally, the WashU team made strides with another type of purple bacteria by using genetic engineering. Published in Applied and Environmental Microbiology, their research focused on Rhodopseudomonas palustris TIE-1, a species previously not very productive in terms of PHA output. With a series of genetic modifications, the researchers significantly enhanced the polymer production of these bacteria.
“TIE-1 is a great organism to study, but it’s historically not been the best for producing PHA,” Ranaivoarisoa said in the news release.
One of the most effective modifications involved inserting a gene that increased the production of the enzyme RuBisCO, which aids plants and bacteria in capturing carbon from the air and water. This significantly boosted the bacteria’s PHA output, transforming TIE-1 into a biofactory for bioplastics.
Looking ahead, Bose plans to further explore the quality and potential applications of the bioplastics produced in her lab.
“We hope these bioplastics will produce real solutions down the road,” added Bose.
The innovative work of the WashU team underscores the importance of exploring diverse biological avenues to develop sustainable plastic alternatives. Their studies not only point to a promising new source of bioplastics but also highlight the potential for genetic engineering to optimize microbial production processes.
With the burgeoning global demand for eco-friendly plastic alternatives, these biotechnological breakthroughs could herald a new era of sustainable materials, promising a significant reduction in the environmental impact of plastic waste.