London, November 14 (BTI). The violet bacteria that store energy from the light can help to collect hydrogen fuel from waste water and recover carbon from any kind of organic waste, scientists have found.
Organic compounds in municipal waste water and industrial waste water are a rich potential source of energy, bioplastics and even animal feeds, but without an effective extraction method, purification plants dispose of them as pollutants.
The study, published in Frontiers in Energy Research, is the first to show that the supply of electricity to violet phototropic bacteria can recover almost 100 percent of carbon from any organic waste, while generating hydrogen gas for electricity generation.
"One of the most important problems in current wastewater treatment plants is the high carbon footprint," said Daniel J., The Royal Juan Carlos University of Spain.
"Our light biorefinery process could provide the means to collect green energy from wastewater with zero carbon footprint," said Pujols.
Violet phototrophic bacteria capture energy from sunlight using a variety of pigments that turns them into orange, red or brown hues, and purple.
"Violet phototropic bacteria are an ideal vehicle for the recovery of organic waste due to their very diverse metabolism," said Pujols.
Bacteria can use organic molecules and nitrogen gas instead of carbon dioxide and water to provide photosynthesis of carbon, electrons and nitrogen.
This means that they grow faster than alternative phototropic bacteria and algae, and can also produce hydrogen gas, protein or biodegradable polyester as metabolic by-products.
Which metabolic product is predominantly dependent on bacterial environmental conditions, such as light intensity, temperature, and available organic substances and nutrients.
"Our group is manipulating these conditions to adjust the metabolism of purple bacteria for various uses, depending on the source of organic waste and market requirements," said Abraham Esteve-Nunez of the University of Alcala in Spain.
"But what's unique about our approach is the use of external electrical energy to optimize the productive output of wool bacteria," he said.
The researchers analyzed the optimal conditions for maximizing hydrogen production using a mixture of purplish-phototropic bacterial species.
They also tested the effect of the negative current – that is, the electron supplied by the metal electrodes in the culture medium – on the metabolic behavior of the bacteria.
The first main conclusion was that a nutrient mix that feeds the highest levels of hydrogen production also reduces CO2 production.
"It shows that purple bacteria can be used to recover valuable biofuels from organic substances that are commonly found in sewage – malic acid and sodium glutamate – with low levels of carbon dioxide," said Esteve-Nunez.
It is published in unpublished PTI feeds.