What do people do with rotten and spoiled tomatoes? They produce electricity from them – at least that will be the answer a few years from now. If scientists can have their way, spoiled and rotten tomatoes, and other citrus fruits, will be used to produce electricity.
A group of student researchers from South Dakota School of Mines & Technology, Princeton University and Florida Gulf Coast University have developed a prototype fuel cell that runs on rotten tomatoes. Just in Florida, 3,96,000 tons of tomato go waste every year. Just imagine, instead of throwing these tomatoes away, if electricity can be produced from them.
According to Professor Gadhamshetty Venkatramana, a team leader of the project, “We wanted to find a way to treat this waste that, when dumped in landfills, can produce methane – a powerful greenhouse gas – and when dumped in water bodies, can create major water treatment problems.”
But how can they produce electricity from rotten and spoiled tomatoes? Namita Shrestha, a PhD student at the South Dakota School of Mines & Technology says, “We have found that spoiled and damaged tomatoes left over from harvest can be a particularly powerful source of energy when used in a biological or microbial electrochemical cell. The process also helps purify the tomato-contaminated solid waste and associated wastewater.”
As mentioned above, the state of Florida produces 3,96,000 tons of rotten and spoiled tomatoes and according to the research team, even with current technology, these many rotten and spoiled tomatoes can produce enough energy to power Disney World for 3 months.
The researchers have developed microbial gel batteries that can generate electric current from rotten tomatoes. The microbial electrochemical cells break down and oxidise organic material in the spoiled tomatoes with the help of bacteria. The entire process of breaking down and oxidizing organic material with bacteria releases electrons and hence, electricity.
According to Professor Gadhamshetty, typically biotechnological applications need pure chemicals in order to give better results but surprisingly, spoiled tomatoes didn’t just give the same results, but even better.
He said that there is a pigment found in rotten and spoiled tomatoes called lycopene that acts as an excellent mediator that generates electrical charges from spoiled fruits. The spoiled tomatoes from Florida, for example, if not being consigned to the landfills, can be a rich source of indigenous redox mediators and carbon as well as electrons.
How much power right now can be actually produced from rotten tomatoes? Right now the output is quite small. 10 milligrams of rotten tomatoes right now produce 0.3 watts of electricity. This means 200 cells will be needed to power a 60-watt light bulb. But then this is just the beginning. Besides, right now, the real objective of the research is not to start producing electricity and powering Disney World. According to Professor Gadhamshetty, “Our research question at this time is to investigate the fundamental electron transfer mechanisms and the interaction between the solid tomato waste and microbes.”