Scientists harness fruit waste to extract energy

A team of researchers led by the University of British Columbia (UBC) Okanagan has recently explored the potential of using fruit waste (both solid and leachate) to power fuel cells.

Although the energy extracted from food scraps still pales in comparison to wind or solar power, the experts are confident that the energy output of discarded food – particularly fruit waste, which is abundant in the agricultural belt of the Okanagan Valley – can be further purified and improved.

Currently, food waste is an increasing problem in cities worldwide. According to the British Columbia government, for instance, organic waste represents 40 percent of material in provincial landfills. Thus, harnessing this waste and turning it into energy would be a major step forward in solving this problem.

“Today food waste is a sustainability challenge with detrimental environmental, economic, and social implications,” said study lead author Hirra Zafar, an expert in Food Waste Management at UBC Okanagan.

“Current waste treatment methods, such as landfills and incineration, are associated with a wide range of adverse environmental impacts, including acidic waste leachate, air pollution, methane production, and the release of harmful pollutants that result in environmental degradation and health risks.”

The scientists found that microbial fuel cells can efficiently convert fruit waste into electric energy by using an anaerobic anode compartment in which anaerobic microbes – a type of microorganisms that can survive without oxygen – utilize organic matter to convert it into energy. These microbes consume organic matter in the anode compartment, releasing electrons and protons. 

In the cathode compartment, the electrons combine with the protons and oxygen to produce water, generating bioelectricity in the process. According to the researchers, this process works more efficiently and produces better output when the food waste is separated and ground into small particles before processing.

Due to their individual biochemical features, different types of fruits lead to different results when processed through microbial fuel cells.

“Carbohydrates are first degraded into soluble sugars and smaller molecules such as acetate, which is then consumed by electroactive bacteria to produce electricity in the process of electrogenesis,” Zafar explained.

Although many challenges remain in converting food waste into bioenergy on a commercial scale – with further work needed to increase the bioconversion efficiency of fruit to result in higher voltage outputs – these findings highlight the great potential of microbial fuel cells. 

“Microbial fuel cells are really at their developmental stage and they have so much potential. At this point, the voltage remains low, but I am excited to investigate how to improve their power output and apply these practices on a commercial scale,” Zafar concluded.

The study is published in the journal Bioresource Technology.

More about fruit waste

Fruit waste refers to the portion of fruits that is discarded, not consumed, or left unutilized during various stages of the supply chain, from production to consumption. This waste can occur at multiple points, such as during harvesting, storage, transportation, processing, and retail. Fruit waste can also happen at the consumer level, where fruits may be thrown away due to spoilage, cosmetic imperfections, or over-purchasing.

There are several reasons for fruit waste:

Cosmetic standards

Fruits that do not meet the specific shape, size, or color requirements may be discarded, even if they are perfectly edible and nutritious.

Oversupply

Sometimes, the market demand for certain fruits is lower than the supply, leading to waste.

Poor storage and transportation

Inadequate storage and transportation facilities can lead to spoilage or damage, rendering fruits unsuitable for consumption.

Lack of proper harvesting techniques

Inefficient or improper harvesting methods can lead to waste, as fruits may be left in the fields or damaged during the process.

Consumer behavior

Consumers may not store fruits properly, leading to spoilage, or may throw away fruits that are still edible due to perceived imperfections.

The impacts of fruit waste

Fruit waste has significant environmental, economic, and social impacts. It contributes to the depletion of natural resources, increased greenhouse gas emissions, and the squandering of water, energy, and land resources. Economically, it leads to financial losses for farmers, retailers, and consumers. Socially, it is a missed opportunity to address food insecurity and malnutrition.

To mitigate fruit waste, various strategies can be employed, such as implementing better harvesting, storage, and transportation methods to minimize spoilage and damage. Consumers should be encouraged to use “ugly” or “imperfect” fruits, which are still edible.

In addition, consumers should plan their purchases, store fruits properly, and consume them before they spoil. By addressing fruit waste, we can reduce the negative impacts on the environment, economy, and society, while also making better use of our resources.

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By Andrei Ionescu, Earth.com Staff Writer

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