While studying the possibilities of waste recycling, researchers at a Swedish university have come up with an unlikely suspect for an alternative fuel source - the orange.

Mohammad Taherzadeh and his research team at the School of Engineering at the University of Borås in Sweden have previously succeeded in producing ethanol and biogas from different kinds of waste and have now focused on citrus waste in particular.

Citrus waste is usually a complete write-off in the compost game because it contains an antibacterial substance which slows its breakdown, but the research team has discovered that these acidic skins have more uses than they receive credit for.

The researchers have developed a method of producing four products from the citrus waste: limon, an antibacterial agent, pectin, a gelling agent used in foods such as jams and jellies, biogas, a gas that can be compressed and used to power motor vehicles, and ethanol, a liquid that has a long history as a fuel for heat and light.

Both Mohammad Taherzadeh and Daniel Yar Hamidi are convinced that facilities converting citrus waste into these products would be successful, especially in countries with a warm climate and citrus cultivation.

“In such places there is an even greater need for this type of facility. In Borås we have about 10,000 tones of citrus waste per year,” Mr Taherzadeh said.

“We need to be even better than we are today in Sweden. If we do it in the right way, we can sell our knowledge as an export and at the same time improve the global environment.”

A patent application for the process has recently been submitted to the Swedish Patent and Registration Office.

The FPL Energy ethanol plant in Florida is also developing plans to build a commercial plant that will convert orange and grapefruit waste into ethanol that will be sold to Florida motorists at gasoline pumps.

The FPL plant is expected to produce about 4 million gallons of ethanol a year to be sold as a gasoline additive in Florida.