Cold-loving bacteria could hold key to green and energy-saving detergents

Biosurfactants, which are produced by microorganisms, are surface-active molecules composed of hydrophilic (water-loving) and hydrophobic (water-repelling) portions as their constituents. These components reduce surface tension and interfacial tension between both aqueous solutions and hydrocarbon mixtures. Thanks to their relatively non-toxic and biodegradable character, as well as their ease of production from renewable materials, biosurfactants are considered a possible green alternative to chemical surfactants for several commercial products, such as detergents and cleaners, personal care products, cosmetics, pharmaceuticals and food additives.

Scientists exploring the biodiversity of microbial biosurfactants produced in low-temperature environments looked into the commercial potential of these environmentally friendly biomolecules, with contributions from the EU-funded BioFrost project.

Writing in the journal ‘Trends in Biotechnology’, the research team from the GFZ German Research Centre for Geosciences and Ulster University proposed future strategies to increase the industrial competitiveness of biosurfactants.

Quoted by the GFZ German Research Centre for Geosciences, one of the authors of the report, Dr Amedea Perfumo, said biosurfactants have “tremendous potential.” They can be produced using affordable waste products such as olive oil by-product and cooking oils. Due to their ability to work in lower concentrations, they can get the same job done even when used in smaller quantities. She also highlighted biosurfactants’ extra feature: their ability to function in freezing temperatures.

In the journal article, scientists noted that the addition of biosurfactants could make biodiesel a viable fuel option by enabling it to flow more smoothly at colder temperatures. Biodiesel is a renewable green fuel that burns cleaner than gasoline and can be manufactured from low-cost and waste materials such as vegetable oils, animal fats and recycled cooking oil. As pointed out in the same study, these biosurfactants could also allow detergents to be activated at colder washing temperatures. This helps to conserve energy.

Avoiding the downside of cold washing

To make sure that clothes are clean at lower temperatures, the innate antimicrobial, antiadhesive and biofilm-degrading activities of many biosurfactants could be exploited, the scientists argued. A biofilm comprises bacteria held together by a mucus-like matrix of carbohydrate that sticks to a surface. “As such, when incorporated in laundry product formulations biosurfactants would have a dual action, as both detergents and bactericides,” the scientists explained. They added that biosurfactants could also be used to clean up pollution in cold ocean water. According to Perfumo, scientists who don’t have the option to personally go to the polar regions and take samples “can simply get organisms from culture collections. It''s in reach for everybody.”

The cold-active enzymes created by extremophilic bacteria – those thriving under extreme conditions of temperature, pressure or chemical concentration – are already being synthesised for industrial purposes. According to Perfumo, biosurfactants are next in line. The scientists concluded that there are aspects of biosurfactants related to both fundamental research and experimental approaches “that need to be tackled with greater effort” to advance further with their use and applications.

The BioFrost (Life at its extremes: Biodiversity and activity of microorganisms in deep permafrost) project, which ended in 2017, investigated how microorganisms survive in the deep biosphere of the Earth’s permafrost, where temperatures are sub-zero and oxygen is lacking.