Image: Johan Gunséus
Research project To protect against harmful radiation, UV filters are put in cosmetics or polymeric materials in consumer products. While UV filters are efficient in reflecting or absorbing the UV radiation, they threathen environment and health. We hypothesize that natural UV filters produced by microalgae or cyanobacteria offer a more sustainable alternative. We will in particular study Arctic species as they produce large amounts of UV filter chemicals to protect themselves during extreme sunlight under ice.
FORMAS finances this project.
The ultraviolet (UV) radiation of sunlight causes sunburn, premature skin ageing and even skin cancer. The best protection against sunburn and skin cancer of course is to avoid too much sun light, but also various sunscreens are on the market that protect our skin. Sunscreens contain UV filters, chemicals that either reflect or absorb UV light. UV filters are not only incorporated into sun lotions and various cosmetics, but are also used in many plastics and synthetic fabrics. These chemicals are added to increase the durability of e.g. cloths, outdoor furniture or plastic covers on agricultural land. The production of UV filters is increasing, currently worldwide more than 10 000 tons are produced per year.
While sunscreens are efficient to protect the human skin and plastics against UV radiation, at the same time they pose a threat to our health and the environment. In humans they can cause contact sensitivity, oestrogenicity and even tumors. In addition the widespread use of UV filters has led to a ubiquitous presence of some ingredients in rivers, lakes and the sea. UV filters enter the environment directly during bathing activities, but they also leak from outdoor products and microplastics, and are discharged with industrial and domestic wastewater. Wastewater treatment plants are not very effective at removing these contaminants. Several UV filters have been detected in surface- and wastewater, they accumulate in the food chain and cause negative effects on insects and fish and have been found to be responsible for coral bleaching, as they promote viral infections of the corals. Degradation products of UV filters can transform into even more toxic products. The European Chemicals Agency therefore has listed half of the most commonly used sunscreens in Europe as potential harmful to the environment and human health.
Natural UV filters might offer safer alternatives, and the use of algae and cyanobacteria as a source of new cosmetic ingredients is highly appealing. These organisms use sunlight to generate energy in the process of photosynthesis. Excessive sunlight is damaging even algae and cyanobacteria, they therefore protect themselves by producing natural sunscreens. These compounds are antioxidants and absorb UV-light highly efficiently. Natural sunscreen extracts from macroalgae are already used in commercial sun block preparations, however, this approach is limited by a lack of reliable supply. Microalgae and cyanobacteria instead offer commercial exploitation: they can be cultured in bioreactors, which can be placed on roof tops or non-agricultural land, they grow extremely fast and they can grow in non-potable water (sea water or even wastewater).
We will search for microalgae and cyanobacteria that are highly efficient in the production of natural sun screens. Nordic cyanobacteria and microalgae are constantly exposed to a wide range of unfavorable conditions (high light combined with low temperatures) and therefore are expected to be highly productive in the accumulation of photoprotective chemicals. At extreme conditions in the Nordic and Arctic regions it is highly important to protect the photosynthetic apparatus. These microorganisms therefore are expected to produce a large amount and/or variety of natural UV filters. In addition we also have access to culture collections with microalgae and cyanobacteria from all over the world. Once we have identified the best producing strains, we will try different methods to isolate and purify the novel natural UV filter chemicals from the cells to identify their molecular structure. Identified candidate UV filter chemicals will be screened for their potential impact on critical environmental and human health endpoints with the aim to identify the most sustainable compounds. This analysis will also include studies on their emission potential and if they pose a risk to reach drinking water resources. With the suggested interdisciplinary approach we hope to increase our understanding on microalgae and cyanobacteria as a source for a biobased sustainable production of UV-filter chemicals.
