The incredible uses of algae
Algae are plant-like protests; neither plant nor animal. They share many characteristics with plants due to their photosynthetic ability. As a result of their rapid growth, high density of nutrients and minimal growth requirements, algae offer a wide range of uses in a range of industries.
Food & health
Seaweed cultivation forms a major industry, particularly in Japan, China and Korea, where many algae species are grown by aquaculture. For example Nori, used to wrap sushi is one of the most valuable aquacultured crops. Dulce, a red algae is eaten raw, cooked or fried like spinach, sold primarily in Ireland and Atlantic Canada. Algae are packed full of essential micronutrients such as magnesium, calcium, potassium, iodine, iron, and zinc and are therefore used in many food supplements. For example, spirulina which is commonly used in smoothies. Blue-green algae are known to contain a wide range of bioactive substances, some of which provide a potential source for anticancer, antiviral, antibiotics, antioxidant, and antiinflammatory drugs.
Algae has long been used to fertilise crops as they provide a rich source of nutrients and organic matter. Algae can be directly deposited on the land where it decomposes or algae extract can be sprayed on the crops.
Industrial and commercial uses
The large diversity of pigments found in different algal species offer a source of natural pigments to be used as alternatives to artificial chemical dyes and colouring agents, as well as for food colouring. Natural algal pigments also prove to be much better for paper recycling as they are much more easily broken down compared to artificial chemical inks. Carrageenan is an algae widely used as a stabiliser in food, to prevent separation of the mixtures. Carrageenan can also be found as a food thickener in a range of products such as ice-cream, toothpaste and cosmetics.
Agar, the medium used in the labs to culture bacteria as well as other lab techniques such as gel electrophoresis is derived from red algae. A white powdered substance, known as diatomaceous earth is made of fossilised diatoms, a single-celled alga, that contains silica. Due to its high absorbance of liquids and fats, diatomaceous earth is used as insecticide, as the powder absorbs the waxy lipids on the surface of the insects exoskeleton causing dehydration of the insect. Other uses include cat litter, filtration-aid due to the small particle size and as a thermal insulator as it is also highly heat resistant.
Algae also hold great potential to be used as carbon-neutral fuels. Many species of microalgae have high lipid contents that can be readily extracted and converted to biodiesel. They also process high concentrations of fermentable sugars making them suitable for bioethanol production. Moreover, algae can be farmed without competing with arable land for food production, unlike other biofuel sources such as maize which results in further deforestation to clear more land for crop growth. Algae can be grown on non-arable land as long as there is some water source, as well as in laboratories in industrial-sized tanks. Therefore, algae possess a great advantage over plant-based biofuels. Current research focuses on ways of increasing the yield of biofuel production by the alteration of growth conditions and genetic modification. The future of algal biofuels has great potential.
Algae naturally produce polymers that have a great potential for bioplastic production such as starch or polyhydroxyalkanoates (PHAs). PHAs possess thermoplastic properties that don’t need to be modified to create a plastic film. Properties will vary depending on the exact structure of the PHA, the purity, molecular weight and the extracted amount of PHAs. In contrast, starch is not a polymer with plastic properties but can be modified with additives to achieve thermoplastic properties or used as a filler in other plastics. The low lignin content and high percentage of carbohydrates are properties that make algae an excellent resource for the production of bioplastics. Algae is also completely biodegradable so offer an environmentally-friendly alternative to oil-based plastics that are causing severe problems for the environment. Algae have already been used to make many biodegradable plastics such as the biodegradable water bottles by Ari Jónsson made simply by mixing agar powder and water, before rapidly cooling it and turning it in an ice-cold mould. The bottle keeps its shape whilst full of water, but will start to decompose when empty. Liquids stored in the bottle are entirely safe to drink, and the bottle itself can even be eaten!
Algae can also be used in wastewater treatment as they metabolise and breakdown waste substances, thereby reducing the need for toxic chemicals to be used. Some algae can also be used to capture fertiliser runoffs, therefore preventing harmful effects of eutrophication as less enters aquatic systems. Algae are also used in some power plants to reduce CO2 emissions as it is captured and utilised but the algae for photosynthesis.
Algal biotechnology is still a young field of research that is expected to grow in the next years due to the great potential algae holds for finding sustainable, alternatives to help meet the needs of society as well as preserving the environment. Current production costs of algal bioplastics and fuels are still high, but with biotechnological advancements prices are expected to decrease, making them a more viable option.