Seaweeds are widely used in the cosmetic and food industries, and even in the production of biofuels, yet previously they were considered by some as oceanic trash, visually polluting the sands on beaches. They could responsible for transacting US$ 45 billion dollars by 2023, according to Credence Research market consultancy. There are two types of seaweed; microalgae and macroalgae. Macroalgae are aquatic plants growing directly in the ocean, and can be cultivated along coastal areas. Yet, microalgae are microscopic single cells and can be cultivated in natural or in artificial environments. Both types basically serve the same purpose: producing organic matter from inorganic matter. However, microalgae are invisible to the naked eye. Thus, they can be present in countless aquatic environments, on trees, or even in water wells. “There are around 30 thousand known identified species that is only 10% of the entire microalga universe. Some species are larger, ranging from 2 to 2000 micrometers. Those are more easily identified”, explains Flávia Saldanha-Corrêa, a biologist, who since 2014 has been the curator of the Aidar & Kutner Microorganism Bank, at the Oceanographic Institute of the São Paulo University (BMA&K). The bank was created in 1975 and houses a collection of 230 strains of microalgae available for research purposes. In the last 5 years, 70 institutions, some of these are companies and universities using these strains for performing research studies.
One advantage for using microalgae instead of macroalgae is the rapid reproduction rate. “In a short time period, it is possible to accumulate a greater amount of mass than from macroalgae. We have already performed research studies on producing biodiesel from microalga. Microalgae accumulate lipid that is a type of oil and can be converted into biodiesel, such as bio-kerosene. They produce carbohydrates, which can be converted into ethanol. I believe this is going to be the main source of renewable energy in the world in the near future”, highlights the researcher. “The potential is gigantic. As there is an extremely diverse group, there is still so much to discover”.
Exploring the potential
A research study partnership between Brazil and the Netherlands has revealed the possible usage of Chlorella specie microalgae to clean a domestic sewage while meanwhile producing organic fertilizer. “It is necessary to use chemical products in the most common sewage treatment process, in order to remove phosphorus from the water, and the residue is sludge providing little applicability. According to the legislation in some Brazilian states, this sludge cannot be used as agricultural fertilizer, for example”, laments Luiz Antonio Daniel, who is one of the coordinators from the partnership and professor of the Hydraulic and Sanitation Department at the Engineering School of the São Carlos campus of São Paulo University (EESC-USP). “The sledge, then ends up in sanitation landfills, which means, a considerable expense is necessary to get rid of it.” In the tests performed by the research team, the Chlorella algae take advantage of the nitrogen and phosphorus present in the sewage, as well as the micronutrients in human waste and then they reproduce, forming biomass that is essential for fertilization. The next step in the studies is to make the entire process optimized, so that is operates on an industrial scale. This research depends on a partnership with the Netherlands Organization for Scientific Research (NWO). “For example, there is no sunshine during the entire year in the Netherlands, as here in Brazil, neither intense heat, as cold weather hinders alga growth. It is necessary to make some adjustments in order to achieve a higher scale”, Daniel explains. Field tests are being performed at the Sewage Treatment Station in the city of São Carlos, in the instate region of São Paulo.
Another interesting example for using microalgae was discovered by scientists from South Africa who were seeking a solution for millions of tons of coal dust discarded yearly in nature. The researchers at Nelson Mandela Metropolitan University discovered that the microalgae can be mixed with coal. “When we mix coal dust and alga biomass, the algae will adhere to the surface of the coal and bond with the powder particles”, describes Ben Zeelie, who is the project coordinator. The byproduct is a “coal-alga” compound, named and patented as Coalgae, which can be used as a substitute in applications requiring coal or as biofuel.
Zanzibar, in Tanzania, is the third largest producer of macroalgae in the world after the Philippines and Indonesia. The majority of the annual alga production, 15,000 tons, is exported to Denmark, the USA, China, France, and Belgium. It is estimated that 28 thousand people, mainly women, are engaged in the seaweed crop. Two types of seaweeds are cultivated in the region: cottonji featuring a higher gelatinous content and, therefore, it is more expensive and the spinosium type, whereas the gelatinous content is lower and therefore less expensive. The government of Zanzibar is in the process of setting up a plant for producing gelatin and adding more value than by just exporting the raw material. In March 2018 the United Nations Industrial Development Organization (UNIDO) supplied about US$ 80,000 to the producers in equipment for harvesting and processing the seaweed from the region as part of a cooperation treaty with the government of Tanzania.
Another example of how macroalgae can add value to the economy came from a company that decided to invest in bio-fertilizer made from macroalga extracts in Brazil. “Since, this product has already been proven to provide 10 to 15% more yield to crops, such as soybeans, maize(corn), beans, bananas, and grapes”, prides himself Gregori Vieira, owner of Dimiagro, a company responsible for funding research. This natural additive fosters the growth of roots and other length-increasing parts of the plant by facilitating the presence of specific vegetal hormones. Thus, the plant profits more from the soil and can withstand environmental hardships. This extract is already especially used in perennial crops, but also in annual crops in Europe and the United States. Countless research study results performed in Brazil have proven efficacy from utilizing some selected alga extracts.
As the commercially macroalga extract used in Brazil is obtained in Ireland, where its waters are very cold, then the Brazilian research studies are performed to obtain alga extracts and cyanobacteria from the same Brazilian biodiversity, which means from the Country itself. “We will produce them in competitive production systems and thereby generate employment in the Region. For example, they can be produced in bio-reactors, in order to maximize space utilization and facilitate the reuse of water and waste products”, highlights César Miranda, researcher from Embrapa “Agroenergia” (Agro-energy), and who is responsible for the project.
The spirulina or “blue gold” is a microalga considered by specialist as the second most nutritious food compared to breastmilk, and thus, it can minimize undernourishment in Africa and other poverty-stricken regions of the world. In the 1960s, Jean Léonard, a Belgian botanist noticed that a Chad tribe enjoyed better health than others, as its members ate spirulina growing in the lake water. In 1974, the UN designated this as the “food of the future”, due to its high concentration of proteins (65%), iron, beta-carotene, and vitamins B12, E, and K.
It is sold in pill or powder format in wealthy countries and then it is added to salads or juices. The natural habitat of spirulina is slightly saline water lakes in tropical countries – whereas it can be reproduced artificially. Around a total of 5,000 tons are produced yearly, 400 of them in the Chad lakes, according to the Food and Agriculture Organization of the United Nations (FAO). China and the North American state of California are the main producers in the world.
In southern Angola, FAO performed a pilot project with the local government to encourage the production of spirulina, as a manner to fee the most vulnerable population of that region and diversify the economy. Due to the 250 thousand dollars deployed in the product funding, a project for growing microalgae, it has already produced at least 1.2 tons of spirulina in less than a year.