Microalgae-based bioinput can reduce dependence on agricultural fertilizers

A partnership between the São Paulo state startup BiotecBlue and the São José dos Campos campus of the Federal University of São Paulo (UNIFESP) is transforming tilapia and beer production waste into an innovative bioinput. This initiative promises to reduce Brazil’s dependence on fertilizer imports, lower costs for farmers, and promote a circular economy in rural areas.

Supported by FAPESP’s Innovative Research in Small Businesses Program (PIPE), the project uses treated effluents from breweries, tilapia, and shrimp, which would otherwise be disposed of improperly, to cultivate microalgae. The biomass is then harvested and concentrated to create a biostimulant that provides farmers with an affordable alternative to conventional chemical fertilizers.

Small craft beer producers often dispose of manufacturing waste directly in the sewer system. The same occurs with leftover tilapia and shrimp farming waste. Without treatment, this waste reaches rivers, carrying a load of nutrients capable of disrupting aquatic ecosystems.

This waste is rich in nitrogen, phosphorus, and carbohydrates, which are essential elements for microalgae growth. When dumped unchecked, the waste causes eutrophication, a process that generates uncontrolled algae growth and alters water color. Eutrophication can also lead to fish deaths due to a lack of oxygen.

However, if cultivated in a controlled manner, these same microalgae can be used as agricultural bio-inputs. Danielle Maass, a chemical engineer and professor at the São José dos Campos campus of UNIFESP, is pursuing this strategy in collaboration with BiotecBlue.

From fish farming to breweries

Initially, the team used waste from intensive shrimp and tilapia production. The results were encouraging. Not only did the microalgae grow healthily, but they also had higher nutritional concentrations than those obtained in synthetic culture media. “The water left over after cultivation has few nutrients, meaning it can be returned to the river or used in a production process,” Maass points out.

Despite this initial success, the closure of the supplier fish farm highlighted the fragility of relying on a single source. The solution came from a rapidly expanding sector: brewing.

“We tested beer production waste and the material had nutritional characteristics similar to those of aquaculture, such as carbon, nitrogen, and phosphorus,” says the researcher. In addition to its effectiveness, it is also easier to transport. “Today there are many small and medium-sized craft breweries. It’s much easier to obtain this waste than fish farming waste,” she adds.

One of the project’s unique features is that it was validated using real waste rather than simulated waste in a laboratory. “Many researchers try to emulate waste with compounds of interest in the correct quantities, but it’s not the same thing. Real waste has a huge variety of compounds that can either help or hinder the process,” the engineer explains.

Carbon fixation

The microalgae resulting from the process are rich in protein and beta-carotene, a natural antioxidant. “They can even be reinserted into the production chain as a food supplement for fish and shrimp,” says Maass. In the case of crustaceans, beta-carotene intensifies their reddish color, which is valued by the market.

Another significant environmental benefit is carbon fixation. As they grow, microalgae perform photosynthesis and capture carbon dioxide (CO?) from the atmosphere. This opens the door to the carbon credit market, a central topic of global discussions such as COP30, which was held in the Brazilian city of Belém, Pará state, at the end of 2025.

The project has been in the scaling phase since 2024. The team is currently designing equipment for a 100-liter pilot scale. The product is undergoing testing on corn, banana, vegetable, and coffee crops in the states of São Paulo and Minas Gerais.

According to Maass, there has been improvement in leaf development and soil health. “We tested enzymes that help fix phosphorus and nitrogen in the soil, making it healthy again,” she says.

Economic viability

Economic viability is one of the pillars of BiotecBlue. “With a small dose, we have a big effect, and based on the gross cost survey we did, the product is indeed cheaper,” says Maass. According to the National Association for Fertilizer Distribution (ANDA), Brazil spends approximately USD 25 billion annually to import more than 85% of the fertilizers consumed domestically. China and Russia are the main suppliers, and recent geopolitical conflicts have dramatically affected the prices and availability of these non-renewable inputs.

According to the Brazilian Agricultural Research Corporation (EMBRAPA), fertilizers account for up to 50% of corn production costs and 40% of soybean production costs. The National Fertilizer Plan aims to reduce this dependence by 50% by 2050. Microalgae bioinputs align with this goal and are expected to launch in 2026.

Cultural barriers

Despite the benefits, the project still faces cultural resistance. “There’s a lack of knowledge about the environmental impacts of chemicals,” Maass observes, noting that younger producers tend to be more receptive to a sustainable transition. On the other side of the chain, brewers and fish farmers are often surprised to learn that their waste has commercial value.

Maass, an expert in biotechnological processes and the recovery of critical metals from electronic waste and mining, argues that industrial waste should be viewed as a raw material. “Biotechnological processes take a little longer to develop, but once ready, they’re much more sustainable than physical or chemical processes,” she points out.

The project has a team of PhDs and undergraduate research students and plans to expand its services from small rural producers to large ones. According to reports from Markets and Markets, the global blue biotechnology market is expected to grow from USD 14.5 billion in 2024 to USD 29.5 billion by 2032, which would consolidate the transformation of waste into a promise of a greener, more independent agriculture.