MICROCAP, an algae-based oxygen generator that removes CO₂ and Purifies Indoor Air 

A lecturer from the Department of Chemical Technology, Faculty of Science, Chulalongkorn University, has invented the MICROCAP air purifier, which uses photosynthetic algae to absorb carbon dioxide and produce 20 times more oxygen than trees. 

Trees are a source of oxygen production can purify the air. It is lamentable, however, that forested areas and the number of trees worldwide are reducing. Moreover, the lifestyle of city people and the modern industrial world have also become factors in causing air pollution, whether from exhaust fumes from engines, smoke from industrial factories, incinerators, etc. These can all affect the health of life on the planet. 

Increasing and restoring forest areas while also promoting tree planting are therefore essential. However, in an urban context, there may be space limitations. Assistant Professor Dr. Pichaya In-na, a lecturer in the Department of Chemical Technology, Faculty of Science, Chulalongkorn University, has therefore attempted to solve this problem by inventing “MICROCAP”, an innovation that uses the power of microalgae to capture carbon dioxide (CO₂) to produce oxygen (O₂). 

“The public is beginning to pay attention to Carbon Neutrality¹, and carbon dioxide capture is a global issue. For this reason, I aspired to become an expert in this field. However, I wanted to employ a groundbreaking technology that mimics nature and does not harm the environment. That technology is the microalgae technology,” said Asst. Prof. Dr. Pichaya, who also added that the microalgae in the MICROCAP act like indoor plants, capturing carbon dioxide and converting it into oxygen 20 times more than the Chamchuri Tree! 

“Many of us are concerned about PM 2.5 dust, but we should not overlook carbon dioxide, which is just as dangerous. When we exhale, we exhale carbon dioxide. If indoor air isn’t ventilated, carbon dioxide builds up, directly impacting health, particularly the brain’s decision-making system. Prolonged exposure, such as in a classroom, can cause drowsiness, reduced attention span, and headaches. Long-term exposure can even lead to lung cancer.” 

What are microalgae? 

According to Asst. Prof. Dr. Pichaya, microalgae are microbial cells that can photosynthesize similarly to plants but are not classified as plants. They have structures similar to bacteria, making them a class between the Plant Kingdom and the Protista Kingdom. 

“Microalgae are found in a wide variety of environments. Typically, the algae we can see are not microalgae, but are known as macroalgae or seaweed. Microalgae, or cyanobacteria, are another subset of algae, which can only be visible using a microscope,” Asst. Prof. Dr. Pichaya further explained, citing an example of cyanobacteria many may have heard of—Spirulina. 

“Microalgae are 10–50 times more efficient at photosynthesis than plants, or even 100 times more efficient in terms of biomass production in some species. This property is common knowledge in algal biotechnology field, but few researchers in Thailand have applied it to the problem of capturing indoor CO₂ and converting it into clean air.” 

MICROCAP: Uniqueness and how does it work? 

Intrigued by the unique properties of microalgae from the time she was doing her doctoral studies till present (almost 10 years), Asst. Prof. Dr. Pichaya sought ways to utilize microalgae technology. Ultimately, she succeeded in producing MICROCAP (short for “MICRO” from microalgae and “CAP” for capture). 

She explained the operation of the MICROCAP, or air purifier, saying, “MICROCAP draws indoor air into the reactor, which contains microalgal cells. The cells then operate using photosynthesis by absorbing CO₂ and in turn releasing O₂ as a by-product. Our main secret is the nutrient recipe that we optimized to increase the CO₂ absorption rates.” 

The microalgae placed in the MICROCAP reactor must first undergo what Asst. Prof. Dr. Pichaya calls a “torture process” as a metaphor. This involves the use of chemicals or modifying the nutrient formula to achieve the desired function, which in this case is to optimize CO₂ removal efficiency. 

“The microalgae are grown in the lab for approximately 1–2 weeks. After that, the microalgal cells, along with the researched nutrient formula, are placed in the MICROCAP, allowing them to reach their peak growth stage and capture the maximum amount of CO₂.” 

Asst. Prof. Dr. Pichaya stated that the MICROCAP is a biological nature-based process machine. Therefore, once installed, it takes around 1–3 days for the microalgae to start working and adapting to their environment and for the MICROCAP to be ready to operate. They will then produce O₂ for approximately a month, based on the microalgae’s life cycle. For this reason, the MICROCAP is available on a monthly rental basis, as the microalgae must be refreshed, and the MICROCAP will be cleaned every month. 

A mini-sized MICROCAP is currently in the works for small spaces. 

The MICROCAP prototype measures 60x60x150 cm (100 L capacity). It is designed to cover areas of approximately 400 square meters, such as schools, offices, and shopping malls. The prototype MICROCAP is currently located in the Faculty of Science Library, Chulalongkorn University. 

“After launching this innovation, we received a lot of interest. Many people asked about air purifiers that could be used in small spaces. We are currently considering that if we were to make a small machine, what business models would best suit our target customers.” 

Regarding the plans she has for the future, Asst. Prof. Dr. Pichaya is exploring opportunities to collaborate with property owners and designing two possible approaches: investing in her research projects and looking for investors for Algae Deep Tech Co., Ltd., where she serves as Chief Technology Officer (CTO). 

From Research to Clean Air Products 

Asst. Prof. Dr. Pichaya revealed the secret behind her success as a research and product developer: “Product development requires a multi-faceted approach; the focus should not only be just research but also business. At first, I had no such business knowledge and had to learn it by myself. Product design cannot be done alone; a strong support team is crucial, both in terms of research and business experts. A multidisciplinary team consisting of various members from different backgrounds must work together to create a successful product.” 

Regarding research, this project received support from several sources, including funding from the Bio-Circular-Green Economy Technology & Engineering Center (BCGeTEC) from the Faculty of Engineering, Chulalongkorn University; the Research Unit of Sustainable Algal Cultivation and Applications (RU SACAS); and the Technology and Innovation Entrepreneurship Development Fund from the Ministry of Higher Education, Science, Research and Innovation (TED Fund) for research on microalgae technology from the Ministry of Higher Education, Science, Research and Innovation. 

In terms of business, Asst. Prof. Dr. Pichaya has received support from the CU Innovation Hub, CU Enterprise, and Chulalongkorn University Institute of Integrated Innovation (CSII), providing knowledge on product development. The Chula spin-off project from the Faculty of Science, Chulalongkorn University, has also helped establish Algae Deep Tech Co., Ltd., a startup focused on applying algal biotechnology to provide nature-based solutions to solve urban environmental problems. 

“I conducted research on microalgae technology for CO₂ capture and discovered that nature can provide us with many answers. I wanted to develop this technology into a product inspired by nature and bring it to the market to truly help society by improving air quality,” she said. 

Asst. Prof. Dr. Pichaya recalled her childhood dream: “I have always wanted to be an innovator since I was a child and wanted to produce something of my own that truly addresses social needs.” 

Today, Asst. Prof. Dr Pichaya has been able to achieve her dream of becoming an innovator, in which her invention, the “MICROCAP air generator,” provides a real sustainable solution to the pollution problem in today’s urban society. 

Those interested in the MICROCAP can pre-order them from Algae Deep Tech Co., Ltd.’s website. Production takes approximately one month. The company offers a monthly subscription rental service starting at 5,000 baht per unit per month (for 50L capacity). The MICROCAP can be installed indoors and includes lifetime maintenance at no additional cost. Contact us at 098-825-2390 or visit www.algaedeeptech.com. 

Notes:

1. Carbon neutrality refers to the offset of carbon dioxide (CO₂) equivalent to the amount of CO₂ emitted.
2. The Protista Kingdom refers to single- or multicellular organisms that have not yet developed into tissues. Information from https://ngthai.com/science/45804/protista/ 
3. Blue protein derived from algae can be used in the cosmetics industry as a natural colorant instead of synthetic dyes. 

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