Bacteria, fungi, and algae: tools for architects

I peered down a microscope lens and noticed minature creatures, rod-shaped, elegantly floating around in solution, like a lily on a pond. How these small creatures, known as bacteria, could survive above and within plant leaves baffled me.

I studied microbiology for several years, completing a Doctor of Philosophy in microbiology at Victoria University of Wellington in 2022. My research was focused on understanding how the plant pathogen Pseduomonas syringae pv. actinidiae infects the kiwifruit leaf. The interaction between bacteria, leaves and the environment is just one example of how the natural world is interconnected.

Biomimicry in architecture

I was intrigued by the world of living organisms, particularly microorganisms, and wondered whether they could play a role in sustainable architecture. I first heard of the term biomimicry in the context of architecture when I attended a lecture given by architect Professor Klaus Klaas Loenhart at Victoria University of Wellington in the School of Architecture in 2019. Loenhart described reimagining the built environment with forests, gardens, and vegetation. Seeing nature as a codesigner, Loenhart’s work explores ways to make urban spaces live and breathe by mimicking the performance of nature. Leonhart’s Austrian Pavilion exhibit at the 2015 Expo World Fair in Milan was a reflection of this. The pavilion incorporated elements of the Austrian forest to cool down hot climatic conditions, whilst producing oxygen. As such, the cooling mechanism in plants has been deemed a replacement for artificial air-conditioning. Loehnart acknowledges that the forest is not alone. The plant microbiome is also with us, every day and everywhere. It is something that we should feel connected with. Being a researcher in microbiology, I was touched by Loenhart’s eco-vision.

The biomimicry toolbox

The world is drowning in carbon dioxide emissions, with buildings, construction, and materials all contributing to the problem. The solution to our mess is already here and is inescapable. Using what Loenhart described, mimicking the natural world is how we can create better urban environments. Embracing this concept, I view the structure and function of bacteria, fungi, and algae as being with us, in our buildings, our streetlights, and our living spaces.

We are immersed in an environment with other living biomes. In most cases, this might not be visible to the naked eye. Bacteria, fungi, and algae seem to be underappreciated when it comes to architectural designs. They have profound roles in life, including health, plant growth, food production, antibiotic discovery, disease, and climate change, to name a few. Architecture could be their new frontier.

Currently, the world’s infrastructure is heavily reliant on non-renewable sources such as fossil fuels, which contribute to carbon dioxide emissions. Materials such as bricks and concrete are the building blocks of many houses and buildings. Producing these products requires substantial energy, typically obtained from burning coal. The heating, cooling, and lighting are run by electricity generated from non-renewable sources. Collectively, these current actions are stacking up and increasing our carbon footprint.

Bioluminescence

Every night, streetlights, lamps, signs, parks, and billboards light up. What if natural processes could make them glow like a Jedi’s lightsaber? Some species of algae (e.g. Pyrocystis fusiformis), bacteria (e.g., Vibrio fischeri), and fungal mycelia (e.g., Panellus stipticus), can employ a natural reaction to produce bioluminescence. These species have an internal clock, also known as a circadian rhythm, that enables them to be more active at night, so they produce more light. By using microbes as an alternative, waste arising from metals and industrial manufacturing associated with artificial light generation is eliminated. Only nutrients to maintain their growth are needed. From an artistic point of view, incorporating bioluminescence is an appreciation of nature’s beauty.

Microalgae

Every day our world is still powered by unclean sources. What if our energy could be sourced from natural renewable processes? Microalgae could offer renewable energy and even clean the air by absorbing carbon dioxide generated by adjacent freeways or traffic. Microalgae are microscopic organisms that live by soaking up the sun, carbon dioxide, and water or wastewater to breathe out oxygen and energy in the form of hydrogen, a natural chemical process called photosynthesis. What is advantageous about this process in microalgae is that it provides energy, oxygen, acts as a carbon sink, and can utilise wastewater, overall creating a closed-loop system. The application of microalgae in a built environment is practical. At the international building exhibition in Hamburg in 2013, "SolarLeaf" by the design company Arup used algae- filled tubes on a building façade. A single-step algae oil extraction biofuel production process is currently in use.

Fungi

Every day we eat, sleep, play and work under a roof. What if building materials could be made from waste materials or even biodegrade when desired? The mushroom is a fungus that has a hidden profile. Under piles of leaves and the shady sun, they thrive on decomposed organic matter. Their long minuscule hyphae crawl from below the ground like branches to network with the forest, feeding energy into the forest as if it were Twitter, connecting humans to humans. The microscopic branch-like structure is known as mycelium. Exploiting this feature, mycelium bricks are made from just farm waste and the culture of fungus that is grown within a brick-shaped cast. The bricks are strong, light, and fire-resistant, making them suitable for insulation material, interior walls, and façade cladding. Above that, the production process is less energy-consuming than cement. Mycelium bricks are easy to grow and are fully biodegradable when exposed to the right microorganisms. The promising potential of mycelium towers is possible as "Hy-Fi" by architect David Benjamin was exhibited at the Museum of Modern Art, New York, in 2014.

Preservation of historic buildings

Moreover, what if building materials involved less energy to construct? Rocks may seem like an unattractive environment to live in, being dry and rock solid. But for the bacterium Sporosarcina pasteurii this is not a problem. Microbial-induced calcite precipitation has been slowly creating rock formations on Earth for billions of years. This natural process uses bacteria such as Sporosarcina pasteurii to glue sand, calcium, and urea together to form stone. The benefit of this process is that it can occur at room temperature, thereby reducing the need for heat in the biomineralization process. Companies like BioBrick have been harnessing this natural process to build bricks.

Some days, buildings get demolished or need to be repaired. What if we could increase the lifespan of our building materials or even preserve our historic buildings? Traditional concrete erodes and weakens over time, allowing moisture to penetrate through cracks and rust the reinforcing materials within. Traditional building materials are ubiquitous, expensive to maintain, and create a tremendous carbon footprint through the burning of limestone to obtain calcium oxide, which is an essential component of cement. The company BioConcrete aims to extend the lifetime of traditional concrete by using Sporosarcina pasteurii to fill in any fissures through the secretion of limestone in the material. The crack is sealed before any unwanted moisture or air can enter the concrete. This natural process would lower the cost of remediation work, delay rebuilding maintenance, as well as reduce the demand for cement. I call this one of nature’s self-healing remedies.

Healthy environments

All day and every day, we breathe in and out the air in the environment. What if microbial diversity could improve human living environments and the overall quality of health? Humans are not separate entities from those living around us. Our spaces and our bodies are saturated with microbial diversity. It makes up every human identity. Most of them are healthy microbes. Beneficial but also diverse microorganisms in the built environment may promote better health and bring about a sense of connection. Another one of David Benjamin’s installations, "Alive", was a probiotic pavilion exhibited at the Biennale Architettura Venice 2021. The pavilion was made from sponges from luffa (a sponge-like gourd from the cucumber family), designed to house void pockets for beneficial microorganisms to flourish. A healthy connection with the living world around us is like an emotional attachment. Humans yearn for that.

Future of architectural design

The opportunity for sustainable architecture is right in front of us. Bacteria, algae, and fungi are valuable sources of inspiration for greater eco-design practices. Architecture and infrastructure should be a copy and paste of nature’s great inventions, such as the natural processes found in self-healing bricks made by bacteria, renewable energy and oxygen from algae, bioluminescence by bacteria, and materials made from fungi. Creating a better future means establishing an interconnected relationship between humans, living spaces, and the natural world. The best tools may not always be visible or heard.