top of page

Teaching Resources

Civilisation and Culture

Have you noticed how statues or buildings darken with time? Those marks may be the work of microbes—bacteria, fungi, and algae—that settle on stone, wood, or even plastic, creating what’s known as microbial patina. These invisible artists stain, crack, and color surfaces, sometimes protecting them and sometimes causing decay. In humid, salty places like Venice, their growth can turn walls green or black, while elsewhere, conservators even use “good” microbes to clean ancient art. Artists, too, have embraced these living pigments, collaborating with bacteria to create bio-art. Every artistic surface—canvas, clay, glass, or metal—becomes a new ecosystem where microbes quietly thrive. Thus, art and nature intertwine: humans shape materials, and microbes, in turn, reshape them. The result is a shared masterpiece—one written in rust, biofilm, and time itself.

Microbial Patina

Rachel: what is that black stain on the statue?

Read More

Rachel Armstrong

Imagine a “living paint” so slow-growing it takes millennia to form—a dark, glossy layer called rock varnish, created by microbes feeding on manganese carried by wind and rain. Tough as armor yet thin as a coin, this natural coating became the perfect canvas for ancient artists. Across deserts and cliffs worldwide, early humans carved petroglyphs into these microbial surfaces, leaving behind spirals, animals, and scenes older than the pyramids. Formed by bacteria and fungi over thousands of years, rock varnish stands as a bridge between geology, biology, and human history—an enduring record of both nature’s artistry and humanity’s imagination.

Prehistoric art

If varnish is something we paint on wood, how can rocks have varnish? Who paints it?

Read More

Gilreath Far Western Anthropological Research Group

Before plant fibres are used in such applications, the process of retting is usually employed to separate fibre bundles from other plant material. Retting is a biological process, involving microbial secreted enzymes to remove non-cellulosic materials attached to the fibre bundle, and yielding detached cellulosic fibres. The use of the plant fibres helps meet many of Sustainable Development Goals (SDGs).

Binding and construction materials: Plant Fibre Retting

Dad: why doesn’t everyone build their house with wood and leaves like us? It is so much more sustainable!

Read More

Microorganisms, disease and water – from a horror story to a perfect solution

Wastewater treatment

Sis: what happens to all that smelly stuff we flush down the lav?

Read More

Photo by Marcin Jozwiak from Pexels

Philosophy is undoubtedly by humans, for humans, and about humans. It is deep and abstract, while microbes are often viewed as mindless pieces of biological matter. So, how do these two seemingly unrelated subjects intersect? And why would anyone want to philosophize about microbes and the science that studies them—microbiology? To explore these questions, let’s break things down. First, we need to consider the nature of philosophy and its purpose. Next, we should take a broader look at microbes and microbiology, and—since we tend to view the world through a human-centric lens—focus on the relationship between microbes and ourselves. Once we've done that, we can move on to a third step: connecting these two realms in a way that makes the 'philosophy of microbiology' seem like something truly worth contemplating.

Thinking Philosophically About Microbiology

Mum: what am I if I am only 50% human and the rest is microbial?

Read More

Copyright: Marcus DeSieno

Sir William Osler highlighted that infectious diseases like typhoid, malaria, cholera, and dysentery have caused more wartime deaths than weapons. Florence Nightingale, the founder of modern nursing, significantly reduced these deaths during the Crimean War by improving hospital sanitation, curbing the spread of deadly infections. Her work, supported by her statistical methods like the Rose Diagram, showed that infections were the primary cause of death in wartime hospitals. Historically, infections have shaped the outcomes of wars, as seen in the European conquest of the Aztecs and Incas, where smallpox devastated indigenous populations. Crowded military conditions, such as those during the 1918-1919 influenza pandemic in World War I, have fueled the spread of diseases, often killing more soldiers than combat. Despite advances in sanitation, vaccines, and antibiotics, microbial threats persist, with antibiotic-resistant bacteria and vaccine-preventable diseases still endangering soldiers and civilians, especially in disrupted war zones.

Infections and wars

Mom, who was Florence Nightingale and why was she called the “Angel of Crimea”?

Read More

Infectious diseases have always been a part of life on Earth, evolving as microbes adapted to new hosts. Homo sapiens appeared around 300,000 years ago, and the shift to agriculture 10,000 years ago drastically changed disease spread. Permanent settlements and close contact with animals increased the likelihood of diseases jumping from animals to humans. Infectious diseases are often described as endemic, epidemic, or pandemic. Endemic diseases, like malaria in sub-Saharan Africa, persist in a region. Epidemics are localized outbreaks, such as recent measles cases in Europe. Pandemics, like COVID-19, spread globally, causing widespread disruption and death, significantly shaping history, economies, and societies.

Plagues that decimated civilisations: pandemics as past, current and future threats to humanity

Read More

Detail of ‘The Triumph of Death’ by Pieter Bruegel the Elder, c. 1562 (Museo del Prado, Madrid)

In a world in which the gut microbiome and its relationship with human health is a hot topic, fermented foods are becoming increasingly popular, with consumption increasing 149% in 2018 according to FORBES. But fermented foods are not just associated with a healthier gut: fermentation can also create flavors that cannot be accomplished any other way. According to the Rockefeller University, “fermentation is a culinary exploitation of a microbial system”. Even more, fermented foods are rich in nutrients, have a longer shelf-life, and display unique textures and organoleptic properties. Nevertheless, fermented foods must be manufactured and stored in a controlled environment to ensure safety, quality and constant organoleptic properties in the final product. Fermented foods are associated with multiple sustainable development goals.

Fermented foods

How can bacteria turn something liquid, like milk, into something solid, like yogurt?

Read More

Photo by Gustavo Fring (Pexels)

Indigo has been one of humankind’s favourite dyes since prehistoric times, and remains today one of the most important textile dyes, largely due to the enduring popularity of denim jeans. Indigo is insoluble in water, and to be used as a dye it has to be chemically reduced to a soluble, colourless chemical form, which is called indigo white. For the past hundred years the dyeing industry has relied on the reducing power of alkaline sodium dithionite, (also known as sodium hydrosulphite) but this results in large quantities of sulphur waste to be disposed of. Before the introduction of chemical methods, indigo was dissolved in a fermentation vat, where anaerobic bacteria reduced the indigo. This method is still used on a small scale commercially in India. Harnessing the power of bacteria to dissolve indigo industry-wide would help lessen the environmental impact of producing blue jeans.

Using bacteria to dissolve indigo for dyeing

Sir: I’ve heard that dyeing blue jeans causes a lot of chemical pollution. How could this be lowered?

Read More

Image: by Louise Cornelissen, via Pexels.com

Bandera de Costa Rica

Institutions

Logo Centro Nacional de Innovaciones Biotecnológicas (CENIBiot)
Logo Universidad de Costa Rica (UCR)
Logo Centro Nacional de Alta Tecnología (CeNAT)
Logo Escuela de Química UCR
Logo Centro de Investigación en Productos Naturales (CIPRONA)

Email

max.chavarria@ucr.ac.cr

Telephone

+506 2511 2270       (CIPRONA)
+506 2519 5871       (CENIBiot-CeNAT-CONARE)

  • Instagram
bottom of page