Red: How Microbes Are Redefining the Colour of Passion
Red: The Hue of Emotion and Tradition
Red is one of the most powerful colours in human culture and emotion. It is the colour of passion and love, the warmth of a setting sun, and the intensity of a beating heart. Red demands attention, sparks excitement, and inspires action.
Across the world, red carries diverse meanings. In China, it symbolizes prosperity and happiness. In India, it represents purity and is worn by brides. In the West, it stands for love. But beyond symbolism, have you ever wondered where red comes from?
Red is everywhere—in our clothes, food, cosmetics, and art. But not all reds are created equal. Let‘s explore the three primary sources of red pigments: fossil fuels, plants, and microbes.
Fossil Fuel-Based Red: The Cost of Vibrancy
Most red dyes, like azo and anthraquinone dyes, are made from petrochemicals. These dyes originate from crude oil and natural gas derivatives. For example:
Azo dyes (like Allura Red AC, used in candy and drinks) are made by treating aniline (derived from benzene) with nitrous acid to form a diazonium salt, which is then coupled with aromatic compounds to create red pigments.
Anthraquinone dyes (like Reactive Red 195, used in textiles) are made by modifying anthraquinone (derived from benzene or naphthalene) to create stable red hues.
These dyes are bright, long-lasting, and cost-effective. However, their production involves toxic chemicals and generates hazardous wastewater that when improperly disposed of (a problem that persists) affects the health of nearby communities and wildlife. Some have even been linked to environmental pollution and health concerns, leading to a growing demand for sustainable alternatives.
Plant-Based Red: Nature‘s Palette
For centuries, red dyes came from natural sources like madder root and cochineal insects.
Madder root is dried, crushed and processed to extract alizarin, a deep red pigment used for textiles.
Cochineal insects are dried and processed to produce carmine, a brilliant red dye used in food and cosmetics.
While plant-based dyes are biodegradable and renewable, they have drawbacks. Extracting them requires large amounts of raw materials, and they often fade over time. Additionally, harvesting cochineal insects raises ethical concerns for some consumers. These limitations have fuelled the search for a better solution—one that combines nature‘s brilliance with sustainability.
Microbe-Based Red: The Future of Colour
Microbes—bacteria, fungi, and algae—are nature’s microscopic artists, producing vibrant red pigments in ways that are both innovative and sustainable. Here’s how they do it:
Bacteria (e.g., Serratia marcescens) produce prodigiosin, a red pigment that may help protect them from UV radiation and oxidative stress while having a role in antimicrobial defense. They create it naturally from simple feedstocks like glucose and amino acids.
Fungi (e.g., Fusarium graminearum) generate rubrofusarin, a red-orange pigment, using enzymes that convert carbohydrates into colour.
Algae (e.g., Porphyridium cruentum) synthesize phycoerythrin, a red pigment that optimizes light absorption for photosynthesis.
What makes microbial dyes revolutionary? They can be produced using renewable feedstocks such as agricultural waste, industrial byproducts, or even CO₂ emissions. This creates a circular economy where waste is transformed into colour, eliminating the environmental impact of fossil fuels and the resource intensity of plant-based dyes.
Living in a Microbial Red World: What Does It Feel Like?
Imagine a world where the reds in our life—our clothes, our food, our home—are all created by microbes. How would that feel?
Wearing microbial red: Soft, sustainable fabrics dyed with bacterial or fungal pigments, free from harmful chemicals
Eating microbial red: Safe and natural food colorants derived from algae or fungi
Living in microbial red: Eco-friendly paints that bring warmth and energy to our space without the harmful fumes
Microbial pigments allow us to enjoy the beauty of red while protecting our planet. They remind us that even the smallest organisms can create big change.
A New Era of Colour
Red is more than just a colour – it is an emotion, a symbol, a story. By harnessing the power of microbes, we can honour this story in a sustainable and innovative way. Microbial reds are not only vibrant and beautiful but also a testament to the potential of nature’s tiny artists.