As a bioengineer, Joris (founder of YOKUU), runs his own lab studies to discover how exactly bacteria can improve the health of our homes. 

In this particular study, from late 2020, he wanted to find out if the beneficial bacteria in YOKUU's cleaning pearls could grow using indoor dust as their only food source, survive and multiply in carpet fibres, and ultimately outcompete harmful bacteria and fungi over time.

Here’s how we tested it, and what we discovered.

Step 1: Build a mini carpet ecosystem

We collected real indoor dust from office buildings in Belgium (yes, it was kind of gross), then sieved and sorted it to create a consistent test material. This dust was applied to clean carpet squares (each just 25cm² in size) to mimic a realistic indoor setting.

These “carpet microcosms” were split into three groups:

  • Clean carpet only
  • Carpet + dust
  • Carpet + dust + YOKUU's probiotic blend (aka MBCP: Microbial-based cleaning product)

The carpets were incubated at 30°C and high humidity for 30 days.

We then analysed each sample using traditional microbiology and metagenomic sequencing (a way to map all the microbes present using DNA).

Step 2: What we found

Our bacteria grew, and thrived

They successfully used carpet dust as their only source of carbon. Even under competition with existing microbes, they held their ground and maintained a stable population (around 10⁹ CFU/m²).

They shifted the microbiome

In untreated carpets, the dominant microbes were human-associated (from skin and breath), plus a large presence of Aspergillaceae - a common indoor fungus. In contrast, MBCP-treated carpets were rich in Bacillaceae and showed no trace of fungal growth.

They may help trap dust

An unexpected observation: our bacteria appeared to act as a flocculant, clumping fine dust together. That could mean less dust floating in the air, a potential bonus for indoor air quality.

How we measured it

To track the effects of our probiotics, we ran a mix of microbiology and DNA-based tests:

  • We developed our own method to extract microbes from deep inside carpet fibres, with over 85% recovery rate.
  • We tested how our bacteria grew in liquid cultures using only carpet dust as food.
  • We extracted and sequenced microbial DNA to analyse how the bacterial population changed over time.
  • We compared different test conditions: sterile vs. non-sterile dust, and treated vs. untreated carpet.

Everything was tested at the start (Day 0) and again after 30 days in warm, humid conditions.

What this tells us

  • Our bacteria grew on dust alone.
  • They survived in carpets and stayed stable.
  • They shifted the microbiome - no fungi, less unwanted bacteria.
  • Without probiotics, fungi and human bacteria took over.
  • Bonus: our bacteria helped clump dust, meaning less floating in the air.

  • YOKUU'S CARPET MICROBIOME STUDY

    YOKUU'S CARPET MICROBIOME STUDY

    As a bioengineer, Joris (founder of YOKUU), runs his own lab studies to discover how exactly bacteria can improve the health of our homes.  In this particular study, from late...

    YOKUU'S CARPET MICROBIOME STUDY

    As a bioengineer, Joris (founder of YOKUU), runs his own lab studies to discover how exactly bacteria can improve the health of our homes.  In this particular study, from late...

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    WHY YOUR LAUNDRY STILL SMELLS (AND HOW TO FIX I...

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    WHY YOUR LAUNDRY STILL SMELLS (AND HOW TO FIX I...

    You wash your clothes. You dry them. But they still smell kind of… off? That lingering odour actually has a name: permastink. And no, it’s not your fault.

  • YOKUU IS NOW A CERTIFIED B CORPORATION™

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    In the world of cleaning, we’ve always done things a little differently. Now it’s official: YOKUU is a Certified B Corp™. This means we meet some of the highest standards...

    YOKUU IS NOW A CERTIFIED B CORPORATION™

    In the world of cleaning, we’ve always done things a little differently. Now it’s official: YOKUU is a Certified B Corp™. This means we meet some of the highest standards...

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