Guts and glory

Local biotech start-up Biomine is putting a new spin on the old alchemist’s trick of turning lead into gold — it’s substituting faeces for lead.

The Cape Town company says it is the first in South Africa to focus on exploiting the rich commercial potential of the gut microbiome, the trillions-strong empire of microbes — mainly bacteria, viruses and fungi — in the human intestine. It does so by analysing stool samples.

“We want to have the biggest, most diverse African microbiome database, that’s the vision … the big moonshot,” Biomine chief technology officer Diego Castillo, who co-founded the company with CEO Vaughn Barendsen three years ago, tells the FM. “R&D is a super important part of our business.”

In recent years the gut microbiome has taken centre stage in the global health and wellness industry — it’s the raison d’etre for the probiotic supplement industry for starters. The microbes that form it are all non-human, yet they control our digestion, send chemical signals to our brains, influence our mood, and play a key role in our immune system.

That these microbes affect human health has long been recognised, but it is only in the past 25 years that advances in genetic sequencing and computing allowed scientists to fully appreciate the microbiome’s wide-ranging importance.

Biomine launched its gut microbiome test to the public in July 2025. For a fee of about R5,000, those who are curious about what it is exactly that is living in their belly and further south send the company a small sample by courier, and about three weeks later they get the results.

These include a long list of microbes you have probably never heard of, and an assessment of the balance and diversity of your microbiome. As with society in general, the more diversity the better.

We really only understand the tip of the iceberg when it comes to the human microbiome

—  Dr Leah Murray

If a client gives their consent, the makeup of their faeces is fed into Biomine’s database to fuel its R&D. “We have also collected our own samples, with the money we raised and with grants that we have been awarded, which allows us to go out and look for specific people who can give us gut microbiome tests,” Castillo says.

The venture capital to get Biomine off the ground was provided by OneBio Venture Studio, which specialises in funding biotech entrepreneurs. It has set up an NPO, OneBio Innovation Centre, to provide laboratory facilities in Cape Town for the companies it backs, such as Biomine.

“Another application for the platform is to predict whether immuno-oncology drugs can work for people suffering from cancer,” Castillo says.

“These immune therapies cost more than R1m a year, they’re super expensive. And when they work, they work really well. But they only work for 40% of the population. Because of the correlation between the gut microbiome and the immune system, we can use the microbiome to predict whether the immuno-therapy for cancer is going to work for you or not.”

Castillo says Biomine is still focused on R&D and launching products, but “there might be some M&A options in the future”, with companies in such sectors as diagnostics and pharmaceuticals. “We’re building towards that, for sure.”

Castillo has a PhD in genetics, but neither he nor Barendsen has medical qualifications, and he stresses he cannot offer clients medical advice along with their test results. The faeces test is “a tool that tells you what is in your microbiome, but it is not diagnostic”.

Leah Murray, a Cape Town doctor who focuses on digestive health, says she’s not convinced that microbiome tests are “useful enough to spend the few thousand rand”.

“They’re definitely not my first port of call,” Murray, who describes what she does as “integrative and functional medicine”, tells the FM. “Most of the time, with the symptoms you can elicit what is likely going on with the gut … But if we get stuck, then it’s useful to check if you’ve got your keystone bacteria.”

These are “the main, very important good guys in the gut”. “We really only understand the tip of the iceberg when it comes to the human microbiome, but what we have found is that in healthy people there’s an abundance of keystone bacteria,” Murray says.

The South African Gastroenterology Society (SAGES) says: “Routine commercial gut microbiome testing is not supported for general clinical use outside research settings or specific specialist-directed indications at this stage.”

Citing an editorial in The Lancet, SAGES council member Dr Yonela Qubekile tells the FM: “The main concerns are that results can vary between companies, interpretation is not standardised, and many reports provide ‘dysbiosis scores’, dietary advice, probiotic recommendations, or supplement suggestions that are not yet strongly evidence-based.”