Spun out of the University of Chicago, the startup is built on research linking a healthy, butyrate-rich microbiome to food tolerance, and a dysbiotic, low-butyrate microbiome to food allergies. Further bioinformatic analysis of food-allergic versus non-allergic microbiomes identified that a single species, Anaerostipes caccae, was enriched in non-allergic individuals—and both produced butyrate and showed a strong positive association with intestinal barrier integrity and food tolerance.
Ahead of his Probiota Pioneers presentation at the upcoming Probiota Americas in Vancouver, Brett Newswanger, COO at ClostraBio, discusses how ClostraBio has advanced the delivery of butyrate to the lower gut to help restore normal barrier protective function.
NI: How did the ClostraBio team come together, and could you share a bit of the team’s and advisory board’s background?
BN: As a B2B-focused organization, we have a small team of dedicated entrepreneurs, scientists and product developers, and are excited to transform the gut health industry with our next-generation probiotic CLB101. Our executive leadership team, consisting of Ritu Shah, CEO, Brian Meehan, CSO, and myself bring over 60 years of combined experience in the pharmaceutical and biotechnology industries, where high integrity and a focus on science are paramount.
Our advisors Scott Ravech (former CEO of Deerland Probiotics & Enzymes, acquired by ADM) and David Keller (former VP Scientific Ops at Ganeden, acquired by Kerry) offer a wealth of industry knowledge and direct expertise in commercializing high quality dietary supplements.
Our scientific co-founder and advisor Jeffrey Hubbell (Professor at NYU School of Engineering and Grossman School of Medicine) is a pioneering bioengineer and serial entrepreneur with more than 400 published papers and 100 issued U.S. patents. We currently operate out of the biotech incubator Portal Innovations, with locations in both Chicago and Boston.
NI: What has gone into scaling the business to create real innovation?
BN: ClostraBio has always been a science-first organization with a focus on hypothesis-driven research. While mouse studies were important for testing initial hypotheses, our goal was to begin generating human data as soon as possible, to truly understand the impact of strains like CLB101 on human health and the gut microbiome. However, in order to begin clinical development, we needed to confirm safety (despite Anaerostipes caccae CLB101 being isolated from healthy humans) and scale-up manufacturing to establish GRAS status.
With regard to fermentation, it was important to ensure that we collaborated with one of the very few contract manufacturing partners who had experience with next-generation anaerobic strains. Strict anaerobes are notoriously difficult to manufacture and produce at the commercial scale while maintaining practical unit economics. As a strict anaerobe and a spore former, CLB101 is not easy to manufacture but has now demonstrated reproducibly high yields at the commercial scale. We are pleased with the great working relationship we share with our contract manufacturing partner.
With regard to GRAS affirmation, we wanted to go above and beyond what many supplement companies view as a paperwork exercise. As such, in addition to an extensive safety analysis of the CLB101 strain, we followed the advice of experts at GRASroots Consulting and spent significant time and resources conducting multiple in vivo toxicology studies. Once these numerous animal studies were successfully completed, we felt completely satisfied confirming the safety of our specific Anaerostipes caccae CLB101 strain.
When considering commercialization, we knew education would be the most important barrier in moving CLB101 forward, so it made sense to initially focus on the healthcare practitioner channel. Given the novelty of CLB101 we had interest from multiple parties but ultimately partnered with Designs for Health to launch Anaerostipes Probiotic in the practitioner channel given their integrity, experience and leadership in bringing science-backed products to market. To address the other channels to market, it was important to take a step back and acknowledge our organizational capabilities. In doing this, we quickly recognized that as a company, our strength is in product development, and we had limited bandwidth in building a full commercial team. As such we realized that partnering with an ingredient distributor would create an extension of our sales and marketing team to sell CLB101 to the consumer-focused supplement brands.
NI: How was CLB101 isolated, how does it work and what makes it next-gen?
BN: CLB101 is a strict obligate anaerobe isolated from healthy humans and shown to be in low abundance in children with food allergies. CLB101 resides in the lower gut where it provides a natural and continuous source of butyrate. As the primary energy source for colonocytes (cells that line the intestinal wall), it is well documented in literature that butyrate supports gut barrier integrity, provides immune support and balances the microbiome. These mechanisms tie into potential support for a condition often described as “leaky gut”. With depleted butyrate levels, individuals with food allergies can be described as having a leaky gut, as could individuals with food intolerances, IBS, or a host of related conditions. While food allergies affect about 30 million Americans and require a complex regulatory product development pathway, a far larger population of at least 100 million Americans suffer from food intolerances and other leaky-gut related conditions.
Compared to traditional probiotic bacteria which simply do not have the genetic capacity to make butyrate, the CLB101 strain is differentiated in that it is a direct butyrate producer. And CLB101 is unique among butyrate-producing strains in that it can produce butyrate in two ways: 1) by metabolizing prebiotic fiber and 2) through conversion of the bacterial byproducts acetate and lactate that are produced by most lactic-acid bacteria (LABs). This means formulating with CLB101 enables both prebiotic-probiotic (synbiotic) and probiotic-probiotic cross-feeding product opportunities with LABs.
NI: What science backs the strain? New studies underway?
BN: Preclinical efficacy data with CLB101 in mouse models of food allergy has been published in high-impact, peer-reviewed journals: Nature Medicine (Feehley, et. al 2019) and Cell Host & Microbe (Hesser et al, 2024).
CLB101 achieved GRAS self-affirmation in June 2025 following a comprehensive review of safety parameters and a series of in vivo toxicology studies demonstrating the strain was safe at very high doses when given to animals. This resulting data was published in the International Journal of Toxicology (Modica, et. al, 2025).
A clinical case study was published by Designs for Health, indicating CLB101 provided significant clinical benefit and modulated the microbiome of an individual patient with dairy sensitivities.
ClostraBio recently completed the first randomized, double-blind, placebo controlled clinical study with CLB101 demonstrating safety and tolerability in humans. Full clinical results, including efficacy data, will be published in the near future.
NI: Returning to commercialization strategy, how have ClostraBio’s partnerships with Designs for Health and Maypro contribute to the early success of CLB101? And what is next for ClostraBio?
BN: Designs for Health is widely recognized as one of the most innovative and science-forward brands within the HCP-focused channel. True to their reputation, they quickly recognized the novelty and high clinical potential of a direct butyrate-producer. Once it became apparent that DFH was also willing to invest in both educational and marketing efforts to support the launch of Anaerostipes Probiotic (the first product containing CLB101), our partnership fell into place rather quickly, well in advance of the commercial launch. This additional time for launch strategy planning led to quick uptake by HCPs and early commercial success with Anaerostipes Probiotic. But more important are the testimonials and case studies we received from individuals who have used CLB101 and are feeling better, in some cases after decades of dealing with food intolerances.
Our consumer-brand focused ingredient distribution partnership with Maypro fell into place soon after DFH’s launch in the HCP channel. With clinical data now in hand, our near-term focus is working with Maypro to communicate the clear mechanism-of-action, clinical benefits and advanced formulation opportunities available for brand partners who are interested in being first-movers with regards to next-generation strains like CLB101. Similar to many bacteria that consume prebiotics/fiber to produce various beneficial short-chain fatty acids, CLB101 utilizes specific fibers to generate butyrate - thus ClostraBio is interested in creating new synbiotic formulations with other ingredient partners. Further, CLB101 is differentiated in that it also converts lactate and acetate produced by traditional LABs into butyrate. This offers many opportunities for cross-feeding and creating probiotic-probiotic formulations. ClostraBio and Maypro are currently focused on partnering with consumer brands to launch CLB101-containing formulations to support consumers with gut health challenges.
NI: What are some of the greatest challenges and successes that you have encountered in the first years of the business?
BN: Greatest challenges: educating the marketplace on the differences between traditional LABs and next-generation, commensal strains like CLB101. For example, taxonomically speaking, CLB101 is as related to traditional LABs as a human is to a jellyfish. With very different strains, the focus should no longer be on comparing the number of CFUs and the price—however this is something that will need to be fully communicated to all audiences. Further, while some HCPs, consumers and brands may be familiar with butyrate, it is important to understand that butyrate is only effective if it truly reaches the lower gut in a sufficient, continuous dose, to mimic the natural butyrate production observed in a healthy microbiome.
Greatest successes: first – seeing the positive impact CLB101 has had on individuals who are taking the product consistently, especially those who have had a long history of gut health issues or food sensitivities. People are finally feeling better, and we are proud that CLB101 could help. Second – partnerships. As a small company, we need partners to help build awareness and education around CLB101 and butyrate. We are fortunate to have built relationships with Designs for Health and Maypro and look forward to continued success.
NI: As one of our pioneers, could you outline your approach or ethos in treading a path or direction that no other firm has gone before? How do you weigh up the risks and benefits here?
BN: What ClostraBio is doing is difficult. Strains like CLB101 are only found in the strictly anaerobic confines of the lower intestine, so when we started, we had no idea if the strain could be fermented at the commercial scale in an economically feasible manner.
We recognize the importance of acting with urgency to positively impact human health, but we strongly believe that we must balance this with a thoughtful, careful and methodical scientific approach. We believe that our success can help fuel the success of others in this space and that together we can ultimately help unlock the true potential of our gut microbiomes.
Our ethos also includes ensuring the highest quality of product and making substantiated claims. We are not looking for shortcuts. We want to be known as an R&D powerhouse and a scientific engine of the industry. We have developed a novel, science-backed strain after years of research, but there have been many risks associated with our approach. Next-gen strains are more expensive to manufacture and thus require premium pricing. But the benefits of our approach outweigh risks. We have something that is helping to solve a real unmet need in the marketplace, and consumers want and deserve new solutions.
NI: In the probiotic, prebiotic and microbiome space, what would you say is the next research area that the industry needs to keep its eye on?
BN: What people put into their bodies on a regular basis is rapidly changing, and that can have profound implications for the gut microbiome (prescription opioid use is down, alcohol consumption is down in younger generations, but usage of GLP-1s and anti-depressants are up)—can pro/prebiotics support healthy change?
Advances in AI in areas like mass spectrometry will open the door to identifying and characterizing a multitude of microbiome-associated molecules that will enable our industry to focus on molecules other than SCFA.
With the launch of CLB101 we have just scratched the surface in commercializing one of the many next-generation commensal strains that are sure to provide numerous benefits to human health. As researchers continue to uncover the many intricacies of the human microbiome, they will no doubt create more product opportunities for the biotics industry. We all need to pay attention, and the industry will need to continue working hard and investing in technology to manufacture these sensitive strains.
We also believe brands and ingredient suppliers will become more interested in the subset of butyrate-producing strains, to fill the immense gap in their product portfolios. Butyrate is the primary energy source for colonocytes, the cells that line the intestinal wall. When butyrate is in low abundance, intestinal barrier integrity issues abound, leading to many adverse health conditions. We as an industry have to invest in more research around all aspects of gut health that tie to butyrate (or lack thereof) and focus more on conditions related to women’s health and the gut-brain axis.
NI: Finally, what is the significance for ClostraBio of being named one of our 2026 Probiota Pioneers, and how do you think it helps your profile in such an innovative, ever-changing industry?
BN: The industry has been talking about next-generation probiotics for years, but to date there has been little progress in commercializing strictly-anaerobic human commensals due to understandable technical and scientific challenges. We are delighted to be recognized by NutraIngredients for our commitment to science and human health, and all the hard work that was required to commercialize CLB101. We hope this shows the biotics industry that following hypothesis-driven research can drive true innovation and help move the needle in our collective understanding of the complexities of the human microbiome. But perhaps more importantly, at ClostraBio, we hope that being named a 2026 Probiota Pioneer helps demonstrate our commitment to providing new tools for the many affected people to manage their gut health issues.
