The ocean has spent hundreds of millions of years perfecting the chemistry of tearing chitin apart, and scientists in India have now borrowed that machinery to attack one of medicine’s most troubling fungi. In a study published on 27 August 2026 in the open-access journal Applied Microbiology and Biotechnology, a team spanning the Manipal Institute of Technology, the National Institute of Technology Karnataka, the Jawaharlal Nehru Centre for Advanced Scientific Research and the Post Graduate Institute of Medical Education and Research reports that a marine bacterial chitinase, named BtChi, strips away a critical structural polymer from the cell walls of Candida fungi. The purified enzyme, a 71-kilodalton protein with a measured total activity of 438.6 units, inhibited growth across a panel of Candida species at concentrations ranging from 7.8 to 250 micrograms per milliliter. Most strikingly, Candida auris — the multidrug-resistant yeast that has alarmed hospital epidemiologists worldwide — proved among the most susceptible organisms tested, with the concentration required to inhibit half of the strains measured at just 3.9 micrograms per milliliter.
The finding arrives at a moment when the antifungal armamentarium is thinning dangerously. Unlike the dozens of antibiotic classes available against bacteria, antifungal drugs come from only a handful of structural families: the polyenes, which bind ergosterol and punch holes in fungal membranes; the azoles, which block ergosterol biosynthesis; the echinocandins, which inhibit the synthesis of β-glucan, the wall’s main load-bearing polysaccharide; and the older nucleoside analogue flucytosine. Each carries liabilities. Amphotericin B, the workhorse polyene, is notoriously nephrotoxic; azole resistance is now entrenched in clinical populations; and echinocandin resistance is climbing in both Candida auris and Candida glabrata through mutations in the drug’s target enzyme. The deeper problem is evolutionary. Fungi are eukaryotes, our distant cousins on the tree of life, and many of their core cellular processes — from DNA replication to protein synthesis — resemble our own so closely that they make poor drug targets. That bottleneck has pushed researchers toward the one structure human cells conspicuously lack: the fungal cell wall, a rigid exoskeleton of cross-linked polysaccharides and glycoproteins that the cell must continuously remodel in order to grow, divide and withstand osmotic pressure.
Within that wall, chitin occupies a special position. Chemically, it is a linear polymer of N-acetylglucosamine units joined by β-1,4 glycosidic bonds — the same linkage architecture that stitches cellulose together in plants — and it forms a tough inner scaffold beneath the outer layers of β-glucan and mannoproteins. Although chitin accounts for only a small fraction of the wall’s dry mass in Candida, its structural role is outsized: it concentrates at the bud necks where daughter cells emerge and at the septa that divide one cell from another, acting as a load-bearing ring during the most mechanically stressful moments of the yeast life cycle. Crucially for medicine, fungi treat chitin as a rescue material. When echinocandin drugs suppress β-glucan synthesis, Candida cells often respond by thickening their chitin layer, and elevated chitin content has been linked to echinocandin treatment failure. An agent that attacks chitin directly would therefore strike not only a wall component in its own right, but also the very contingency plan that fungi deploy when other drugs arrive — and because humans neither synthesize chitin nor build any structural tissue from it, the polymer offers a selectivity gradient that conventional metabolic targets rarely achieve.
Chitinases — the glycoside hydrolase enzymes that cleave those β-1,4 bonds — are everywhere in nature, and the ocean is their great engine room. Marine ecosystems recycle enormous quantities of chitin every year from crustacean molts, krill, plankton and other arthropod debris, and marine bacteria have evolved elaborate chitinolytic systems to exploit this bonanza as their primary carbon and nitrogen source. Enzymes forged in seawater often carry useful biochemical gifts: tolerance to salt, robustness across pH ranges and a stability profile that terrestrial counterparts do not always match. The Indian team tapped this reservoir, expressing the BtChi enzyme in the laboratory and purifying it as a 71-kilodalton protein with a total activity of 438.6 units. When the purified preparation was titrated against a panel of Candida species, minimum inhibitory concentrations ranged from 7.8 to 250 micrograms per milliliter depending on the species — a spectrum the authors characterize as broad yet species-specific, consistent with the idea that different Candida species expose or shield their wall chitin to different degrees.
The standout result concerned Candida auris. Across the tested isolates, the enzyme delivered an MIC50 of 3.9 micrograms per milliliter and an MIC90 of 7.8 micrograms per milliliter, meaning that half of the strains were inhibited at the lower concentration and ninety percent at the higher one. Those numbers matter because of what C. auris represents. Since its simultaneous global emergence on three continents in the mid-2010s, the yeast has caused outbreaks in intensive care units across dozens of countries, persists on hospital surfaces and human skin for weeks, shrugs off many common disinfectants, and routinely defies fluconazole while amphotericin B and echinocandin failures accumulate. Many clinical isolates qualify as multidrug-resistant, and a worrying minority have proven pan-resistant, leaving clinicians with almost no options. Against this backdrop, any molecule that inhibits the organism at single-digit microgram concentrations commands attention — and one that does so by physically digesting a structural polymer, rather than poisoning a metabolic enzyme, may be harder for the fungus to circumvent through the familiar route of target-site mutation.
Inhibiting growth is one thing; killing cells outright is another. The researchers therefore ran time-kill assays, tracking viable colony-forming units over hours of enzyme exposure. For most of the Candida species tested, BtChi achieved reductions of at least 3 log10 CFU per milliliter — a thousand-fold drop, the conventional benchmark for fungicidal activity — within a window of 12 to 20 hours. Two species broke the pattern: Candida parapsilosis, with a maximum reduction of 1.67 log10 CFU per milliliter, and C. auris, with 0.4 log10. The authors describe the enzyme’s profile as fungicidal-like and species-dependent, and the heterogeneity is informative rather than merely disappointing. Cell wall architecture varies substantially across the Candida genus: the ratio of β-glucan to chitin, the density of the outer mannoprotein coat, and the efficiency of wall-repair and stress-response pathways all differ from species to species, and any of these factors could modulate how readily a 71-kilodalton protein reaches and dismantles the chitin layer beneath. For C. auris, the potent inhibition reflected in its low MIC values suggests that the enzyme suppresses the fungus effectively even where outright killing lags behind.
Two independent lines of evidence then tied the antifungal effect to chitin digestion. Microscopic analysis — carried out using confocal imaging facilities at the Manipal School of Life Sciences and scanning electron microscopy at the Central Research Facility of NITK Surathkal — revealed clear cell wall damage in enzyme-treated cells, structural disruption of precisely the layer the enzyme is built to attack. Complementing the imaging, high-performance liquid chromatography performed at the School of Civil and Chemical Engineering detected the release of monomeric, dimeric and trimeric chitooligosaccharides from the treated cultures. Those small soluble sugars are the expected products of chitinase action: the enzyme processively hydrolyzes the β-1,4 backbone of chitin, clipping the insoluble polymer into short oligosaccharides and, ultimately, N-acetylglucosamine monomers. Observing the wall physically compromised while its digestion products accumulate in solution gives the mechanistic argument a satisfying closed loop. The enzyme binds its substrate within the wall, cuts, and the wall’s integrity fails, leaving the cell to buckle under its own internal turgor pressure — a mode of death that looks less like metabolic poisoning and more like structural demolition.
The therapeutic logic extends beyond monotherapy. Because echinocandin stress drives fungi to reinforce their walls with extra chitin, a chitinase could in principle subvert that rescue response, sensitizing cells to existing drugs or dismantling the very mechanism behind echinocandin failure. The chitooligosaccharides that BtChi releases are not inert debris, either: short chitin oligomers are recognized by innate immune systems and act as biological signals in contexts ranging from plant defense priming to mammalian immunology, adding a possible second layer of activity. Enzyme-based antimicrobials also carry an appealing property at a time when resistance dominates the headlines — resistance through target mutation is difficult to evolve against a physical polymer that the cell cannot simply redesign without paying a steep fitness cost. The caveats, however, are real. Delivering a 71-kilodalton protein systemically poses challenges of proteolytic degradation, immunogenicity, manufacturing cost and tissue penetration, and no enzyme antifungal has yet navigated the full path of clinical development. Nearer-term applications may therefore lie in topical formulations, catheter-lock solutions, wound dressings or agricultural protection, where protein drugs face fewer delivery barriers and where biofilms of Candida on medical devices remain a persistent problem.
For now, the study stands as a proof of concept that a single marine enzyme can, on its own, cripple the walls of some of the most clinically feared Candida species. The authors, whose team included co-first authors Rachana Arvind and Smruti Bhat, frame the work around three key points: BtChi exhibits species-specific antifungal activity; it produces species-dependent fungicidal effects in killing kinetics against C. albicans and non-albicans species; and it targets chitin in the Candida cell wall while releasing chitooligosaccharides. Translating that chemistry into medicine will require stability engineering, delivery vehicles and rigorous safety profiling, steps that typically span years and substantial investment. But the direction of travel is unmistakable. The World Health Organization’s first fungal priority pathogens list placed C. auris in its critical group, and the pipeline of genuinely new antifungal classes remains conspicuously thin even as invasive fungal infections claim well over a million lives each year. An enzyme that ocean bacteria use to recycle crab shells and krill may not reach the pharmacy soon, yet it demonstrates something the field badly needs: that the fungal wall’s most stubborn material can be made to fail, and that the next generation of antifungals may be built not to poison cells but to take them apart.
Subject of Research: Antifungal activity of the marine bacterial chitinase BtChi against Candida species, mediated by targeting cell wall chitin and releasing chitooligosaccharides
Subject of Research: Biology
Article Title: Marine chitinase BtChi disrupts cell wall integrity in Candida albicans and non-albicans species by chitin targeting and release of chitooligosaccharides
Article References: Arvind, R., Bhat, S., Pai, V. N., P., A. S., V., A. P., Narayanan, A., Sanyal, K., Rudramurthy, S., Raval, K., & Raval, R. (2026). Marine chitinase BtChi disrupts cell wall integrity in Candida albicans and non-albicans species by chitin targeting and release of chitooligosaccharides. Applied Microbiology and Biotechnology. https://doi.org/10.1007/s00253-026-14012-8
Image Credits: AI Generated
DOI: 10.1007/s00253-026-14012-8
Keywords: Chitin, Chitinase, Candida species, Candida auris, Antifungal, Drug resistance, Cell wall integrity, Chitooligosaccharides, Marine bacteria, Enzyme antimicrobial
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Drew Townsend. (August 30, 2026). Marine chitinase BtChi attacks Candida cell walls, releasing antifungal chitooligosaccharides. Scienmag. https://scienmag.com/marine-chitinase-btchi-attacks-candida-cell-walls-releasing-antifungal-chitooligosaccharides/
Drew Townsend. “Marine chitinase BtChi attacks Candida cell walls, releasing antifungal chitooligosaccharides.” Scienmag, 30 August 2026, https://scienmag.com/marine-chitinase-btchi-attacks-candida-cell-walls-releasing-antifungal-chitooligosaccharides/. Accessed 30 August 2026.
Drew Townsend. “Marine chitinase BtChi attacks Candida cell walls, releasing antifungal chitooligosaccharides.” Scienmag. August 30, 2026. https://scienmag.com/marine-chitinase-btchi-attacks-candida-cell-walls-releasing-antifungal-chitooligosaccharides/
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Tags: antifungal chitooligosaccharidesantifungal drug developmentantimicrobial potential of marine enzymesbiomedical applications of marine enzymesBtChi enzymeCandida auris drug resistanceCandida cell wall degradationchitinase enzyme activitychitinase inhibition of fungifungal cell wall targetingmarine bacteria antifungal enzymesmarine biochemistry for medicinemarine chitinasemicrobial enzymes in medicinenatural antifungal agentsnovel antifungal agents
