Between 2023 and 2024, researchers collected dead and decaying twigs bearing fungal fruiting bodies from macadamia plantations in Yunnan Province in southwestern China and Chiang Mai Province in northern Thailand. These two regions are significant for different reasons. China first introduced macadamia in the 1970s and now accounts for more than 60 percent of the world’s cultivated macadamia area, with Yunnan alone representing 88 percent of that national footprint, making it the largest macadamia-growing region on Earth. Thailand, where the crop was trialed experimentally as early as 1953, has seen rapid expansion of plantations in the north, particularly around Chiang Mai, as domestic consumption and export potential have grown.

Back in the laboratory, the team combined classical morphological examination with modern molecular systematics to work out exactly what they had collected. Under compound and stereomicroscopes they documented the fine details of fungal anatomy: the size and shape of the flask-like fruiting bodies known as ascomata, the layered structure of their walls, the form of spore-producing sacs called asci, and the dimensions, septation, and surface texture of the ascospores themselves. For the molecular work, DNA was extracted from pure cultures, and six genetic loci were amplified and sequenced, including the internal transcribed spacer region (ITS), the nuclear large and small ribosomal subunits (nrLSU and nrSSU), and the protein-coding genes tef1-α, tub2, and rpb2. These sequences were aligned, combined, and analyzed using maximum likelihood and Bayesian inference methods, generating phylogenetic trees for each fungal genus with strong statistical support at the critical nodes.

The results were striking. Eighteen fungal taxa were identified across ten genera and seven families, all within the phylum Ascomycota. Five of these proved to be new to science: Dothiorella lignicola, Lasiodiplodia macadamiae, Palmiascoma macadamiae, Xylochrysis macadamiae, and Xylochrysis yunnanensis. Each was formally described and named according to the International Code of Nomenclature for algae, fungi, and plants, with type specimens deposited in herbaria in China and Thailand and living cultures preserved in culture collections. In several cases, the new species were separated from their closest relatives by a combination of subtle morphological differences and substantial genetic distances. Xylochrysis macadamiae, for example, differs from its nearest known relatives in having larger, semi-immersed fruiting bodies and rough-walled ascospores, along with nucleotide differences of around 7 to 12 percent in key gene regions.

Thirteen previously described species were also recorded from macadamia for the first time, spanning genera such as Sporidesmium, Crassiparies, Chromolaenicola, Montagnula, Pseudochaetosphaeronema, and Helminthosporium. Several of these records were also new geographic findings, extending known distributions across national borders. Perhaps most intriguingly, the sexual reproductive structures of three species, Chromolaenicola ananasi, Pseudochaetosphaeronema siamense, and Helminthosporium nanjingense, had never been observed before; this study documented them for the first time, filling significant gaps in mycological knowledge. Eight of the ten genera encountered had never previously been reported from macadamia anywhere in the world.

One species had a tangled taxonomic backstory. Dothiorella lignicola had been described earlier under a different name, but that earlier name was formally rejected because its original description was based on an incorrect host, species name, etymology, and DNA sequences, a violation of Article 52.1 of the nomenclatural code. The replacement name D. lignicola, referring to the fungus’s wood-dwelling habit, now stands, anchored by a Thai collection whose tef1-α gene sequences differ from its closest relatives by more than 20 base pairs, alongside consistent morphological distinctions such as larger, ovoid conidia.

Identifying the fungi was only half of the study. Because saprobic fungi survive by secreting enzymes that dismantle tough plant polymers, the researchers wanted to know what these macadamia colonizers could actually digest. Twenty pure cultures representing the 18 species were screened on agar plates for four lignocellulolytic enzymes: cellulase, xylanase, mannanase, and laccase. For the first three enzymes, plates containing carboxymethyl cellulose, xylan, or locust bean gum were flooded with Congo red after incubation; where enzymes had broken down the substrate, a clear halo appeared around the fungal colony. Laccase activity was detected instead on guaiacol agar, where the enzyme oxidizes the compound to produce a brownish-red color change. Enzyme output was quantified with an enzyme potency index, calculated from the difference between the halo diameter and the colony diameter, and all experiments were run in triplicate with statistical analysis by one-way ANOVA and Duncan’s multiple range test.

The enzyme screening revealed a community of capable biomass degraders, but with clear patterns of specialization. Xylanase was the most frequently detected activity, produced by 17 isolates representing 15 species, followed by cellulase, found in 14 isolates from 12 species, and mannanase, found in 10 isolates from nine species. Laccase, the oxidative enzyme needed to attack the chemically stubborn lignin fraction of plant cell walls, appeared in only five isolates. The single strongest xylanase producer was the newly described Xylochrysis macadamiae, with an enzyme potency index of 3.50, followed by Sporidesmium tropicale at 3.10. In the cellulase category, two Helminthosporium species dominated, with H. puerense reaching an index of 2.25. Mannanase activity peaked in Pseudochaetosphaeronema puerense at 1.98, while Sporidesmium tropicale led laccase production at 2.20. Only three isolates, Dothiorella lignicola and two Lasiodiplodia species, showed no detectable activity for any enzyme, possibly because their enzyme production fell below the assay’s detection limit or because they preferentially consumed simple sugars available in the medium.

The predominance of xylanase makes ecological sense. Hemicellulose, the xylan-rich matrix that surrounds cellulose fibers in plant cell walls, is less crystalline and more chemically accessible than cellulose itself, so decomposer fungi typically attack it first, gaining access to the more recalcitrant components afterward. Lignin, encrusted around the cellulose in hardwood twigs, requires specialized oxidative enzymes such as laccases and peroxidases, which relatively few ascomycetes produce in quantity. The observed enzyme profile of the macadamia community mirrors this well-known decomposition sequence, and the four isolates that produced all four enzymes tested, including Crassiparies quadrisporus, Pseudochaetosphaeronema chiangraiense, and Sporidesmium tropicale, stand out as particularly versatile degraders.

Beyond their ecological role in recycling carbon, nitrogen, and phosphorus through decaying orchard wood, these fungi have potential commercial value. Lignocellulolytic enzymes are workhorses of industrial biotechnology, used in converting plant biomass to biofuels, in food and feed processing, in pulp and paper manufacture, in textile production, and in environmental bioremediation. The authors suggest that the next steps should include quantitative enzyme assays, optimization of culture conditions, and purification and biochemical characterization of the most promising enzymes. For now, the study’s core message is clear: even beneath one of the world’s most intensively studied nut crops, entire communities of fungi, including species unknown to science, have been quietly waiting on dead twigs, and some of them carry enzymatic toolkits worth far more than their weight in nuts.

Subject of Research: Diversity, taxonomy, and lignocellulolytic enzyme production of saprobic microfungi associated with macadamia in China and Thailand

Article Title: New species and additional records of saprobic microfungi associated with Macadamia in China and Thailand and their lignocellulitic enzyme production

Article References: Zhang, X., Karunarathna, S. C., Tibpromma, S., Senwanna, C., Kumla, J., Du, T.-Y., Elgorban, A. M., Alfagham, A. T., Filimban, F. Z., Dai, D.-Q., & Suwannarach, N. (2026). New species and additional records of saprobic microfungi associated with Macadamia in China and Thailand and their lignocellulitic enzyme production. MycoKeys, 141, 217-281. https://doi.org/10.3897/mycokeys.141.209886

Image Credits: AI Generated

DOI: 10.3897/mycokeys.141.209886

Keywords: macadamia, saprobic fungi, new species, taxonomy, phylogenetics, lignocellulolytic enzymes, xylanase, cellulase, laccase, biotechnology, China, Thailand

Xylanase itself is a fascinating target. The enzyme, classified as endo-1,4-beta-xylanase (EC 3.2.1.8), specifically attacks xylan, the complex polysaccharide that ranks as the second most abundant polymer in nature after cellulose and forms a major structural component of plant cell walls. By cutting the beta-1,4-glycosidic bonds threaded through xylan chains, the enzyme releases xylose and xylooligosaccharides, sugars with enormous commercial value. Xylanases are sorted by the carbohydrate-active enzymes database into glycoside hydrolase families, with GH10 and GH11 by far the best characterized; their members differ subtly in substrate specificity, catalytic mechanism, and optimal operating conditions, which in turn shapes their industrial niches. In food processing, xylanases modify the water-binding behavior of bread dough, increasing loaf volume and improving crumb structure, while in animal feed they reduce the viscosity of non-starch polysaccharides to boost nutrient absorption. Beyond food, the same enzyme pre-bleaches kraft pulp in the paper industry and helps open up lignocellulosic biomass for bioethanol production.

The enzyme is sourced from an impressively diverse biological roster. Bacterial genera such as Bacillus, Streptomyces, and Clostridium produce xylanases prized for their thermal and pH robustness — Bacillus species in particular yield thermostable variants suited to high-temperature processing. Fungal producers, including Aspergillus, Trichoderma, and Penicillium, dominate food and feed applications thanks to their efficiency at degrading complex xylans. Plants make xylanases during germination and fruit ripening, and certain herbivorous insects and termites harbor gut microbes that degrade plant cell walls with the enzyme’s help, though plant and animal sources remain marginal industrially. Recombinant DNA technology now allows xylanase genes to be cloned and expressed in hosts such as Escherichia coli and Pichia pastoris, multiplying yields far beyond what natural fermentation achieves. Even so, free enzymes remain fragile in industrial reactors, which is precisely where immobilization — attaching the enzyme to a solid support — enters the picture, a concept dating back to 1916 when charcoal-embedded invertase was first shown to hydrolyze sucrose.

Metal-organic frameworks emerged in the late 1990s as a new class of crystalline solids built from metal ions or clusters coordinated to organic linkers into extended, lattice-like networks. Their defining feature is porosity taken to an extreme: some MOFs boast surface areas exceeding 7000 square meters per gram, among the highest of any known material, offering a vast internal landscape for hosting guest molecules. Just as importantly, MOFs are programmable. By swapping metal nodes and organic struts, chemists can tune pore size, pore shape, and surface functionality with a precision unavailable to conventional carriers such as chitosan beads, alginate gels, or polyaniline films. Synthesis routes are equally varied, ranging from conventional hydrothermal heating under pressure to solvent-free mechanochemical grinding, electrochemical deposition on electrodes, and rapid microwave-assisted growth that produces highly crystalline particles in a fraction of the usual time.

For xylanase, the review highlights several standout MOF platforms. Manganese-doped ZIF-67, a zeolitic imidazolate framework, was used in a comparative study to immobilize xylanase via an in-situ method, with striking results. Encapsulated xylanase retained 85.7 percent of its activity after two hours at 70 degrees Celsius, while the free enzyme plummeted to 28.7 percent. Both the standard and manganese-doped versions kept more than 70 percent of their initial activity through eight consecutive reaction cycles, and the doped variant showed the highest substrate affinity. Functionalized UiO-66-NH2, a zirconium-based framework, served as the scaffold for co-immobilizing beta-xylosidase and endoxylanase, a pairing that maintained over 95 percent relative activity at 95 degrees Celsius in a 50 percent acetone solution and halved the enzyme’s Km value, indicating markedly improved substrate binding. A magnetic Fe3O4@polydopamine@MOF composite achieved protein loading of 80.67 milligrams per gram through multipoint interactions while tolerating both acidic and alkaline conditions.

The immobilization chemistry itself spans a spectrum of strategies, each with distinct trade-offs. Physical adsorption, the simplest approach, relies on weak van der Waals forces, hydrogen bonds, and electrostatic attraction to tether the enzyme to the MOF surface, preserving the protein’s native structure but risking gradual leaching into the product. Covalent bonding forms durable chemical links between amine, carboxyl, or thiol groups on the enzyme and complementary groups on the framework, essentially eliminating leaching at the cost of more elaborate preparation and occasional active-site interference. In-situ encapsulation is arguably the most elegant: enzyme molecules are trapped inside the growing MOF crystal as it assembles around them, creating a protective environment from which escape is nearly impossible. Covalent cross-linking with bifunctional reagents builds a stable enzyme network throughout the pores and across the surface, boosting resistance to harsh conditions. In one demonstration, beta-xylosidase cross-linked onto FeSO4-chitosan-encapsulated MOF microparticles retained 40 percent activity after ten reuse cycles and functioned at temperatures five degrees higher than the free protein, with double the activity at 70 degrees.

Real-world food applications are already validating the concept. A xylanase from a novel Bacillus pumilus strain, immobilized on the copper-based framework Cu-BTC, clarified pineapple and pomegranate juices with enhanced catalytic efficiency and remarkable durability, retaining 61 percent of its activity after 21 cycles. In apple juice trials, Xyl@ZIF-67 raised juice transmittance from 65.61 to 94.73 percent within an hour of treatment, while the manganese-doped version lifted it from 77.80 to 84.13 percent, simultaneously increasing reducing sugar content. Xylooligosaccharide production — a booming market for prebiotic ingredients that selectively nourish beneficial Bifidobacteria and Lactobacilli in the human gut — has proven equally receptive. The magnetic Fe3O4@PDA@MOF-xylanase system converted corncob xylan into xylooligosaccharides at a 23 percent yield, outperforming the free enzyme by a factor of 1.15, while a green-synthesized Xy-Cu-BTC composite achieved an 87.4 percent conversion yield, boosting xylopentose output and suppressing unwanted xylose formation to just 0.88 percent of the product mix.

Challenges remain, and the review does not gloss over them. Leaching persists whenever weak non-covalent interactions are disrupted by shifts in pH, ionic strength, or temperature. Mass-transfer limitations loom large because xylan is a bulky, high-molecular-weight polymer; if MOF pore apertures are too narrow, substrate chains simply cannot reach the immobilized active sites, dragging down reaction rates compared with free enzyme. Aqueous stability is a further concern, as water molecules can competitively displace organic linkers from metal centers, collapsing some frameworks — a problem researchers counter by turning to chemically robust series such as ZIF and MIL frameworks, which simultaneously act as a molecular corset restricting protein unfolding. Food safety adds a final layer of scrutiny: frameworks built from toxic metals such as chromium or cobalt risk contaminating food matrices, so current research favors biocompatible MOFs assembled from iron, zinc, or calcium nodes with Generally Recognized as Safe ligands such as amino acids or citric acid, validated by rigorous leaching assays in food-simulating solvents.

The path forward, the review concludes, lies in hierarchical pore engineering that integrates mesopores large enough for xylan polymers, a transition to aqueous green synthesis routes, and continuous-flow biocatalysis in packed-bed reactors for pulp, bioethanol, and food production. The economics, too, must balance out: MOF supports cost more upfront than silica or chitosan, a premium justified only if exceptional reusability and extended enzyme half-life reduce replacement frequency and simplify downstream recovery. With the immobilized enzyme market projected to reach USD 27.29 billion by 2031 at a compound annual growth rate of 9.45 percent, the commercial incentive to solve these problems is unmistakable. If MOF-encapsulated xylanase delivers on its laboratory promise at industrial scale, the crystal cages now being grown around this humble enzyme could quietly reshape how the world’s food — from breakfast juice to prebiotic supplements — is made.

Subject of Research: Metal-organic framework composites for xylanase enzyme immobilization and their applications in the food industry

Article Title: Metal organic framework composites for xylanase immobilization and their applications in food industry

Article References: Jana, U. K. (2026). Metal organic framework composites for xylanase immobilization and their applications in food industry. Discover Industrial Chemistry and Materials, 1(1), Article 9. https://doi.org/10.1007/s44508-026-00011-0

Image Credits: AI Generated

DOI: 10.1007/s44508-026-00011-0

Keywords: metal-organic frameworks, xylanase, enzyme immobilization, biocatalysis, xylooligosaccharides, fruit juice clarification, ZIF-67, UiO-66-NH2, food safety, prebiotics, nanobiotechnology, food industry