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Cello-oligosaccharides (COS) become a new type of functional oligosaccharides. COS transglycosylation reactions were studied to enhance COS yield production. Seeking the ability of the free form of Fusarium solani ß-glucosidase (FBgl1) to synthesize COS under low substrate concentrations, we found out that this biocatalyst initiates this reaction with only 1 g/L of cellobiose, giving rise to the formation of cellotriose. Cellotriose and cellopentaose were detected in biphasic conditions with an immobilized FBgl1 and when increased to 50 g/L of cellobiose as a starter concentration. After the biocatalyst recycling process, the trans-glycosylation yield of COS was maintained after 5 cycles, and the COS concentration was 6.70 ± 0.35 g/L. The crude COS contained 20.15 ± 0.25 g/L glucose, 23.15 ± 0.22 g/L non-reacting substrate cellobiose, 5.25 ± 0.53 g/L, cellotriose and 1.49 ± 0.32 g/L cellopentaose. A bioprocess was developed for cellotriose enrichment, using whole Bacillus velezensis cells as a microbial purification tool. This bacteria consumed glucose, unreacted cellobiose, and cellopentaose while preserving cellotriose in the fermented medium. This study provides an excellent enzyme candidate for industrial COS production and is also the first study on the single-step COS enrichment process.

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Background: Sequestering carbon dioxide (CO2) in agricultural soils promises climate change mitigation as well as sustainable ecosystem services. In order to stabilize crop residues as soil carbon (C), addition of mineral nutrients in excess to crop needs is suggested as an inevitable practice. However, the effect of two macronutrients i.e., nitrogen (N) & phosphorus (P), on C cycling has been found contradictory. Mineral N usually decreases whereas mineral P increases the soil organic C (SOC) mineralization and microbial biomass. How the addition of these macronutrients in inorganic form to an organic-matter poor soil affect C cycling remains to be investigated. Methods: To reconcile this contradiction, we tested the effect of mineral N (120 kg N ha-1) and/or P (60 kg N ha-1) in presence or absence of maize litter (1 g C kg-1 soil) on C cycling in an organic-matter poor soil (0.87% SOC) in a laboratory incubation. Soil respiration was measured periodically during the incubation whereas various soil variables were measured at the end of the incubation. Results: Contrary to literature, P addition stimulated soil C mineralization very briefly at start of incubation period and released similar total cumulative CO2-C as in control soil. We attributed this to low organic C content of the soil as P addition could desorb very low amounts of labile C for microbial use. Adding N with litter built up the largest microbial biomass (144% higher) without inducing any further increase in CO2-C release compared to litter only addition. However, adding P with litter did not induce any increase in microbial biomass. Co-application of inorganic N and P significantly increased C mineralization in presence (19% with respect to only litter amended) as well as absence (41% with respect to control soil) of litter. Overall, our study indicates that the combined application of inorganic N and P stabilizes added organic matter while depletes the already unamended soil.

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Functionalized mesoporous materials have become a promising carrier for enzyme immobilization. In this study, Santa Barbara Amorphous 15 (SBA-15) was modified by N-aminoethyl-γ-aminopropyl trimethoxy (R). R-SBA-15 was employed to purify and immobilize recombinant ß-glucosidase from Terrabacter ginsenosidimutans (BgpA) in one step for the first time. Optimum pH of the constructed R-SBA-15@BgpA were 7.0, and it has 20 â„ƒ higher optimal temperature than free enzyme. Relative activity of R-SBA-15@BgpA still retained > 70% at 42 â„ƒ after 8-h incubation. The investigation on organic reagent resistance revealed that the immobilized enzyme can maintain strong stability in 15% DMSO. In leaching test and evaluation of storage stability, only trace amount of protein was detected in buffer of the immobilized enzyme after storage at 4 â„ƒ for 33 days, and the immobilized BgpA still maintained > 50% relative activity. It also demonstrated good reusability, with 76.1% relative activity remaining after fourteen successive enzymatic hydrolyses of epimedin A to sagittatoside A. The newly proposed strategy is an effective approach for the purification and immobilization of BgpA concurrently. In addition, R-SBA-15@BgpA was demonstrated to have high efficiency and stability in this application, suggesting its great feasibility and potential to produce bioactive compounds such as secondary glycosides or aglycones from natural products.

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The formation and analysis of amyloid fibers by two ß-glucosidases, BglA and BglB, belonging to the GH1 enzyme family, are reported. Both proteins have the (ß/α)8 TIM-barrel fold, which is characteristic of this family and is also the most common protein structure. BglA is an octamer, whereas BglB is a monomer. Amyloid fibrillation using pH and temperature as perturbing agents was investigated using fluorescence spectroscopy as a preliminary approach and corroborated using wide-field optical microscopy, confocal microscopy, and field-emission scanning electron microscopy. These analyses showed that both enzymes fibrillate at a wide range of acidic and alkaline conditions and at several temperature conditions, particularly at acidic pH (3-4) and at temperatures between 45 and 65 °C. Circular dichroism spectroscopy corroborated the transition from an α-helix to a ß-sheet secondary structure of both proteins in conditions where fibrillation was observed. Overall, our results suggest that fibrillation is a rather common phenomenon caused by protein misfolding, driven by a transition from an α-helix to a ß-sheet secondary structure, that many proteins can undergo if subjected to conditions that disturb their native conformation.

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Family GH1 glycosyl hydrolases are ubiquitous in prokaryotes and eukaryotes and are utilized in numerous industrial applications, including bioconversion of lignocelluloses. In this study, hyperacidophilic archaeon Cuniculiplasma divulgatum (S5T=JCM 30642T) was explored as a source of novel carbohydrate-active enzymes. The genome of C. divulgatum encodes three GH1 enzyme candidates, from which CIB12 and CIB13 were heterologously expressed and characterized. Phylogenetic analysis of CIB12 and CIB13 clustered them with ß-glucosidases from genuinely thermophilic archaea including Thermoplasma acidophilum, Picrophilus torridus, Sulfolobus solfataricus, Pyrococcus furiosus, and Thermococcus kodakarensis. Purified enzymes showed maximal activities at pH 4.5-6.0 (CIB12) and 4.5-5.5 (CIB13) with optimal temperatures at 50°C, suggesting a high-temperature origin of Cuniculiplasma spp. ancestors. Crystal structures of both enzymes revealed a classical (α/ß)8 TIM-barrel fold with the active site located inside the barrel close to the C-termini of ß-strands including the catalytic residues Glu204 and Glu388 (CIB12), and Glu204 and Glu385 (CIB13). Both enzymes preferred cellobiose over lactose as substrates and were classified as cellobiohydrolases. Cellobiose addition increased the biomass yield of Cuniculiplasma cultures growing on peptides by 50%, suggesting that the cellobiohydrolases expand the carbon substrate range and hence environmental fitness of Cuniculiplasma.

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The scarcity of cellulases with low ß-glucosidase activity poses a significant technological challenge in precisely controlling the partial hydrolysis of lignocellulose to cellobiose, crucial for producing high-value chemicals such as starch, inositol, and NMN. Trichoderma reesei is a primary strain in cellulase production. Therefore, this study targeted the critical ß-glucosidase gene, Trbgl1, resulting in over an 86 % reduction in ß-glucosidase activity. However, cellulase production decreased by 19.2 % and 20.3 % with lactose or cellulose inducers, respectively. Notably, transcript levels of cellulase genes and overall yield remained unaffected with an inducer containing sophorose. This indicates that ß-glucosidase BGL1 converts lactose or cellulose to sophorose through transglycosylation activity, inducing cellulase gene transcription. The resulting enzyme cocktail, comprising recombinant cellulase and cellobiose phosphorylase, was applied for corn stover hydrolysis, resulting in a 24.3 % increase in glucose-1-phosphate yield. These findings provide valuable insights into obtaining enzymes suitable for the high-value utilization of lignocellulose.

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The ß-glucosidases known to improve tea aroma are all mesothermal enzymes, limiting their use under brewing conditions. Based on the properties analysis and molecular docking, the thermostable ß-glucosidase (TPG) from Thermotoga petrophlia showed potential to enhance tea aroma. Treatment by recombinant TPG at 90 °C, the floral, sweet and grassy notes of instant Oolong tea were increased, while the roasted, caramel and woody notes were decreased. The improved floral, sweet and grassy notes were related to increase releasing of benzyl alcohol (floral), geraniol (floral), (Z)-3-hexen-1-ol (grassy), benzaldehyde (sweet) and 1-hexanol (grassy) by TPG hydrolyzing of (Z)-3-hexenyl-ß-D-glucopyranoside, hexanyl-ß-D-glucopyranoside (HGP), benzyl-ß-D-glucopyranoside, prunasin and geranyl-ß-D-glucopyranoside (GGP), respectively. Although the catalytic efficiency of TGP to GGP was about twice that to HGP, HPG was more competitive than GGP when they mixed. Combined with microstructure analysis, the structure-function relationship of TPG-influencing tea aroma were understood. This study provided the method of how to mining new function of characterized ß-glucosidases, as well as a theoretical basis for the development of new tea products.

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Trihydroxypiperidines are a therapeutically valuable class of iminosugar. We applied a one-pot amination-cyclisation cascade reaction to synthesise 3,4,5-trihydroxypiperidine stereoisomers in three steps from commercially available pentoses and in excellent overall yields. Using our methodology, the yields of the syntheses of meso-1, meso-2 and 3L are the highest reported to date. The synthetic methodology was readily extended to the three-step synthesis of N-alkyl derivatives by replacing the ammonia nitrogen source with a primary amine. The trihydroxypiperidines and N-alkyl analogues were screened for enzyme inhibitory activity using Fabrazyme (Fabry disease), GCase (Gaucher's disease), Agrobacterium sp. ß-glucosidase, and Escherichia coli ß-galactosidase. N-Phenylethyl 3,4,5-trihydroxypiperidine (N-phenylethyl-1-(3R,4R,5S)-piperidine-3,4,5-triol) showed good inhibitory activity of Fabrazyme (Ki = 46 µM). This activity was abolished when the N-phenylethyl group was removed or replaced with a non-aromatic alkyl chain.

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Processes of water retention and movement and the hydraulic conductivity are altered in the rhizosphere. The aim of this study was to investigate the physical-hydric properties of soil aggregates in the rhizosphere of annual ryegrass (Lolium multiflorum) cropped in a Kandiudalfic Eutrudox, taking into account aspects related to soil aggregate stability. Soil aggregates from rhizosphere soil (RZS) and soil between plant rows (SBP) were used to determine soil water retention curves (SWRCs) and saturated hydraulic conductivity (Ksat). In addition, properties related to soil aggregate stability, such as water-dispersible clay, soil organic carbon (SOC), and microbial activity, were also assessed. The higher microbial activity observed in the RZS was facilitated by increased SOC and microbial activity, resulting in improved soil aggregation (less water-dispersible clay). For nearly all measured matric potentials, RZS had a higher water content than SBP. This was attributed to the stability of aggregates, increase in SOC content, and the root exudates, which improved soil water retention. The increase in total porosity in RZS was associated with improved soil aggregation, which prevents deterioration of the soil pore space and results in higher Ksat and hydraulic conductivity as a function of the effective relative saturation in RZS compared to SBP.

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BACKGROUND: As promising biomarkers of diabetes, α-glucosidase (α-Glu) and ß-glucosidase (ß-Glu) play a crucial role in the diagnosis and management of diseases. However, there is a scarcity of techniques available for simultaneously and sensitively detecting both enzymes. What's more, most of the approaches for detecting α-Glu and ß-Glu rely on a single-mode readout, which can be affected by multiple factors leading to inaccurate results. Hence, the simultaneous detection of the activity levels of both enzymes in a single sample utilizing multiple-readout sensing approaches is highly attractive. RESULTS: In this work, we constructed a facile sensing platform for the simultaneous determination of α-Glu and ß-Glu by utilizing a luminescent covalent organic framework (COF) as a fluorescent indicator. The enzymatic hydrolysis product common to both enzymes, p-nitrophenol (PNP), was found to affect the fluorometric signal through an inner filter effect on COF, enhance the colorimetric response by intensifying the absorption peak at 400 nm, and induce changes in RGB values when analyzed using a smartphone-based color recognition application. By combining fluorometric/colorimetric measurements with smartphone-assisted RGB mode, we achieved sensitive and accurate quantification of α-Glu and ß-Glu. The limits of detection for α-Glu were determined to be 0.8, 1.22, and 1.85 U/L, respectively. Similarly, the limits of detection for ß-Glu were 0.16, 0.42, and 0.53 U/L, respectively. SIGNIFICANCE: Application of the proposed sensing platform to clinical serum samples revealed significant differences in the two enzymes between healthy people and diabetic patients. Additionally, the proposed sensing method was successfully applied for the screening of α-Glu inhibitors and ß-Glu inhibitors, demonstrating its viability and prospective applications in the clinical management of diabetes as well as the discovery of antidiabetic medications.

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ß-Glucosidase is a crucial cellulase, as its activity determines the efficiency of cellulose hydrolysis into glucose. This study addresses the functional and structural characteristics of Thermotoga profunda ß-glucosidase (Tp-BGL). Tp-BGL exhibited a Km of 0.3798 mM for p-nitrophenyl-ß-d-glucopyranoside (pNPGlc) and 4.44 mM for cellobiose, with kcat/Km of 1211.16 and 4.18 s-1 mM-1, respectively. In addition, Tp-BGL showed significant pH adaptability and thermal stability, with a Tm of 85.7 °C and retaining >90 % of its activity after incubation at 80 °C for 90 min. The crystal structure of Tp-BGL was resolved at 1.95 Å resolution, and reveals a typical TIM barrel structure. Comparative structural analysis highlighted that the major distinction between Tp-BGL and the other glucosidases lies in their loop regions.

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The high temperature induces conformational changes in ß-glucosidase, making it inactive and limiting its application field. In this paper, the effect of trehalose on the thermostability of ß-glucosidase from low-moisture Hevea brasiliensis seeds was investigated. The results showed that the residual enzyme activities of ß-glucosidase supplemented with trehalose after high-temperature treatment were significantly higher than that of the control group. The improvement of thermostability could be explained by low-field nuclear magnetic resonance (LF-NMR) and molecular dynamics (MD) simulations at the molecular level. Moreover, adding trehalose increased the water activity and water content of ß-glucosidase, leading to a more stable conformation. Trehalose replaced some water and formed a stable network of hydrogen bonds with protein and surrounding water. The glass formed by trehalose also reduced molecular movement, thus providing good protection for enzymes.

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Abscisic acid (ABA) plays a crucial role in plant defense mechanisms under adverse environmental conditions, but its metabolism and perception in response to heavy metals are largely unknown. In Pisum sativum exposed to CdCl2, an accumulation of free ABA was detected in leaves at different developmental stages (A, youngest, unexpanded; B1, youngest, fully expanded; B2, mature; C, old), with the highest content found in A and B1 leaves. In turn, the content of ABA conjugates, which was highest in B2 and C leaves under control conditions, increased only in A leaves and decreased in leaves of later developmental stages after Cd treatment. Based on the expression of PsNCED2, PsNCED3 (9-cis-epoxycarotenoid dioxygenase), PsAO3 (aldehyde oxidase) and PsABAUGT1 (ABA-UDP-glucosyltransferase), and the activity of PsAOγ, B2 and C leaves were found to be the main sites of Cd-induced de novo synthesis of ABA from carotenoids and ABA conjugation with glucose. In turn, ß-glucosidase activity and the expression of genes encoding ABA receptors (PsPYL2, PsPYL4, PsPYL8, PsPYL9) suggest that in A and B1 leaves, Cd-induced release of ABA from inactive ABA-glucosyl esters and enhanced ABA perception comes to the forefront when dealing with Cd toxicity. The distinct role of leaves at different developmental stages in defense against the harmful effects of Cd is discussed.

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In order to more efficiently utilize the abundant cellulose resources in nature, increase the utilization rate of cellulose in aquaculture, implement precise feeding and save aquaculture costs, we have conducted research on cellulase genes related to the spotted knifejaw (Oplegnathus punctatus). Cellulose, as the most abundant renewable resource, is a cornerstone in the intricate ecological balance of diverse ecosystems. While herbivorous fish are recognized for their utilization of proteins, sugars, and fats, the extent of cellulose utilization by carnivorous and omnivorous fish remains an enigma. Here, through field sampling and behavioural observations, O. punctatus' omnivorous diet has been demonstrated (stomach contents contain approximately several species of algae in the Bacillariophyta (1.12 %), Streptomyces (0.55 %), Chlorophyta (0.35 %), Rhodophyta (0.16 %), and Euglenophyta (0.19 %) phylum). Additionally, the high cellulase activity in the intestine of O. punctatus has been detected first discovery (enzyme activity up to 4800.15 U/g), indicating its ability to digest cellulose. By employing whole-genome scanning and high-throughput sequencing, a single cellulase gene (ß-glucosidase) within the genome of O. punctatus, suggesting the absence of a complete cellulose digestive system. However, microbiological analysis revealed the three crucial role of microorganisms, including Actinobacteria (25.80 %), Bacteroidetes (18.93 %), and Firmicutes phylum (0.82 %), were found to play a crucial role in the decomposition of plant cell walls, thereby facilitating plant material digestion to help the host to complete the process of cellulose digestion. Expression patterns and proteomic analysis of the ß-glucosidase were notably high in the gonads. In situ hybridization confirmed the expression of the ß-glucosidase gene in the intestinal contents and gonads, highlighting its role in supplying energy of gonads. These discoveries shed light on the dietary habits of O. punctatus and its cellulose utilization, offering insights that can inform the development of customized feeding strategies to enhance aquaculture sustainability and minimize resource expenditure.

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The novel ß-glucosidase gene (pgbgl1) of glycoside hydrolase (GH) family 1 from the psychrotrophic bacterium Psychrobacillus glaciei sp. PB01 was successfully expressed in Escherichia coli BL21 (DE3). The deduced PgBgl1 contained 447 amino acid residues with a calculated molecular mass of 51.4 kDa. PgBgl1 showed its maximum activity at pH 7.0 and 40 °C, and still retained over 10% activity at 0 °C, suggesting that the recombinant PgBgl1 is a cold-adapted enzyme. The substrate specificity, Km, Vmax, and Kcat/Km for the p-Nitrophenyl-ß-D-glucopyranoside (pNPG) as the substrate were 1063.89 U/mg, 0.36 mM, 1208.31 U/mg and 3871.92/s, respectively. Furthermore, PgBgl1 demonstrated remarkable stimulation of monosaccharides such as glucose, xylose, and galactose, as well as NaCl. PgBgl1 also demonstrated a high capacity to convert the primary soybean isoflavone glycosides (daidzin, genistin, and glycitin) into their respective aglycones. Overall, PgBgl1 exhibited high catalytic activity towards aryl glycosides, suggesting promising application prospects in the food, animal feed, and pharmaceutical industries.

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A Gram-stain-positive actinomycete, designated REN17T, was isolated from fermented grains of Baijiu collected from Sichuan, PR China. It exhibited branched substrate mycelia and a sparse aerial mycelium. The optimal growth conditions for REN17T were determined to be 28 °C and pH 7, with a NaCl concentration of 0 % (w/v). ll-Diaminopimelic acid was the diagnostic amino acid of the cell-wall peptidoglycan and the polar lipids were composed of phosphatidylethanolamine, phosphatidylinositol, an unidentified phospholipid, two unidentified lipids and four unidentified glycolipids. The predominant menaquinone was MK-9 (H2), MK-9 (H4), MK-9 (H6) and MK-9 (H8). The major fatty acids were iso-C16 : 0. The 16S rRNA sequence of REN17T was most closely related to those of Streptomyces apricus SUN 51T (99.8 %), Streptomyces liliiviolaceus BH-SS-21T (99.6 %) and Streptomyces umbirnus JCM 4521T (98.9 %). The digital DNA-DNA hybridization, average nucleotide identity and average amino acid identify values between REN17T and its closest replated strain, of S. apricus SUN 51T, were 35.9, 88.9 and 87.3 %, respectively. Therefore, REN17T represents a novel species within the genus Streptomyces, for which the name Streptomyces beigongshangae sp. nov. is proposed. The type strain is REN17T (=GDMCC 4.193T=JCM 34712T). While exploring the function of the strain, REN17T was found to possess the ability to transform major ginsenosides of Panax notoginseng (Burk.) F.H. Chen (Araliaceae) into minor ginsenoside through HPLC separation, which was due to the presence of ß-glucosidase. The recombinant ß-glucosidase was constructed and purified, which could produce minor ginsenosides of Rg3 and C-K. Finally, the enzymatic properties were characterized.

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ß-glucosidase hydrolyses the glycosidic bonds in cellobiose and cello-oligosaccharides, a critical step in the saccharification for biofuel production. Hence, the aim of this study was to gain insights into the biochemical and structural properties of a ß-glucosidase from Beauveria bassiana, an entomopathogenic fungus. The ß-glucosidase was purified to homogeneity using salt precipitation, ultrafiltration, and chromatographic techniques, attaining a specific activity of 496 U/mg. The molecular mass of the enzyme was then estimated via SDS-PAGE to be 116 kDa, while its activity pattern was confirmed by zymography using 4-methylumbelliferyl-ß-d-glucopyranoside. Furthermore, the pH optima and temperature of the enzyme were found to be pH 5.0 and 60 °C respectively; its activity was significantly enhanced by Mg2+ and Na+ and was found to be relatively moderate in the presence of ethanol and dichloromethane. Molecular docking of the modelled B. bassiana ß-glucosidase structure with the substrates, viz., 4-nitrophenyl ß-d-glucopyranoside and cellobiose, revealed the binding affinity energies of -7.2 and -6.2 (kcal mol-1), respectively. Furthermore, the computational study predicted Lys-657, Asp-658, and Arg-1000 as the core amino acid residues in the catalytic site of the enzyme. This is the first investigation into a purified ß-glucosidase from B. bassiana, providing valuable insights into the functional properties of carbohydrases from entomopathogenic fungal endophytes.

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Hamelia patens (Rubiaceae), known as firebush, is a source of bioactive monoterpenoid oxindole alkaloids (MOAs) derived from monoterpenoid indole alkaloids (MIAs). With the aim of understanding the regulation of the biosynthesis of these specialized metabolites, micropropagated plants were elicited with jasmonic acid (JA) and salicylic acid (SA). The MOA production and MIA biosynthetic-related gene expression were evaluated over time. The production of MOAs was increased compared to the control up to 2-fold (41.3 mg g DW-1) at 72 h in JA-elicited plants and 2.5-fold (42.4 mg g DW-1) at 120 h in plants elicited with SA. The increment concurs with the increase in the expression levels of the genes HpaLAMT, HpaTDC, HpaSTR, HpaNPF2.9, HpaTHAS1, and HpaTHAS2. Interestingly, it was found that HpaSGD was downregulated in both treatments after 24 h but in the SA treatment at 120 h only was upregulated to 8-fold compared to the control. In this work, we present the results of MOA production in H. patens and discuss how JA and SA might be regulating the central biosynthetic steps that involve HpaSGD and HpaTHAS genes.

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This study aims to utilize the microbial resources found within Laphet-so, a traditional fermented tea in Myanmar. A total of 18 isolates of thermotolerant yeasts were obtained from eight samples of Laphet-so collected from southern Shan state, Myanmar. All isolates demonstrated the tannin tolerance, and six isolates were resistant to 5% (w/v) tannin concentration. All 18 isolates were capable of carboxy-methyl cellulose (CMC) degrading, but only the isolate DK showed ethanol production at 45 °C noticed by gas formation. This ethanol producing yeast was identified to be Cyberlindnera rhodanensis based on the sequence analysis of the D1/D2 domain on rRNA gene. C. rhodanensis DK produced 1.70 ± 0.01 U of thermostable extracellular ß-glucosidase when cultured at 37 °C for 24 h using 0.5% (w/v) CMC as a carbon source. The best two carbon sources for extracellular ß-glucosidase production were found to be either xylose or xylan, with ß-glucosidase activity of 3.07-3.08 U/mL when the yeast was cultivated in the yeast malt extract (YM) broth containing either 1% (w/v) xylose or xylan as a sole carbon source at 37 °C for 48 h. The optimal medium compositions for enzyme production predicted by Plackett-Burman design and central composite design (CCD) was composed of yeast extract 5.83 g/L, peptone 10.81 g/L and xylose 20.20 g/L, resulting in a production of 7.96 U/mL, while the medium composed (g/L) of yeast extract 5.79, peptone 13.68 and xylan 20.16 gave 9.45 ± 0.03 U/mL for 48 h cultivation at 37 °C. Crude ß-glucosidase exhibited a remarkable stability of 100%, 88% and 75% stable for 3 h at 35, 45 and 55 °C, respectively.

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As a crucial enzyme for cellulose degradation, ß-glucosidase finds extensive applications in food, feed, and bioethanol production; however, its potential is often limited by inadequate thermal stability and glucose tolerance. In this study, a functional gene (lq-bg5) for a GH1 family ß-glucosidase was obtained from the metagenomic DNA of a hot spring sediment sample and heterologously expressed in E. coli and the recombinant enzyme was purified and characterized. The optimal temperature and pH of LQ-BG5 were 55 °C and 4.6, respectively. The relative residual activity of LQ-BG5 exceeded 90% at 55 °C for 9 h and 60 °C for 6 h and remained above 100% after incubation at pH 5.0-10.0 for 12 h. More importantly, LQ-BG5 demonstrated exceptional glucose tolerance with more than 40% activity remaining even at high glucose concentrations of 3000 mM. Thus, LQ-BG5 represents a thermophilic ß-glucosidase exhibiting excellent thermal stability and remarkable glucose tolerance, making it highly promising for lignocellulose development and utilization.

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