Biotransformation of Protopanaxadiol-Type Ginsenosides in Korean Ginseng Extract into Food-Available Compound K by an Extracellular Enzyme from Aspergillus niger

Enhanced production of ginsenoside compound K by synergistic conversion of fermentation with Aspergillus tubingensis and commercial cellulase

Fermentation of ginseng extract is limited by the low concentration of compound K (CK), a bioactive ginsenoside. In this study, a novel approach combining Aspergillus tubingensis fermentation with Aspergillus niger cellulase conversion was used to enhance CK production from high concentrations of American ginseng extract (AGE). The reaction conditions, including the feeding rate and concentrations of carbon source, enzyme type, AGE and enzyme concentrations, temperature, pH, and timing of enzyme addition, were optimized. Under optimized conditions, this combined method achieved an enhanced CK production of 8.06 g/L (13.0 mM) after 168 h, with a productivity of 48 mg/L/h. This approach led to a 2.0-fold increase in concentration and a 1.7-fold increase in productivity when compared with traditional fermentation using the same strain. The findings of this study demonstrate the synergistic effect of combining fermentation with enzyme conversion to improve CK production.

Transcriptome Profiling, Cloning, and Characterization of AnGlu04478, a Ginsenoside Hydrolyzing β-Glucosidase from Aspergillus niger NG1306

β-Glucosidase plays a pivotal role in transforming ginsenosides into specific minor ginsenosides. In this study, total ginsenosides from Panax notoginseng leaves were used as substrates to stimulate the growth of Aspergillus niger NG1306. Transcriptome analysis identified a β-glucosidase gene, Anglu04478 (1455 bp, 484 amino acids, 54.5 kDa, pI = 5.1), as a participant in the ginsenosides biotransformation process. This gene was cloned and expressed in Escherichia coli BL21 Transetta (DE3). The AnGlu04478 protein was purified using a Ni2+ column, and its enzymatic properties were characterized. Purified AnGlu04478 exhibited a specific activity of 32.97 U/mg when assayed against pNPG. Under optimal conditions (pH 4.5, temperature 40 °C), the kinetic parameters, Km and Vmax, for pNPG were 1.55 mmol/L and 0.014 mmol/min, respectively. Cu2+ displayed an inhibitory effect on AnGlu04478, whereas Ca2+, Co2+, and Ni2+ ions had minimal impact. The enzyme showed tolerance to ethanol and was largely unaffected by glucose feedback inhibition. Testing with ginsenosides as substrates revealed selective hydrolysis at the C3 position of ginsenosides Rb1, Rb2, Rb3, and Rc, with the metabolic pathway delineated as Rb1 → GypXVII, Rb2 → C-O, Rb3 → C-Mx1 → C-Mx, and Rc → C-Mc1. The conversion rates of ginsenosides Rb1, Rb2, Rb3, and Rc varied from 2.58 to 20.63%. With 0.5 U purified enzyme and 0.5 mg total ginsenosides, incubated at 40 °C for 12 h, the conversion rates were 42.6% for GypXVII, 10.4% for C-O, 6.27% for C-Mx1, 26.96% for C-Mx, and 90% for Rc. These results suggest that AnGlu04478 displays substrate promiscuity as a β-glucosidase, thus broadening the potential for ginsenoside biotransformation.

Cloning, characterization of β-glucosidase from Furfurilactobacillus rossiae in bioconversion and its efficacy

Minor ginsenosides produced by β-glucosidase are interesting biologically and pharmacologically. In this study, new ginsenoside-hydrolyzing glycosidase from Furfurilactobacillus rossiae DCYL3 was cloned and expressed in Escherichia coli strain BL21. The enzyme converted Rb1 and Gyp XVII into Rd and compound K following the pathways: Rb1→Rd and Gyp XVII→F2→CK, respectively at optimal condition: 40 °C, 15 min, and pH 6.0. Furthermore, we examined the cytotoxicity, NO production, ROS generation, and gene expression of Gynostemma extract (GE) and bioconverted Gynostemma extract (BGE) in vitro against A549 cell lines for human lung cancer and macrophage RAW 264.7 cells for antiinflammation, respectively. As a result, BGE demonstrated significantly greater toxicity than GE against lung cancer at a dose of 500 µg/mL but in normal cells showed lower toxicity. Then, we indicated an enhanced generation of ROS, which may be boosting cancer cell toxicity. By blocking the intrinsic way, BGE increased p53, Bax, Caspase 3, 9, and while Bcl2 is decreased. At 500 µg/mL, the BGE sample was less toxic in normal cells and decreased the LPS-treated NO and ROS level to reduce inflammation. In addition, BGE inhibited the expression of pro-inflammatory genes COX-2, iNOS, IL-6, and IL-8 in RAW 264.7 cells than the sample of GE. In conclusion, FrBGL3 has considerable downstream applications for high-yield, low-cost, effective manufacture of minor ginsenosides. Moreover, the study's findings imply that BGE would be potential materials for anti-cancer and anti-inflammatory agent after consideration of future studies.

Advancements in enzymatic biotransformation and bioactivities of rare ginsenosides: A review

Ginsenoside, the principal active constituent of ginseng, exhibits enhanced bioavailability and medicinal efficacy in rare ginsenosides compared to major ginsenosides. Current research is focused on efficiently and selectively removing sugar groups attached to the major ginsenoside sugar chains to convert them into rare ginsenosides that meet the demands of medical industry and functional foods. The methods for preparing rare ginsenosides encompass chemical, microbial, and enzymatic approaches. Among these, the enzyme conversion method is highly favored by researchers due to its exceptional specificity and robust efficiency. This review summarizes the biological activities of different rare ginsenosides, explores the various glycosidases used in the biotransformation of different major ginsenosides as substrates, and elucidates their respective corresponding biotransformation pathways. These findings will provide valuable references for the development, utilization, and industrial production of ginsenosides.

Gypenoside biotransformation into ginsenoside F2 by endophytic Aspergillus niger from Gynostemma pentaphyllum

Ginsenoside F2 is a protopanaxadiol saponin compound with various biological activities, including antioxidant, anti-inflammatory, and anticancer properties. Ginsenoside F2 can be found in ginseng, but in low quantities. Therefore, ginsenoside F2 production predominantly relies on the biotransformation of various ginsenosides, such as ginsenosides Rb1 and Rd. In this study, we reported the production of ginsenoside F2 by gypenoside biotransformation with Aspergillus niger JGL8, isolated from Gynostemma pentaphyllum. Ginsenoside F2 could be produced by two different biotransformation pathways, namely Gyp-V-Rd-F2 and Gyp-XVII-F2. The product exhibited antioxidant activity against free radicals (DPPH) with IC50 value of 29.54 µg/mL. Optimal biotransformation conditions were a pH of 5.0, temperature of 40 °C, and 2 mg/mL of substrate. Enzyme kinetic parameters revealed that the hydrolysis rate of Gyp-V, Rd, and Gyp-XVII was 0.625, 0.588, and 0.417 mM/h, respectively. In conclusion, we demonstrated that gypenoside is a substitutable substrate for ginsenoside F2 biotransformation.

Biodegradation mechanism of chlorpyrifos by Bacillus sp. H27: Degradation enzymes, products, pathways and whole genome sequencing analysis

Chlorpyrifos (CP) is a pesticide widely used in agricultural production. However, excessive use of CP is risky for human health and the ecological environment. Microbial remediation has become a research hotspot of environmental pollution control. In this study, the effective CP-degrading strain H27 (Bacillus cereus) was screened from farmland soil, and the degradation ratio was more than 80%. Then, the degradation mechanism was discussed in terms of enzymes, pathways, products and genes, and the mechanism was improved in terms of cell motility, secretory transport system and biofilm formation. The key CP-degrading enzymes were mainly intracellular enzymes (IE), and the degradation ratio reached 49.6% within 30 min. The optimal pH for IE was 7.0, and the optimal temperature was 25 °C. Using DFT and HPLC‒MS analysis, it was found that degradation mainly involved oxidation, hydrolysis and other reactions, and 3 degradation pathways and 14 products were identified, among which TCP (3,5,6-trichloro-2-pyridinol) was the main primary degradation product in addition to small molecules such as CO2 and H2O. Finally, the whole genome of strain H27 was sequenced, and the related degrading genes and enzymes were investigated to improve the metabolic pathways. Strain H27 had perfect genes related to flagellar assembly and chemotaxis and tended to tolerate CP. Moreover, it can secrete esterase, phosphatase and other substances, which can form biofilms and degrade CP in the environment. In addition, CP enters the cell under the action of permeases or transporters, and it is metabolized by IE. The degradation mechanism of CP by strain H27 is speculated in this study, which provided a theoretical basis for enriching CP-degrading bacteria resources, improving degradation metabolic pathways and mechanisms, and applying strain H27 to environmental pollution remediation.

Cerium oxide nanoparticles: Synthesis methods and applications in wound healing

Wound care and treatment can be critical from a clinical standpoint. While different strategies for the management and treatment of skin wounds have been developed, the limitations inherent in the current approaches necessitate the development of more effective alternative strategies. Advances in tissue engineering have resulted in the development of novel promising approaches for accelerating wound healing. The use of various biomaterials capable of accelerating the regeneration of damaged tissue is critical in tissue engineering. In this regard, cerium oxide nanoparticles (CeO2 NPs) have recently received much attention because of their excellent biological properties, such as antibacterial, anti-inflammatory, antioxidant, and angiogenic features. The incorporation of CeO2 NPs into various polymer-based scaffolds developed for wound healing applications has led to accelerated wound healing due to the presence of CeO2 NPs. This paper discusses the structure and functions of the skin, the wound healing process, different methods for the synthesis of CeO2 NPs, the biological properties of CeO2 NPs, the role of CeO2 NPs in wound healing, the use of scaffolds containing CeO2 NPs for wound healing applications, and the potential toxicity of CeO2 NPs.

Production of ginsenoside compound K from American ginseng extract by fed-batch culture of Aspergillus tubingensis

Compound K (C-K), one of the most bioactive ginsenoside, is produced by hydrolyzing the glycoside moieties of protopanaxadiol (PPD)-type glycosylated ginsenosides in the ginseng extract. To enhance the biotransformation of PPD-type ginsenosides in American ginseng extract (AGE) into C-K, the optimization of the feed type, concentration, and period for the carbon source sucrose and the reactant AGE was performed in fed-batch fermentation of Aspergillus tubingensis using a fermenter. The concentration (3.94 g/L) and productivity (27.4 mg/L/h) of C-K after feed optimization in fed-batch fermentation increased 3.1-fold compared to those (1.29 g/L and 8.96 mg/L/h) in batch fermentation, and a molar conversion of 100% was achieved. To the best of our knowledge, this is the first trial of fed-batch fermentation to convert ginseng extract into deglycosylated ginsenoside and the highest reported C-K concentration and productivity using ginseng extract via fermentation. After ethanol and resin treatments, C-K solids with purities of 59% and 96% were obtained from the fermentation broth as food- and pharmaceutical-grade products, respectively.

β-Glucosidase and Its Application in Bioconversion of Ginsenosides in Panax ginseng

Ginsenosides are a group of bioactive compounds isolated from Panax ginseng. Conventional major ginsenosides have a long history of use in traditional medicine for both illness prevention and therapy. Bioconversion processes have the potential to create new and valuable products in pharmaceutical and biological activities, making them both critical for research and highly economic to implement. This has led to an increase in the number of studies that use major ginsenosides as a precursor to generate minor ones using β-glucosidase. Minor ginsenosides may also have useful properties but are difficult to isolate from raw ginseng because of their scarcity. Bioconversion processes have the potential to create novel minor ginsenosides from the more abundant major ginsenoside precursors in a cost-effective manner. While numerous bioconversion techniques have been developed, an increasing number of studies have reported that β-glucosidase can effectively and specifically generate minor ginsenosides. This paper summarizes the probable bioconversion mechanisms of two protopanaxadiol (PPD) and protopanaxatriol (PPT) types. Other high-efficiency and high-value bioconversion processes using complete proteins isolated from bacterial biomass or recombinant enzymes are also discussed in this article. This paper also discusses the various conversion and analysis methods and their potential applications. Overall, this paper offers theoretical and technical foundations for future studies that will be both scientifically and economically significant.

Biotransformation of Platycosides, Saponins from Balloon Flower Root, into Bioactive Deglycosylated Platycosides

Platycosides, saponins from balloon flower root (Platycodi radix), have diverse health benefits, such as antioxidant, anti-inflammatory, anti-tussive, anti-cancer, anti-obesity, anti-diabetes, and whitening activities. Deglycosylated platycosides, which show greater biological effects than glycosylated platycosides, are produced by the hydrolysis of glycoside moieties in glycosylated platycosides. In this review, platycosides are classified according to the chemical structures of the aglycone sapogenins and also divided into natural platycosides, including major, minor, and rare platycosides, depending on the content in Platycodi radix extract and biotransformed platycosides. The biological activities of platycosides are summarized and methods for deglycosylation of saponins, including physical, chemical, and biological methods, are introduced. The biotransformation of glycosylated platycosides into deglycosylated platycosides was described based on the hydrolytic pathways of glycosides, substrate specificity of glycosidases, and specific productivities of deglycosylated platycosides. Methods for producing diverse and/or new deglycosylated platycosides are also proposed.

Upgrading the accumulation of ginsenoside Rd in Panax notoginseng by a novel glycosidase-producing endophytic fungus G11-7

A novel endophytic fungus producing beta-glucosidase was isolated and characterized from pigeon pea (Cajanus cajan [L.] Millsp.), which has excellent properties in converting ginsenoside Rb1 to ginsenoside Rd in Panax notoginseng. According to the 16S rDNA gene sequence, the G11-7 strain was identified as Fusarium proliferatum, and the accession number KY303906 was confirmed in GenBank. The G11-7 immobilized spores, in which the activity of beta-glucosidase could reach 0.95 U/mL, were co-cultured with P. notoginseng plant material to obtain a continuous beta-glucosidase supply for the biotransformation of ginsenoside Rb1 to Rd. Under the liquid-solid ratio (20:1), initial pH (6.0), and temperature (30 °C) constituents, the maximum ginsenoside Rd yield was obtained as 9.15 ± 0.65 mg/g, which was 3.67-fold higher than that without fungal spore co-culture (2.49 ± 0.98 mg/g). Furthermore, immobilized G11-7 spores showed significant beta-glucosidase producing ability which could be recovered and reused for 6 cycles. Overall, these results suggested that immobilized G11-7 offered a promising and effective approach to enhance the production of ginsenoside Rd for possible nutraceutical and pharmaceutical uses.

Production of Minor Ginsenoside CK from Major Ginsenosides by Biotransformation and Its Advances in Targeted Delivery to Tumor Tissues Using Nanoformulations

For over 2000 years, ginseng (roots of Panax ginseng C.A. Meyer) has been used as a traditional herbal medicine. Ginsenosides are bioactive compounds present in ginseng responsible for the pharmacological effects and curing various acute diseases as well as chronic diseases including cardiovascular disease, cancer and diabetes. Structurally, ginsenosides consist of a hydrophobic aglycone moiety fused with one to four hydrophilic glycoside moieties. Based on the position of sugar units and their abundance, ginsenosides are classified into major and minor ginsenosides. Despite the great potential of ginsenosides, major ginsenosides are poorly absorbed in the blood circulation, resulting in poor bioavailability. Interestingly, owing to their small molecular weight, minor ginsenosides exhibit good permeability across cell membranes and bioavailability. However, extremely small quantities of minor ginsenosides extracted from ginseng plants cannot fulfill the requirement of scientific and clinical studies. Therefore, the production of minor ginsenosides in mass production is a topic of interest. In addition, their poor solubility and lack of targetability to tumor tissues limits their application in cancer therapy. In this review, various methods used for the transformation of major ginsenosides to minor ginsenoside compound K (CK) are summarized. For the production of CK, various transformation methods apply to major ginsenosides. The challenges present in these transformations and future research directions for producing bulk quantities of minor ginsenosides are discussed. Furthermore, attention is also paid to the utilization of nanoformulation technology to improve the bioavailability of minor ginsenoside CK.

Structural characterization and anti-inflammatory properties of green synthesized chitosan/compound K‑gold nanoparticles

Ginsenoside compound K (CK) has been shown to exhibit anti-inflammatory properties. In this study, to encourage biomedical applications of biosynthesized gold nanoparticles (AuNPs) with anti-inflammatory effects, AuNPs loaded with ginsenoside compound K were prepared using a self-assembly technique with chitosan as the carrier. Optimal conditions for chitosan-ginsenoside CK‑gold nanoparticles (CS-CK-AuNPs) formation were monitored using UV-Vis absorption spectroscopy. The physicochemical characterization of CS-CK-AuNPs was performed using FE-TEM, FE-SEM, XRD, DLS, FTIR and NMR techniques. In the stability test, CS-CK-AuNPs did not show any significant changes up to 4 weeks. Fluorescence imaging demonstrated that CS-CK-AuNPs promoted cellular uptake in vitro, but did not exhibit significant cytotoxicity at concentrations below 40 μg/mL. Additionally, the CS-CK-AuNPs inhibited NO production, and reduced the expression and secretion of inflammatory cytokines (IL-1β, IL-6, and TNF-α) via inhibition of the nuclear factor-kappaB (NF-κB) pathway in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Thus, CS-CK-AuNPs are novel candidates for developing anti-inflammatory agent. This study also confirms the superiority of chitosan AuNPs as oral delivery vehicles for inflammation-related diseases.

Increased Production of Ginsenoside Compound K by Optimizing the Feeding of American Ginseng Extract during Fermentation by Aspergillus tubingensis

The ginsenoside compound K (C-K) is widely used in traditional medicines, nutritional supplements, and cosmetics owing to its diverse pharmacological activities. Although many studies on C-K production have been conducted, fermentation is reported to produce C-K with low concentration and productivity. In the present study, addition of an inducer and optimization of the carbon and nitrogen sources in the medium were performed using response surface methodology to increase the C-K production via fermentation by Aspergillus tubingensis, a generally recognized as safe fungus. The optimized inducer and carbon and nitrogen sources were 2 g/l rice straw, 10 g/l sucrose, and 10 g/l soy protein concentrate, respectively, and they resulted in a 3.1-fold increase in the concentration and productivity of C-K (0.22 g/l and 1.52 mg/l/h, respectively) compared to those used before optimization without inducer (0.071 g/l and 0.49 mg/l/h, respectively). The feeding methods of American ginseng extract (AGE), including feeding timing, feeding concentration, and feeding frequency, were also optimized. Under the optimized conditions, A. tubingensis produced 3.96 mM (2.47 g/l) C-K at 144 h by feeding two times with 8 g/l AGE at 48 and 60 h, with a productivity of 17.1 mg/l/h. The concentration and productivity of C-K after optimization of feeding methods were 11-fold higher than those before the optimization (0.22 g/l and 1.52 mg/l/h, respectively). Thus, the optimization for the feeding methods of ginseng extract is an efficient strategy to increase C-K production. To our knowledge, this is the highest reported C-K concentration and productivity via fermentation reported so far.

A Novel Endo-Polygalacturonase from Penicillium oxalicum: Gene Cloning, Heterologous Expression and Its Use in Acidic Fruit Juice Extraction

An endo-polygalacturonase (endo-PGase) exhibiting excellent performance during acidic fruit juice production would be highly attractive to the fruit juice industry. However, candidate endo-PGases for this purpose have rarely been reported. In this study, we expressed a gene from Penicillium oxalicum in Pichia pastoris. The recombinant enzyme PoxaEnPG28C had an optimal enzyme activity at pH 4.5 and 45°C and was stable at pH 3.0-6.5 and < 45°C. The enzyme had a specific activity of 4,377.65 ± 55.37 U/mg towards polygalacturonic acid, and the K_m and V_max values of PoxaEnPG28C were calculated as 1.64 g/l and 6127.45 U/mg, respectively. PoxaEnPG28C increased the light transmittance of orange, lemon, strawberry and hawthorn juice by 13.9 ± 0.3%, 29.4 ± 3.8%, 95.7 ± 10.2% and 79.8 ± 1.7%, respectively; it reduced the viscosity of the same juices by 25.7 ± 1.6%, 52.0 ± 4.5%, 48.2 ± 0.7% and 80.5 ± 2.3%, respectively, and it increased the yield of the juices by 24.5 ± 0.7%, 12.7 ± 2.2%, 48.5 ± 4.2% and 104.5 ± 6.4%, respectively. Thus, PoxaEnPG28C could be considered an excellent candidate enzyme for acidic fruit juice production. Remarkably, fruit juice production using hawthorn as an material was reported for the first time.

Production of Deglucose-Apiose-Xylosylated Platycosides from Glycosylated Platycosides by Crude Enzyme from Aspergillus tubingensis

Platycosides, Platycodi radix (Platycodon grandiflorus root) saponins, are used as food supplements and exert diverse pharmacological activities. Deglycosylation of saponins enhances their biological efficacy, and deglycosylated platycosides are produced mainly through enzymatic hydrolysis. However, the types of available deglycosylated platycosides remain limited because of a lack of hydrolyzing enzymes that can act on specific glycosides in glycosylated platycosides. In this study, a crude enzyme from Aspergillus tubingensis converted platycoside E (PE) and polygalacin D₃ (PGD3) into deglucose-apiose-xylosylated (deGAX)-platycodin D (PD) and deGAX-polygalacin D (PGD), respectively. The products were identified through LC/MS analysis by specifically hydrolyzing all glucose residues at C-3, and apiose and xylose residues at C-28 of platycoside. The hydrolytic activity of the crude enzyme obtained after the cultivation of the fungus using citrus pectin and corn steep solid as carbon and nitrogen sources, respectively, in culture medium was increased compared with those using other carbon and nitrogen sources. The crude enzyme from A. tubingensis was the most effective in producing deGAX platycoside at pH 5.0 and 60°C. The crude enzyme produced 0.32 mg/ml deGAX-PD and 0.34 mg/ml deGAX-PGD from 1 mg/ml PE and 1 mg/ml PGD3 (at pH 5.0 and 60°C) for 12 and 10 h, with productivities of 32.0 and 42.5 mg/l/h and molar yields of 62.1 and 59.6%, respectively. To the best of our knowledge, this is the first study to produce deGAX platycosides from glycosylated platycosides.

Enhanced biotransformation of the minor ginsenosides in red ginseng extract by Penicillium decumbens β-glucosidase

Compound K (C-K) and Rh2, which are present at low levels in ginseng and ginseng extracts, have higher intestinal absorption rates than other ginsenosides. Here, we attempted to convert ginsenoside Rb1 to C-K using a β-glucosidase from Penicillium decumbens. Ten commercially available enzymes were screened to identify enzymes that can convert ginsenoside Rb1 to C-K, resulting in the selection of a P. decumbens-derived β-glucosidase. β-Glucosidase showed maximum activity at pH 4.0 and 60 °C; its substrate specificity for ginsenoside Rb1 was investigated. The main glucoside-hydrolyzing pathways were as follows: ginsenoside Rb1 or Rd → gypenoside XVII → F2 → C-K and ginsenoside Rg3 → Rh2. The P. decumbens-derived β-glucosidase was used to generate C-K and Rh2 using protopanaxadiol-type ginsenosides as substrates. Additionally, to apply this enzyme to the commercialized red ginseng extract products, the contents of C-K and Rh2 in the total ginsenosides significantly (p < 0.05) increased up to 36-fold and 8.9-fold, respectively, higher than prior to subjecting to biotransformation. To the best of our knowledge, this is the first report of the dual biotransformation of C-K and Rh2 by a food-grade commercial enzyme. This study demonstrates that the use of a specific β-glucosidase may increase C-K and Rh2 contents in the ginseng extract through a simple biotransformation process and, thus, enhance its health benefits.

In Vitro Evaluation of Anti-Lung Cancer and Anti-COVID-19 Effects using Fermented Black Color Ginseng Extract

Ginseng is known as the “king” of herbal plants and has been used widely in Asia for centuries. Ginseng contains active saponins, including protopanaxadiols, protopanaxatriols, and other compounds. There are many methods for processing ginseng, such as steaming, fermentation, expansion, and conversion of active compounds, which can improve its biological activity. In this study, we investigated the cytotoxic and oxidative effects of fermented black color ginseng (FBCG), black ginseng (BG), and white ginseng (WG) on a human lung carcinoma cell line (A549). Moreover, we found that treatment with FBCG induced oxidative stress in the A549 cell line and increases the apoptosis percentage; these effects were linked to the stimulation of the caspase 3/mitogen-activated protein kinase (caspase 3/MAPK) pathway. We also evaluated the anti-coronavirus disease-2019 (COVID-19) effect of FBCG on a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected Vero E6 cell line. Our results suggest that FBCG not only inhibits the replication of this strain of virus in the cell but also reduces the number of viral RNA (vRNA) copies in the extracellular environment. Taken together, these data show that FBCG has both potential anti-lung cancer and anti-COVID-19 effects.

Interspecific evolutionary relationships of alpha-glucuronidase in the genus Aspergillus

The increased availability and production of lignocellulosic agroindustrial wastes has originated proposals for their use as raw material to obtain biofuels (ethanol and biodiesel) or derived products. However, for biomass generated from lignocellulosic residues to be successfully degraded, in most cases it requires a physical (thermal), chemical, or enzymatic pretreatment before the application of microbial or enzymatic fermentation technologies (biocatalysis). In the context of enzymatic technologies, fungi have demonstrated to produce enzymes capable of degrading polysaccharides like cellulose, hemicelluloses and pectin. Because of this ability for degrading lignocellulosic material, researchers are making efforts to isolate and identify fungal enzymes that could have a better activity for the degradation of plant cell walls and agroindustrial biomass. We performed an in silico analysis of alpha-glucoronidase in 82 accessions of the genus Aspergillus. The constructed dendrograms of amino acid sequences defined the formation of 6 groups (I, II, III, IV, V, and VI), which demonstrates the high diversity of the enzyme. Despite this ample divergence between enzyme groups, our 3D structure modeling showed both conservation and differences in amino acid residues participating in enzyme-substrate binding, which indicates the possibility that some enzymes are functionally specialized for the specific degradation of a substrate depending on the genetics of each species in the genus and the condition of the habitat where they evolved. The identification of alpha-glucuronidase isoenzymes would allow future use of genetic engineering and biocatalysis technologies aimed at specific production of the enzyme for its use in biotransformation.

Complete Bioconversion of Protopanaxadiol-Type Ginsenosides to Compound K by Extracellular Enzymes from the Isolated Strain Aspergillus tubingensis

A compound K-producing fungus was isolated from meju (fermented soybean brick) and identified as the generally recognized as safe (GRAS) strain Aspergillus tubingensis. The extracellular enzymes obtained after the cultivation of 6 days in the medium with 20 g/L citrus pectin as an inducer showed the highest compound K-producing activity among the inducers tested. Under the optimized conditions of 0.05 mM MgSO₄, 55 °C, pH 4.0, 13.4 mM protopanaxadiol (PPD)-type ginsenosides, and 11 mg/mL enzymes, the extracellular enzymes from A. tubingensis completely converted PPD-type ginsenosides in the ginseng extract to 13.4 mM (8.35 mg/mL) compound K after 20 h, with the highest concentration and productivity among the results reported so far. As far as we know, this is the first GRAS enzyme to completely convert all PPD-type ginsenosides to compound K.