Expression of β-glucosidase An-bgl3 from Aspergillus niger for conversion of scopolin / 生物工程学报

Scopoletin is a coumarin compound with various biological activities including detumescence and analgesic, insecticidal, antibacterial and acaricidal effects. However, interference with scopolin and other components often leads to difficulties in purification of scopoletin with low extraction rates from plant resource. In this paper, heterologous expression of the gene encoding β-glucosidase An-bgl3 derived from Aspergillus niger were carried out. The expression product was purified and characterized with further structure-activity relationship between it and β-glucosidase analyzed. Subsequently, its ability for transforming scopolin from plant extract was studied. The results showed that the specific activity of the purified β-glucosidase An-bgl3 was 15.22 IU/mg, the apparent molecular weight was about 120 kDa. The optimum reaction temperature and pH were 55 ℃ and 4.0, respectively. Moreover, 10 mmol/L metal ions Fe2+ and Mn2+ increased the enzyme activity by 1.74-fold and 1.20-fold, respectively. A 10 mmol/L solution containing Tween-20, Tween-80 and Triton X-100 all inhibited the enzyme activity by 30%. The enzyme showed affinity towards scopolin and tolerated 10% methanol and 10% ethanol solution, respectively. The enzyme specifically hydrolyzed scopolin into scopoletin from the extract of Erycibe obtusifolia Benth with a 47.8% increase of scopoletin. This demonstrated that the β-glucosidase An-bgl3 from A. niger shows specificity on scopolin with good activities, thus providing an alternative method for increasing the extraction efficiency of scopoletin from plant material.

Expression and characterization of a bifunctional thermal β-glucosidase IuBgl3 from thermophilic archaeon Infirmifilum uzonense / 生物工程学报

β-glucosidase has important applications in food, medicine, biomass conversion and other fields. Therefore, exploring β-glucosidase with strong stability and excellent properties is a research hotspot. In this study, a GH3 family β-glucosidase gene named Iubgl3 was successfully cloned from Infirmifilum uzonense. Sequence analysis showed that the full length of Iubgl3 was 2 106 bp, encoding 702 amino acids, with a theoretical molecular weight of 77.0 kDa. The gene was cloned and expressed in E. coli and the enzymatic properties of purified IuBgl3 were studied. The results showed that the optimal pH and temperature for pNPG hydrolysis were 5.0 and 85 ℃, respectively. The enzyme has good thermal stability, and more than 85% of enzyme activity can be retained after being treated at 80 ℃ for2 h. This enzyme has good pH stability and more than 85% of its activity can be retained after being treated at pH 4.0-11.0 for 1 h. It was found that the enzyme had high hydrolysis ability to p-nitrophenyl β-d-glucoside (pNPG) and p-nitrophenyl β-d-xylopyranoside (pNPX). When pNPG was used as the substrate, the kinetic parameters Km and Vmax were 0.38 mmol and 248.55 μmol/(mg·min), respectively, and the catalytic efficiency kcat/Km was 6 149.20 s-1mmol-1. Most metal ions had no significant effect on the enzyme activity of IuBgl3. SDS completely inactivated the enzyme, while EDTA increased the enzyme activity by 30%. This study expanded the β-glucosidase gene diversity of the thermophilic archaea GH3 family and obtained a thermostable acid bifunctional enzyme with good industrial application potential.

Heterologous expression of a novel β-glucosidase BglD2 and its application in polydatin-hydrolyzing / 生物工程学报

A novel β-glucosidase BglD2 with glucose and ethanol tolerant properties was screened and cloned from the deep-sea bacterium Bacillus sp. D1. The application potential of BglD2 toward polydatin-hydrolyzing was also evaluated. BglD2 exhibited the maximal β-glucosidase activity at 45 °C and pH 6.5. BglD2 maintained approximately 50% of its origin activity after incubation at 30 °C and pH 6.5 for 20 h. BglD2 could hydrolyze a variety of substrates containing β (1→3), β (1→4), and β (1→6) bonds. The activity of β-glucosidase was enhanced to 2.0 fold and 2.3 fold by 100 mmol/L glucose and 150 mmol/L xylose, respectively. BglD2 possessed ethanol-stimulated and -tolerant properties. At 30 °C, the activity of BglD2 enhanced to 1.2 fold in the presence of 10% ethanol and even remained 60% in 25% ethanol. BglD2 could hydrolyze polydatin to produce resveratrol. At 35 °C, BglD2 hydrolyzed 86% polydatin after incubation for 2 h. Thus, BglD2 possessed glucose and ethanol tolerant properties and can be used as the potential candidate of catalyst for the production of resveratrol from polydatin.

Fungal Diversity and Enzyme Activity Associated with the Macroalgae, Agarum clathratum

Agarum clathratum, a brown macroalgae species, has recently become a serious environmental problem on the coasts of Korea. In an effort to solve this problem, fungal diversity associated with decaying A. clathratum was investigated and related β-glucosidase and endoglucanase activities were described. A total of 233 fungal strains were isolated from A. clathratum at 15 sites and identified 89 species based on morphology and a multigene analysis using the internal transcribed spacer region (ITS) and protein-coding genes including actin (act), β-tubulin (benA), calmodulin (CaM), and translation elongation factor (tef1). Acremonium, Corollospora, and Penicillium were the dominant genera, and Acremonium fuci and Corollospora gracilis were the dominant species. Fifty-one species exhibited cellulase activity, with A. fuci, Alfaria terrestris, Hypoxylon perforatum, P. madriti, and Pleosporales sp. Five showing the highest enzyme activities. Further enzyme quantification confirmed that these species had higher cellulase activity than P. crysogenum, a fungal species described in previous studies. This study lays the groundwork for bioremediation using fungi to remove decaying seaweed from populated areas and provides important background for potential industrial applications of environmentally friendly processes.

A simplified and miniaturized glucometer-based assay for the detection of β-glucosidase activity / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

β-Glucosidase activity assays constitute an important indicator for the early diagnosis of neonatal necrotizing enterocolitis and qualitative changes in medicinal plants. The drawbacks of the existing methods are high consumption of both time and reagents, complexity in operation, and requirement of expensive instruments and highly trained personnel. The present study provides a simplified, highly selective, and miniaturized glucometer-based strategy for the detection of β-glucosidase activity. Single-factor experiments showed that optimum β-glucosidase activity was exhibited at 50 °C and pH 5.0 in a citric acid-sodium citrate buffer when reacting with 0.03 g/mL salicin for 30 min. The procedure for detection was simplified without the need of a chromogenic reaction. Validation of the analytical method demonstrated that the accuracy, precision, repeatability, stability, and durability were good. The linear ranges of β-glucosidase in a buffer solution and rat serum were 0.0873–1.5498 U/mL and 0.4076–2.9019 U/mL, respectively. The proposed method was free from interference from β-dextranase, snailase, β-galactosidase, hemicellulase, and glucuronic acid released by baicalin. This demonstrated that the proposed assay had a higher selectivity than the conventional dinitrosalicylic acid (DNS) assay because of the specificity for salicin and unique recognition of glucose by a personal glucose meter. Miniaturization of the method resulted in a microassay for β-glucosidase activity. The easy-to-operate method was successfully used to detect a series of β-glucosidases extracted from bitter almonds and cultured by Aspergillus niger. In addition, the simplified and miniaturized glucometer-based assay has potential application in the point-of-care testing of β-glucosidase in many fields, including medical diagnostics, food safety, and environmental monitoring.

Measurement of Cellulolytic Potential of Cellulase Producing Bacteria

The bioconversion of cellulose and hemicellulose to soluble sugars is important for global stabilization and for a sustainable human society. Here, hundreds of cellulolytic bacteria were found in soil, compost and animal waste slurry of our environment. Bacillus spp. are aerobic cellulolytic bacteria. Here, two Bacillus strains 2414, 2579 (T) and their mixed culture utilized for measuring the cellulolytic potential. The capability of cellulolytic potential was analyzed by enriching the basal salt media with Whatman no.1 filter paper as a substrate for cellulose degradation. Here, Cellulose-degrading potential of Bacillus strains was measured by measuring the diameter of a clear zone around the colony and its hydrolytic value on cellulose Congo-Red agar media. The extracellular cellulase activities ranged from 0.08233 to 0.44 IU/mL for FPase and 0.243 to 0.595 IU/mL for endoglucanase assay. The maximum activities range of β-glucosidase or cellobiase activity was 0.6 to1.5 1U/ml. The maximum xylanase activities value Bacillus cellulolysticus 2579 (T), Bacillus subtilis 2414 and their mixed culture were 12.0,11.5 and 12.5 unit/mL, respectively. All the enzymes were stable at an optimum pH range value of 3.0-7.0 and temperature range of 30˚C-50˚C. The maximum filter paper degradation percentage was estimated to be 71.76% by mixed culture after 48hrs of incubation period, it was observed that the maximum filter paper degradation was done by mixed culture than Bacillus strains. Biodiesel production was estimated by following the EN-14103 method and ester content was calculated on the basis of response factor with a minimum set value of ester content will be 96.5%.

Chinese Medicine Amygdalin and β-Glucosidase Combined with Antibody Enzymatic Prodrug System As A Feasible Antitumor Therapy / 中国结合医学杂志

Amarogentin is an efficacious Chinese herbal medicine and a component of the bitter apricot kernel. It is commonly used as an expectorant and supplementary anti-cancer drug. β-Glucosidase is an enzyme that hydrolyzes the glycosidic bond between aryl and saccharide groups to release glucose. Upon their interaction, β-glucosidase catalyzes amarogentin to produce considerable amounts of hydrocyanic acid, which inhibits cytochrome C oxidase, the terminal enzyme in the mitochondrial respiration chain, and suspends adenosine triphosphate synthesis, resulting in cell death. Hydrocyanic acid is a cell-cycle-stage-nonspecific agent that kills cancer cells. Thus, β-glucosidase can be coupled with a tumor-specific monoclonal antibody. β-Glucosidase can combine with cancer-cell-surface antigens and specifically convert amarogentin to an active drug that acts on cancer cells and the surrounding antibodies to achieve a killing effect. β-Glucosidase is injected intravenously and recognizes cancer-cell-surface antigens with the help of an antibody. The prodrug amarogentin is infused after β-glucosidase has reached the target position. Coupling of cell membrane peptides with β-glucosidase allows the enzyme to penetrate capillary endothelial cells and clear extracellular deep solid tumors to kill the cells therein. The Chinese medicine amarogentin and β-glucosidase will become an important treatment for various tumors when an appropriate monoclonal antibody is developed.

Co-expression of β-glucosidase and Vitreoscilla hemoglobin in Escherichia coli / 生物工程学报

In producing recombinant β-glucosidase in Escherichia coli by high-cell density cultivation (HCDC), insufficient soluble oxygen is always a problem. To address it, Vitreoscilla hemoglobin (VHb) was introduced into Escherichia coli by the bicistron and T₇ promoter expression systems, to improve soluble oxygen by bacterial cells and thereby to enhance the biomass and recombinant β-glucosidase production. In the case of bicistron expression system, cell density in shaking flask reached OD₆₀₀=(4.24±0.29), 35.03% higher than that of the control without VHb. Correspondingly, the maximum activity of β-glucosidase co-expressed with VHb was (9.78±0.55) U/mL, 25.38% higher than that of the control. In a 3-L fermentor, the maximum activity of β-glucosidase was 141.23 U/mL, 35.57% higher than that of the control. In contrast, the activity of β-glucosidase co-expressed with VHb under T₇ promoter was lower than that of the control, either in flask or in fermentor. Co-expressing β-glucosidase with VHb using the bicistron expression system may improve the tolerance of E. coli to insufficient soluble oxygen and thus promote the bacterial biomass and the enzyme yield.

Molecular modification of β-glucosidase from the midgut of Macrotermes barneyi / 生物工程学报

Cellulose hydrolysis to glucose requires a series of cellulase enzymes, of which β-glucosidases play a crucial role. β-glucosidase (MbmgBG1) derived from the midgut of Macrotermes barneyi has higher glucose tolerance (maintaining more than 60% enzyme activity at 1.5 mol/L glucose). However, low enzyme activity and poor thermal stability limit the applications of β-glucosidase in food industries. Point mutants (F167L, T176C, E347I, R354K, N393G and V425M) were obtained by site-directed mutagenesis of non-conserved amino acids near conserved amino acids. Among them, the specific activities against to substrate pNPG of two mutants (F167L and R354K) were about 2-fold and 4-fold higher than that of MbmgBG1. Kcat/Km values were also higher than that of the wild-type, reflecting stronger affinity to the substrate and higher catalytic ability of mutants than MbmgBG1. When the glucose concentration was 1.5 mol/L, the enzyme activity of MbmgBG1 was about 60% of the original activity. F167L and R354K kept 60% enzymatic activity when the glucose concentrations of was 2.0 mol/L and 3.0 mol/L, respectively. These results lay a foundation for further studies on the catalytic efficiency of β-glucosidase.

Investigate optimum conditions and determinate changes of β-glucosidase activity in Scrophularia root under different drying conditions / 中国中药杂志

To explore the optimum conditions of β-glucosidase activity in Scrophularia root by using pNPG method. The extraction conditions and reaction conditions (such as extraction liquid type, reaction system, reaction time, temperature, and substrate concentration) were screened by using monofactorial experiment and homogeneous design. Then the changes of β-glucosidase activity in Scrophularia root were detected at the drying temperature of 40-100 ℃. The results showed that citric acid phosphate buffer had better extraction effect, and the maximum absorbance produced by enzymatic reaction was present at 50 ℃ environment after reaction for 30 min. Homogeneous design experiment determined that the optimal conditions were as follows: optimal extraction liquid pH 7.0; enzymatic reaction system pH 6.0; substrate concentration 20 mmol•L⁻¹. The change of enzyme activity was affected by drying temperature and water loss rate. In the drying temperature of 60-100 ℃, the enzyme activity was reduced rapidly with the increase in water loss rate, while the activity was seen even with 0% of water at 40 and 50 ℃. This study has laid the theoretical foundation for research of hydrolysis mechanism of iridoid glycosides and optimum drying process.

Glycoside hydrolase production by Aspergillus terreus CM20 using mixture design approach for enhanced enzymatic saccharification of alkali pretreated paddy straw.

A successful lignocellulosic ethanol production process needs to address the technological impediments such as cost-competitiveness and sustainability of the process. Effective biomass utilization requires a repertoire of enzymes including various accessory enzymes. Developing an enzyme preparation with defined hydrolytic activities can circumvent the need for supplementing cellulases with accessory enzymes for enhanced hydrolysis. With this objective, mixture design approach was used in the present study to enhance glycoside hydrolase production of a fungal isolate, Aspergillus terreus CM20, by determining the proportion of different lignocellulosic components as enzyme inducers in the culture medium. A mixture of paddy straw and wheat straw (1.42:1.58) resulted in improved cellulolytic activities. The precipitated crude enzyme showed higher CMCase (365.03 18 IU g-1), FPase (161.48 IU g-1), avicelase (15.46 IU g-1), β-glucosidase (920.92 IU g-1) and xylanase (9627.79 IU g-1) activities. The potential of the crude enzyme for saccharification of alkali pretreated paddy straw was also tested. Under optimum conditions, saccharification released 25.0 g L-1 of fermentable sugars. This indicates the superiority of the crude enzyme produced with respect to its hydrolytic enzyme components.

Expression of musca domestica β-glucosidase in the organs besides digestive system of Ⅲ instar larvae / 局解手术学杂志

Objective To study whether the organs besides digestive system of musca domestica Ⅲ instar larvae have the capability of produceing musca β-glucosidase.Methods Tissues of malpighian tubules,trachea,epiploon and body wall of musca domestica Ⅲ instar lar-vae were dissected under anatomic microscope,and the expression of β-glucosidase gene in these dissected tissues were detected by reverse transcription PCR.And the tissue localization of β-glucosidase mRNA was further identified by in situ hybridization.Moreover,anti-cellulase was used to determinate the tissue distribution with immunohistochemical staining.The relative mRNA expression levels of musca domesticaβ-glucosidase gene in these organs were tested by real-time quantitative PCR.Results The reverse transcription PCR showed that the ampli-fication products of β-glucosidase gene were observed in tissues of malpighian tubules,trachea and body wall.β-glucosidase mRNA was shown in the epithelium cells of malpighian tubules,trachea and body wall by in situ hybridization,and it was almost the same in the results of im-munohistochemical staining.The real-time quantitative PCR showed that the relative expression quantity of β-glucosidase gene in malpighian tubules and body wall were higher than that in foregut,while it was lower in itrachea than that in foregut.And it was of statistical difference in gene expression level of β-glucosidase among these organs (P <0.05).Conclusion Malpighian tubules,trachea and body wall of musca domestica Ⅲ instar larvae have the function of secreting β-glucosidase.Combining with the characteristics of secreting β-glucosidase in most organs of digestive system,it may provide a new biological method for the prevention and treatment of human diseases transmitted by musca domestica with the use of taget gene β-glucosidase.

Multifunctional cellulolytic activities from Streptomyces osmaniensis for agricultural and enzyme industry

Aims: The aims of this study were to screen for cellulose degradation activity from actinomycetes using agar plate method, detect β-glucosidase activity, morphology and molecular taxonomy study. Methodology and results: Preliminary screening for cellulose degrading Actinomycete was done on the carboxymethyl cellulose agar (CMC agar) and detected by flooding with gram iodine. It was found that 190 isolates were cellulase producing actinomycetes. Actinomycete isolate CDF2L1D13 showed maximum clear zone around the colony and the highest hydrolysis capacity value was 3.93. β-glucosidase activity was examined by measuring the amount of paranitrophenol (pNP) librated by Tako method. Study on comparison of the enzyme activity in CMC broth with alternative broth was performed. The highest β-glucosidase activity was found on alternative production medium that supplemented rice bran as a carbon source. β-glucosidase activity was 0.401 U/mL. The optimum pH of alternative production medium for producing β-glucosidase was at pH value 7 and incubated at 30 °C. Isolate CDF2L1D13 was antagonistic actinomycete against rice blast pathogen (Pyricularia oryzae). The character of this isolate was showed white color of substrate mycelium, white color of aerial mycelium, gray spore and spiral spore chain. Actinomycete isolate CDF2L1D13 was phylogenetically similar to Streptomyces osmaniensis. Conclusion, significance and impact of study: The result from this study indicated that Streptomyces osmaniensis has the potential on β-glucosidase production and it is antagonistic actinomycete against Pyricularia oryzae.

Effect of D-cellobiose on oral bioavailability of gentiopicroside / 中国中药杂志

In this study, the effect of D-cellobiose on oral bioavailability of gentiopicroside (GPS) was investigate. The influence of D-cellobiose on GPS was achieved by calculating the residual GPS after being degraded with β-glucosidase or intestinal flora, and the data demonstrated D-cellobiose could inhibit the degradation of GPS in intestines; in bioavailability experiment, D-cellobiose could significantly improve the oral bioavailability (P<0.05) of GPS at the mass ratio of 1∶5, 1∶10 (GPS-D-cellobiose). D-cellobiose applied in this study may improve the oral bioavailability of GPS through delaying the degradation in intestines.

Clinical features and GBA gene mutation in two siblings with typeⅢ Gaucher disease / 临床儿科杂志

Objective To report clinical manifestations, electroencephalogram (EEG), and the genotypes of two siblings with type Ⅲ Gaucher disease.Methods Two patients with different features were siblings. Their clinical data, signs, peripheral leukocytes acid β-glucosidase activity, andGBA gene were analyzed.Results (1) The proband was a boy. He visited us at the age of nine years old because of hepatosplenomegaly, thrombocytopenia and growth retardation without any neurologic symp-toms. He had normal intelligence but abnormal EEG ifndings. The activity of acid β-glucosidase in his leucocytes decreased to 1.5 nmol h-1·mg-1 Pr (normal range 6.0-16.7 nmol h-1·mg-1 Pr), supporting the diagnosis of type Ⅲ Gaucher disease. (2) The elder sister of the proband was 12 years old. She had tonic-clonic seizure and myoclonus seizure from the age of seven years old. Mild hepatomegaly, abnormal EEG, poor effect for antiepileptics, and progressive deterioration of psychomotor abilities were found. Her blood leucocytes acid β-glucosidase activity decreased to 1.8 nmol h-1·mg-1 Pr (normal range 6.0-16.7 nmol h-1·mg-1 Pr). Two heterozygous missense mutations, c.680A>G, (p.N188S) and c.1342G>C (p.D409H) were detected from the two siblings, respec-tively.Conclusions Patients with type Ⅲ Gaucher disease usually have the onset in childhood with typical features of Gaucher disease without neurologic involvement. Abnormal EEG may be helpful to the differential diagnosis of type I or type Ⅲ. On the other hand, neurologic manifestations could be presented as the ifrst symptom in some patients without viscera enlargement. The patients of type Ⅲ Gaucher disease with the same genotype could have different phenotypes, even between the siblings.

Preparation and Identification of Cetuximab-β-Glucosidase Conjugates / 天津医药

Objective To prepare cetuximab-β-glucosidase conjugates and to identify its enzymatic activity and an?tibody activity. Methods Cetuximab andβ-glucosidase were crosslinked by Sulfosuccinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (Sulfo-SMCC). Cetuximab-β-glucosidase conjugates and its enzymatic and antibody activity were examined by non-reduced SDS-PAGE, colorimetry and indirect immunofluorescence assay. Results We can see clear bands ofβ-glucosidase, cetuximab, cetuximab-β-glucosidase conjugates through electropherogram. Although the en?zymatic activity of cetuximab-β-glucosidase conjugates was lower than that ofβ-glucosidase (U/L:672.97±46.19 vs 869.50± 57.28,t=5.972,P<0.05) shown by colorimetry assay, it still maintain good enzymatic activity. Under fluorescence micro?scope, we can see the conjugates interacted with human bladder cancer EJ cells are in a red fluorescence. Conclusion Ce?tuximab,β-glucosidase were crosslinked successfully by Sulfo-SMCC without altered its enzymatic and antibody activity.

Cellulase Production by Bacteria: A Review.

Cellulose is an abundant natural biopolymer on earth and most dominating Agricultural waste. This cellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. It can be degraded by cellulase produced by cellulolytic bacteria. This enzyme has various industrial applications and now considered as major group of industrial enzyme. The review discusses application of cellulase, classification of cellulase, quantification of cellulase, the types of cellulolytic bacteria and their screening. It describes the current knowledge of cellulase production by submerged fermentation and solid state fermentation, properties of cellulase and cloning and expression of cellulase gene. The biotechnological aspect of cellulase research and their future prospects are also discussed.