|Formulation:||In 3.2 M ammonium sulphate (stabilised with BSA)|
|Stability:||> 4 years at 4oC|
|Synonyms:||beta-glucosidase; beta-D-glucoside glucohydrolase|
|Concentration:||Supplied at ~ 40 U/mL|
|Expression:||Purified from Aspergillus niger|
|Specificity:||Hydrolysis of terminal, non-reducing β-D-glucosyl residues with release of β-D-glucose.|
|Specific Activity:||~ 80 U/mg (40oC, pH 4.0 on p-nitrophenyl β-glucoside)|
|Unit Definition:||One Unit of β-Glucosidase activity is defined as the amount of enzyme required to release one µmole of p-nitrophenol from p-nitrophenyl β-glucoside per minute at 40oC and pH 4.0.|
|Application examples:||Applications established in diagnostics and research within the food and feed, carbohydrate and biofuels industries.|
High purity β-Glucosidase (Aspergillus niger) for use in research, biochemical enzyme assays and in vitro diagnostic analysis.
See our complete Carbohydrate Active enZYme products listing.
33-β-D-Glucosyl-cellotriose O-GM - 1,4-β-D-Glucosyl-D-Mannose O-GGM - 1,4-β-D-Cellobiosyl-D-Mannose O-GMM - 1,4-β-D-Glucosyl-D-Mannobiose O-LAM3 - Laminaritriose O-LAM4 - Laminaritetraose O-LAM5 - Laminaripentaose O-LAM6 - Laminarihexaose O-LAM7 - Laminariheptaose O-LAM8 - Laminarioctaose O-LAM9 - Laminarinonaose
(Trichoderma longibrachiatum) E-CELAN - Cellulase (endo-1,4-β-D-glucanase)
(Aspergillus niger) E-CELBA - Cellulase (endo-1,4-β-D-glucanase)
(Bacillus amyloliquefaciens) E-CELTE - Cellulase (endo-1,4-β-D-glucanase)
(Talaromyces emersonii) E-CELTH - Cellulase (endo-1,4-β-D-glucanase)
(Thermobifida halotolerans) E-CELTM - Cellulase (endo-1,4-β-D-glucanase)
(Thermotoga maritima) E-LICHN - Lichenase (endo-1,3:1,4-β-D-Glucanase)
(Bacillus subtilis) E-LAMSE - endo-1,3-β-D-Glucanase (Trichoderma sp.)
McCleary, B. V. & Codd, R. (1991). Journal of the Science of Food and Agriculture, 55(2), 303-312.
A commercially available enzymic method for the quantitative measurement of (1→3),(1→4)-β-glucan has been simplified to allow analysis of up to 10 grain samples in 70 min or of 100–200 samples by a single operator in a day. These improvements have been achieved with no loss in accuracy or precision and with an increase in reliability. The glucose oxidase/peroxidase reagent has been significantly improved to ensure colour stability for periods of up to 1 h after development. Some problems experienced with the original method have been addressed and resolved, and further experiments to demonstrate the quantitative nature of the assay have been designed and performed.Hide Abstract
McCleary, B. V. & Harrington, J. (1988). “Methods in Enzymology”, Volume 160, (H. Gilbert, Ed.), Elsevier Inc., pp. 575-583.
β-D-Glucosidases have been isolated and purified from a number of fungal culture filtrates. A number of β-glucosidases, including those from almond emulsin and from Aspergillus niger 15, do not have a strict requirement for a D-gluco configuration. The enzyme from almond emulsin catalyzes hydrolysis of both β-D-glucopyranosides and β-D-galactopyranosides and evidence has been obtained for the involvement of different enzyme active sites. An enzyme purified to homogeneity from culture filtrates of Aspergillus niger 15 has a very broad specificity with activity on β-D-glucosides, β-D-xylosides, β-D-galactosides, and β-L-arabinosides. β-glucosidase in combination with a specific endo-β-glucanase could find widespread application in the quantification of a range of β-D-glucans such as (1→4)-β-D-glucan, (1→3)-β-D-glucan, (1→3),(1→4)-β-D-glucan, and (1→3),1→6)-β-D-glucan. Together with endo-1,4-β-D-mannanase and β-D-mannosidase it may also prove useful in the measurement of β-D-glucomannans. A method for the assay of (1→3),(1→4)-β-D-glucan has already been developed using a highly purified β-D-glucosidase from a commercially available Aspergillus niger enzyme preparation. This chapter describes the purification of this enzyme and report on some of its properties.Hide Abstract
McCleary, B. V. & Nurthen, E. (1986). Journal of the Institute of Brewing, 92(2), 168-173.
A method developed for the quantification of (1→3)(1→4)-β-D-glucan in barley flour has been modified to allow its use in the measurement of this component in malt, wort, beer and spent grain. For malt samples, free D-glucose was first removed with aqueous ethanol. Quantification of the polymer in wort and beer samples involved precipitation of the β-glucan with ammonium sulphate followed by washing with aqueous ethanol to remove free D-glucose. Spent grain was lyophilised and milled and then analysed by the method developed for malt. In all cases, the β-glucan was depolymerised with lichenase and the resultant β-gluco-oligosaccharides hydrolysed to D-glucose with β-D-glucosidase. The released D-glucose was then specifically determined using glucose oxidase-peroxidase reagent.Hide Abstract
McCleary, B. V., Gibson, T. S., Allen, H. & Gams, T. C. (1986). Starch, 38(12), 433-437.
Mixed linkage β-glucane and pentosanes (mainly arabinoxylanes) are the major endosperm cell-wall polysaccharides of barley and wheat respectively. These polysaccharides, although minor components of the whole grain, significantly affect the industrial utilization of these cereals. The modification of barley corns during malting requires the dissolution of the β-glucan in the cell-wall of the starch endosperm. High β-glucane concentration in wort and beer effect the rate of filtration and can also lead to precipitate or gel formation in the final product. In a similar manner, pentosane is thought to cause filtration problems with wheat starch hydrolysates by increasing viscosity and by producing gelatinous precipitate which blocks filters. Ironically, it is this same viscosity building and water binding capacity which is considered to render pentosanes of considerable value in dough development and bread storage (anti-staling functions). In the current paper, some aspects of the beneficial and detrimental effects of pentosans and β-glucan in the industrial utilization of wheat and barley are discussed. More specifically, enzymic methods for the preparation, analysis and identification of these polysaccharides and for the removal of their functional properties, are described in detail.Hide Abstract
McCleary, B. V. & Glennie-Holmes, M. (1985). Journal of the Institute of Brewing, 91(5), 285-295.
A simple and quantitative method for the determination of (1→3) (1→4)-β-D-glucan in barley flour and malt is described. The method allows direct analysis of β-glucan in flour and malt slurries. Mixed-linkage β-glucan is specifically depolymerized with a highly purified (1→3) (1→4)-β-D-glucanase (lichenase), from Bacillus subtilis, to tri-, tetra- and higher degree of polymerization (d.p.) oligosaccharides. These oligosaccharides are then specifically and quantitatively hydrolysed to glucose using purified β-D-glucosidase. The glucose is then specifically determined using glucose oxidase/peroxidase reagent. Since barley flours contain only low levels of glucose, and maltosaccharides do not interfere with the assay, removal of low d.p. sugars is not necessary. Blank values are determined for each sample allowing the direct measurement of β-glucan in values are determined for each sample allowing the direct measurement of β-glucan in malt samples. α-Amylase does not interfere with the assay. The method is suitable for the routine analysis of β-glucan in barley samples derived from breeding programs; 50 samples can be analysed by a single operator in a day. Evaluation of the technique on different days has indicated a mean standard error of 0-1 for barley flour samples containing 3-8 and 4-6% (w/w) β-glucan content.Hide Abstract
A comparative biochemical investigation of the impeding effect of C1-oxidizing LPMOs on cellobiohydrolases.
Keller, M. B., Badino, S. F., Røjel, N., Sørensen, T. H., Kari, J., McBrayer, B., Borch, K., Blossom, B. M. & Westh, P. (2021). Journal of Biological Chemistry, 296.
Lytic polysaccharide monooxygenases (LPMOs) are known to act synergistically with glycoside hydrolases in industrial cellulolytic cocktails. However, a few studies have reported severe impeding effects of C1-oxidizing LPMOs on the activity of reducing-end cellobiohydrolases. The mechanism for this effect remains unknown, but it may have important implications as reducing-end cellobiohydrolases make up a significant part of such cocktails. To elucidate whether the impeding effect is general for different reducing-end cellobiohydrolases and study the underlying mechanism, we conducted a comparative biochemical investigation of the cooperation between a C1-oxidizing LPMO from Thielavia terrestris and three reducing-end cellobiohydrolases; Trichoderma reesei (TrCel7A), T. terrestris (TtCel7A), and Myceliophthora heterothallica (MhCel7A). The enzymes were heterologously expressed in the same organism and thoroughly characterized biochemically. The data showed distinct differences in synergistic effects between the LPMO and the cellobiohydrolases; TrCel7A was severely impeded, TtCel7A was moderately impeded, while MhCel7A was slightly boosted by the LPMO. We investigated effects of C1-oxidations on cellulose chains on the activity of the cellobiohydrolases and found reduced activity against oxidized cellulose in steady-state and pre-steady-state experiments. The oxidations led to reduced maximal velocity of the cellobiohydrolases and reduced rates of substrate complexation. The extent of these effects differed for the cellobiohydrolases and scaled with the extent of the impeding effect observed in the synergy experiments. Based on these results, we suggest that C1-oxidized chain ends are poor attack sites for reducing-end cellobiohydrolases. The severity of the impeding effects varied considerably among the cellobiohydrolases, which may be relevant to consider for optimization of industrial cocktails.Hide Abstract
The role of non-starch polysaccharides in determining the air-water interfacial properties of wheat, rye, and oat dough liquor constituents.
Janssen, F., Wouters, A. G., Meeus, Y., Moldenaers, P., Vermant, J. & Delcour, J. A. (2020). Food Hydrocolloids, 105, 105771.
Dough gas cell stability is a prerequisite for obtaining breads with high specific volume and homogeneous crumb. The contribution of cereal endogenous non-starch polysaccharides (NSPs) to gas cell stability during wheat, rye, and oat bread making is still unclear. In this work, the aqueous phases from their fermented doughs were isolated as dough liquor (DL) by ultracentrifugation. The foaming, bulk shear rheology, and air-water (A-W) interfacial properties of wheat and rye DLs (treated with and without endoxylanase) and oat DL (treated with and without both lichenase and β-d-glucosidase) were studied. Enzymatic hydrolysis drastically reduced the apparent bulk shear viscosity of the different DLs and resulted in increased and decreased moduli (or magnitude) of the complex A-W interfacial shear viscosities of wheat and rye DLs, respectively. The latter implies that (non-hydrolyzed) rye DL arabinoxylan strengthens the A-W interfacial film consisting of adsorbed proteins and lipids. No measurable A-W interfacial shear viscosities were obtained for oat DL irrespective of whether its β-D-glucans were hydrolyzed or not. This is probably because lipids dominate the oat DL A-W interfaces. The knowledge generated provides a fundamental basis for specifically modifying the composition of the aqueous phase in wheat, rye, and oat doughs to improve the quality of mixed cereal breads.Hide Abstract
Zhou, L., da Costa Sousa, L., Dale, B. E., Feng, J. X. & Balan, V. (2018). Royal Society Open Science, 5(6), 171529.
Removing alkali-soluble lignin using extractive ammonia (EA) pretreatment of corn stover (CS) is known to improve biomass conversion efficiency during enzymatic hydrolysis. In this study, we investigated the effect of alkali-soluble lignin on six purified core glycosyl hydrolases and their enzyme synergies, adopting 31 enzyme combinations derived by a five-component simplex centroid model, during EA-CS hydrolysis. Hydrolysis experiment was carried out using EA-CS(-) (approx. 40% lignin removed during EA pretreatment) and EA-CS(+) (where no lignin was extracted). Enzymatic hydrolysis experiments were done at three different enzyme mass loadings (7.5, 15 and 30 mg protein g-1 glucan), using a previously developed high-throughput microplate-based protocol, and the sugar yields of glucose and xylose were detected. The optimal enzyme combinations (based on % protein mass loading) of six core glycosyl hydrolases for EA-CS(-) and EA-CS(+) were determined that gave high sugar conversion. The inhibition of lignin on optimal enzyme ratios was studied, by adding fixed amount of alkali-soluble lignin fractions to EA-CS(-), and pure Avicel, beechwood xylan and evaluating their sugar conversion. The optimal enzyme ratios that gave higher sugar conversion for EA-CS(-) were CBH I: 27.2-28.2%, CBH II: 18.2-22.2%, EG I: 29.2-34.3%, EX: 9.0-14.1%, βX: 7.2-10.2%, βG: 1.0-5.0% (at 7.5-30 mg g-1 protein mass loading). Endoglucanase was inhibited to a greater extent than other core cellulases and xylanases by lignin during enzyme hydrolysis. We also found that alkali-soluble lignin inhibits cellulase more strongly than hemicellulase during the course of enzyme hydrolysis.Hide Abstract
Chylenski, P., Forsberg, Z., Ståhlberg, J., Várnai, A., Lersch, M., Bengtsson, O., Sæbø, S., Horn, S. J. & Eijsink, V. G. (2017). Journal of Biotechnology, 246, 16-23.
Despite recent progress, saccharification of lignocellulosic biomass is still a major cost driver in biorefining. In this study, we present the development of minimal enzyme cocktails for hydrolysis of Norway spruce and sugarcane bagasse, which were pretreated using the so-called BALI™ process, which is based on sulfite pulping technology. Minimal enzyme cocktails were composed using several glycoside hydrolases purified from the industrially relevant filamentous fungus Trichoderma reesei and a purified commercial β-glucosidase from Aspergillus niger. The contribution of in-house expressed lytic polysaccharide monooxygenases (LPMOs) was also tested, since oxidative cleavage of cellulose by such LPMOs is known to be beneficial for conversion efficiency. We show that the optimized cocktails permit efficient saccharification at reasonable enzyme loadings and that the effect of the LPMOs is substrate-dependent. Using a cocktail comprising only four enzymes, glucan conversion for Norway spruce reached >80% at enzyme loadings of 8 mg/g glucan, whereas almost 100% conversion was achieved at 16 mg/g.Hide Abstract
Microwave Assisted Chemical Pretreatment Method for Bio-ethanol Production from Rice Straw.
Singh, R., Srivastava, M., Rohatgi, B., Kar, A. & Shukla, A. (2017). Asian Journal of Chemistry, 29(5), 943.
Continuous depletion in fossil fuel reserves and their contribution towards greenhouse gas emissions compelled the scientist to explore renewable sources of energy. Abundance of rice straw and its poor utilization is one major research question addressed through the present research work. The microwave assisted chemical treatment for Indian rice straw for bio-ethanol production has not been investigated so far and present study has provided insight in to the area of research. In the present research work, feasibility of microwave assisted alkali, acid and peroxide pretreatment has been investigated for rice straw. Mainly three chemicals NaOH, H2SO4 and H2O2 have been used. It has been found that the combination of microwave pretreatment with H2O2, H2SO4 and NaOH enhances the saccharification of rice straw, respectively by removing lignin and hemicelluloses in large quantity. Maximum reducing sugar is found through H2O2-microwave pretreatment (1453.64µg/mL). SEM images also confirmed that the surface of the samples treated with microwave assisted H2O2 were more ruptured than H2SO4 and NaOH. It becomes quite evident from experimental analysis that the enzymatic saccharification of rice straw can be assisted with microwave-chemical pretreatment.Hide Abstract
Ogunmolu, F. E., Jagadeesha, N. B. K., Kumar, R., Kumar, P., Gupta, D. & Yazdani, S. S. (2017). Biotechnology for Biofuels, 10(71).
Background: GH7 cellobiohydrolases (CBH1) are vital for the breakdown of cellulose. We had previously observed the enzyme as the most dominant protein in the active cellulose-hydrolyzing secretome of the hypercellulolytic ascomycete—Penicillium funiculosum (NCIM1228). To understand its contributions to cellulosic biomass saccharification in comparison with GH7 cellobiohydrolase from the industrial workhorse—Trichoderma reesei, we natively purified and functionally characterized the only GH7 cellobiohydrolase identified and present in the genome of the fungus. Results: There were marginal differences observed in the stability of both enzymes, with P. funiculosum (PfCBH1) showing an optimal thermal midpoint (Tm) of 68°C at pH 4.4 as against an optimal Tm of 65°C at pH 4.7 for T. reesei (TrCBH1). Nevertheless, PfCBH1 had an approximate threefold lower binding affinity (Km), an 18-fold higher turnover rate (kcat), a sixfold higher catalytic efficiency as well as a 26-fold higher enzyme-inhibitor complex equilibrium dissociation constant (Ki) than TrCBH1 on p-nitrophenyl-β-D-lactopyranoside (pNPL). Although both enzymes hydrolyzed cellooligomers (G2–G6) and microcrystalline cellulose, releasing cellobiose and glucose as the major products, the propensity was more with PfCBH1. We equally observed this trend during the hydrolysis of pretreated wheat straws in tandem with other core cellulases under the same conditions. Molecular dynamic simulations conducted on a homology model built using the TrCBH1 structure (PDB ID: 8CEL) as a template enabled us to directly examine the effects of substrate and products on the protein dynamics. While the catalytic triads—EXDXXE motifs—were conserved between the two enzymes, subtle variations in regions enclosing the catalytic path were observed, and relations to functionality highlighted. Conclusion: To the best of our knowledge, this is the first report about a comprehensive and comparative description of CBH1 from hypercellulolytic ascomycete—P. funiculosum NCIM1228, against the backdrop of the same enzyme from the industrial workhorse—T. reesei. Our study reveals PfCBH1 as a viable alternative for CBH1 from T. reesei in industrial cellulase cocktails.Hide Abstract
Strobel, K. L., Pfeiffer, K. A., Blanch, H. W. & Clark, D. S. (2016). Biotechnology and Bioengineering, 133(6), 1369-1374.
Non-productive binding of cellulases to lignin inhibits enzymatic hydrolysis of biomass, increasing enzyme requirements and the cost of biofuels. This study used site-directed mutagenesis of the Trichoderma Cel7A carbohydrate binding module (CBM) and linker to investigate the mechanisms of adsorption to lignin and engineer a cellulase with increased binding specificity for cellulose. CBM mutations that added hydrophobic or positively charged residues decreased the specificity for cellulose, while mutations that added negatively charged residues increased the specificity. Linker mutations that altered predicted glycosylation patterns selectively impacted lignin affinity. Beneficial mutations were combined to generate a mutant with 2.5-fold less lignin affinity while fully retaining cellulose affinity. This mutant was uninhibited by added lignin during hydrolysis of Avicel and generated 40% more glucose than the wild-type enzyme from dilute acid-pretreated Miscanthus.Hide Abstract
Badhan, A., Wang, Y., Gruninger, R., Patton, D., Powlowski, J., Tsang, A. & McAllister, T. (2014). BMC Biotechnology, 14(1), 31.
Background: Efficient conversion of lignocellulosic biomass to fermentable sugars requires the synergistic action of multiple enzymes; consequently enzyme mixtures must be properly formulated for effective hydrolysis. The nature of an optimal enzyme blends depends on the type of pretreatment employed as well the characteristics of the substrate. In this study, statistical experimental design was used to develop mixtures of recombinant glycosyl hydrolases from thermophilic and anaerobic fungi that enhanced the digestion of alkaline peroxide treated alfalfa hay and barley straw by mixed rumen enzymes as well as commercial cellulases (Accelerase 1500, A1500; Accelerase XC, AXC). Results: Combinations of feruloyl and acetyl xylan esterases (FAE1a; AXE16A_ASPNG), endoglucanase GH7 (EGL7A_THITE) and polygalacturonase (PGA28A_ASPNG) with rumen enzymes improved straw digestion. Inclusion of pectinase (PGA28A_ASPNG), endoxylanase (XYN11A_THITE), feruloyl esterase (FAE1a) and β-glucosidase (E-BGLUC) with A1500 or endoglucanase GH7 (EGL7A_THITE) and β-xylosidase (E-BXSRB) with AXC increased glucose release from alfalfa hay. Glucose yield from straw was improved when FAE1a and endoglucanase GH7 (EGL7A_THITE) were added to A1500, while FAE1a and AXE16A_ASPNG enhanced the activity of AXC on straw. Xylose release from alfalfa hay was augmented by supplementing A1500 with E-BGLUC, or AXC with EGL7A_THITE and XYN11A_THITE. Adding arabinofuranosidase (ABF54B_ASPNG) and esterases (AXE16A_ASPNG; AXE16B_ASPNG) to A1500, or FAE1a and AXE16A_ASPNG to AXC enhanced xylose release from barley straw, a response confirmed in a scaled up assay. Conclusion: The efficacy of commercial enzyme mixtures as well as mixed enzymes from the rumen was improved through formulation with synergetic recombinant enzymes. This approach reliably identified supplemental enzymes that enhanced sugar release from alkaline pretreated alfalfa hay and barley straw.Hide Abstract
Amat, D., Arora, A., Nain, L. & Saxena, A. K. (2014). Annals of Microbiology, 64(1), 267-274.
Xanthomonas axonopodis pv. Punicae strain—a potent plant pathogen that causes blight disease in pomegranate—was screened for cellulolytic and xylanolytic enzyme production. This strain produced endo-β-1,4-glucanase, filter paper lyase activity (FPA), β-glucosidase and xylanase activities. Enzyme production was optimized with respect to major nutrient sources like carbon and nitrogen. Carboxy methyl cellulose (CMC) was a better inducer for FPA, CMCase and xylanase production, while starch was found to be best for cellobiase. Soybean meal/yeast extract at 0.5 % were better nitrogen sources for both cellulolytic and xylanolytic enzyme production while cellobiase and xylanase production was higher with peptone. Surfactants had no significant effect on levels of extracellular cellulases and xylanases. A temperature of 28°C and pH 6–8 were optimum for production of enzyme activities. Growth under optimized conditions resulted in increases in different enzyme activities of around 1.72- to 5-fold. Physico-chemical characterization of enzymes showed that they were active over broad range of pH 4–8 with an optimum at 8. Cellulolytic enzymes showed a temperature optimum at around 55°C while xylanase had highest activity at 45°C. Heat treatment of enzyme extract at 75°C for 1 h showed that xylanase activity was more stable than cellulolytic activities. Xanthomonas enzyme extracts were able to act on biologically pretreated paddy straw to release reducing sugars, and the amount of reducing sugars increased with incubation time. Thus, the enzymes produced by X. axonopodis pv. punicae are more versatile and resilient with respect to their activity at different pH and temperature. These enzymes can be overproduced and find application in different industries including food, pulp and paper and biorefineries for conversion of lignocellulosic biomass.Hide Abstract
Najah, M., Mayot, E., Mahendra-Wijaya, I. P., Griffiths, A. D., Ladame, S. & Drevelle, A. (2013). Analytical Chemistry, 85(20), 9807-9814.
Droplet-based microfluidics is a powerful technique allowing ultra-high-throughput screening of large libraries of enzymes or microorganisms for the selection of the most efficient variants. Most applications in droplet microfluidic screening systems use fluorogenic substrates to measure enzymatic activities with fluorescence readout. It is important, however, that there is little or no fluorophore exchange between droplets, a condition not met with most commonly employed substrates. Here we report the synthesis of fluorogenic substrates for glycosidases based on a sulfonated 7-hydroxycoumarin scaffold. We found that the presence of the sulfonate group effectively prevents leakage of the coumarin from droplets, no exchange of the sulfonated coumarins being detected over 24 h at 30°C. The fluorescence properties of these substrates were characterized over a wide pH range, and their specificity was studied on a panel of relevant glycosidases (cellulases and xylanases) in microtiter plates. Finally, the β-D-cellobioside-6,8-difluoro-7-hydroxycoumarin-4-methanesulfonate substrate was used to assay cellobiohydrolase activity on model bacterial strains (Escherichia coli and Bacillus subtilis) in a droplet-based microfluidic format. These new substrates can be used to assay glycosidase activities in a wide pH range (4–11) and with incubation times of up to 24 h in droplet-based microfluidic systems.Hide Abstract
Rieder, A., Grimmer, S., Aachmann, F. L., Westereng, B., Kolset, S. O. & Knutsen, S. H. (2013). Carbohydrate Polymers, 92(2), 2075-2083.
Even if carbohydrate preparations from plant/fungal sources have a high degree of purity, observed immune-stimulation may be caused by minute sample contaminations. Using the example of different β-glucans we present a range of analytical tools crucial for validation of possible immune-stimulatory effects. Two yeast (MacroGard and Zymosan) and one cereal β-glucan (CBG40) increased IL-8 secretion by HT-29 cells considerably. Degradation of the β-glucan samples with β-glucan specific enzymes did hardly influence the effect of Zymosan and CBG40 but significantly decreased the effect of MacroGard. Stimulation of IL-8 secretion by CBG40 and Zymosan was hence not due to their β-glucan content. Instead, the effect of the CBG40 sample was due to low levels of LPS despite the inability of the known LPS inhibitor Polymyxin B to supress its stimulatory effect. We conclude that targeted enzymatic degradation of samples is a powerful validation tool to investigate carbohydrate specific immune-modulation.Hide Abstract
Chang, C., Sustarich, J., Bharadwaj, R., Chandrasekaran, A., Adams, P. D. & Singh, A. K. (2013). Lab Chip, 13(9), 1817-1822.
Heterogeneous enzymatic reactions are used in many industrial processes including pulp and paper, food, and biofuel production. Industrially-relevant optimization of the enzymes used in these processes requires assaying them with insoluble substrates. However, platforms for high throughput heterogeneous assays do not exist thereby severely increasing the cost and time of enzyme optimization, or leading to the use of assays with soluble substrates for convenient, but non-ideal, optimization. We present an innovative approach to perform heterogeneous reactions in a high throughput fashion using droplet microfluidics. Droplets provide a facile platform for heterogeneous reactions as internal recirculation allows rapid mixing of insoluble substrates with soluble enzymes. Moreover, it is easy to generate hundreds or thousands of picoliter droplets in a small footprint chip allowing many parallel reactions. We validate our approach by screening combinations of cellulases with real-world insoluble substrates, and demonstrate that the chip-based screening is in excellent agreement with the conventional screening methods, while offering advantages of throughput, speed and lower reagent consumption. We believe that our approach, while demonstrated for a biofuel application, provides a generic platform for high throughput monitoring of heterogeneous reactions.Hide Abstract
Saritha, M., Arora, A. & Nain, L. (2012). Bioresource Technology, 104, 459-465.
Delignification of paddy straw with the white-rot fungus, Trametes hirsuta under solid state fermentation, for enhanced sugar recovery by enzymatic saccharification was studied. T. hirsuta MTCC136 showed high ligninase and low cellulase activities. Solid state fermentation of paddy straw with T. hirsuta enhanced carbohydrate content by 11.1% within 10 days of incubation. Alkali extracts of Trametes pretreated paddy straw showed high absorbance at 205 nm indicating high lignin break down. The amount of value-added lignin recovered from the Trametes pretreated paddy straw was much higher than controls. Enzymatic hydrolysis of the Trametes pretreated paddy straw yielded much higher sugars than controls and yields increased till 120 h of incubation. Saccharification efficiency of the biologically pretreated paddy straw with Accelerase® 1500 was 52.69% within 72 h and was higher than controls. Thus, the study brings out the delignification potential of T. hirsuta for pretreatment of lignocellulosic substrate and facilitating efficient enzymatic digestibility of cellulose.Hide Abstract
Bharadwaj, R., Wong, A., Knierim, B., Singh, S., Holmes, B. M., Auer, M., Simmons, B. A., Adams, P. D. & Singh, A. K. (2011). Bioresource Technology, 102(2), 1329-1337.
The high cost of lignocellulolytic enzymes is one of the main barriers towards the development of economically competitive biorefineries. Enzyme engineering can be used to significantly increase the production rate as well as specific activity of enzymes. However, the success of enzyme optimization efforts is currently limited by a lack of robust high-throughput (HTP) cellulase screening platforms for insoluble pretreated lignocellulosic substrates. We have developed a cost-effective microplate based HTP enzyme-screening platform for ionic liquid (IL) pretreated lignocellulose. By performing in-situ biomass regeneration in micro-volumes, we can volumetrically meter biomass (sub-mg loading) and also precisely control the amount of residual IL for engineering novel IL-tolerant cellulases. Our platform only requires straightforward liquid-handling steps and allows the integration of biomass regeneration, washing, saccharification, and imaging steps in a single microtiter plate. The proposed method can be used to screen individual cellulases as well as to develop novel cellulase cocktails.Hide Abstract
Pricelius, S., Murkovic, M., Souter, P. & Guebitz, G. M. (2009). Journal of Agricultural and Food Chemistry, 57(3), 1006-1012.
Attractive color is one of the most important sensory characteristics of fruit and berry products, and elderberry juice is widely used as natural colorant. When pectinase preparations were used in the production of elderberry juice for clarification, a concomitant decrease of anthocyanins and thus a color loss were observed. This paper demonstrates that this is due to side glycosidase activities contained in commercial pectinase preparations from Aspergillus sp. Using LC-MS, sequential deglycosylation of cyanidin-3-sambubioside, cy-3-glucoside, cy-3-sambubioside-5-glucoside, and cy-3,5-diglucoside was found to be catalyzed by specific glycosidases contained in the pectinase preparations. There was no big difference in the deglycosylation rate between monoglucosidic or diglucosidic anthocyanins. However, the degradation rate was decreased when rutinose was attached to cyanidin, whereas the structure of the aglycone itself had almost no influence. Pure β-glucosidases from Agrobacterium species and Aspergillus niger and the β-glucosidase N188 from A. niger did not show any conversion of anthocyanins, indicating the presence of specific glycosidases. Thus, an activity gel based assay was developed to detect anthocyanin-specific glycosidase activity in enzyme preparations, and according to LC-MS peptide mass mapping of digested bands, homologies to a β-glucosidase from Aspergillus kawachii were found.Hide Abstract