Laccase and Manganese Peroxidase Activities of Phellinus Robustus and Ganoderma Adspersum Grown on Food Industry Wastes in Submerged Fermentation

Phellinus robustus produced both laccase (700–4,000 U l⁻¹) and manganese peroxidase (MnP) (1,000–11,300 U l⁻¹) in fermentation of nine food wastes, whereas Ganoderma adspersum produced only laccase (600–34,000 U l⁻¹). Glucose provided high laccase and MnP activity of P. robustus but repressed enzyme production by G. adspersum. Ammonium sulphate and ammonium tartrate increased the P. robustus laccase yield (3-fold), whereas the accumulation of MnP was not enhanced by additional nitrogen.     

Acid phosphatase production by recombinant <Emphasis Type="Italic">Arxula adeninivorans</Emphasis>

Acid phosphatase production by recombinant Arxula adeninivorans was carried out in submerged fermentation. Using the Plackett–Burman design, three fermentation variables (pH, sucrose concentration, and peptone concentration) were identified to significantly affect acid phosphatase and biomass production, and these were optimized using response surface methodology of central composite design. The highest enzyme yields were attained in the medium with 3.9% sucrose and 1.6% peptone at pH 3.8. Because of optimization, 3.86- and 4.19-fold enhancement in enzyme production was achieved in shake flasks (17,054 U g⁻¹ DYB) and laboratory fermenter (18,465 U g⁻¹ DYB), respectively.     

Studies on the interaction between benzophenone and bovine serum albumin by spectroscopic methods

The interaction between benzophenone (BP) and bovine serum albumin (BSA) was investigated by the methods of fluorescence spectroscopy combined with UV–Vis absorption and circular dichroism (CD) measurements under simulative physiological conditions. The experiment results showed that the fluorescence quenching of BSA by BP was resulted from the formation of a BP–BSA complex and the corresponding association constants (K _a) between BP and BSA at four different temperatures had been determined using the modified Stern–Volmer equation. The enthalpy change (ΔH) and entropy change (ΔS) were calculated to be –43.73 kJ mol⁻¹ and −53.05 J mol⁻¹ K⁻¹, respectively, which suggested that hydrogen bond and van der Waals force played major roles in stabilizing the BP–BSA complex. Site marker competitive experiments indicated that the binding of BP to BSA primarily took place in site I (sub-domain IIA). The conformational investigation showed that the presence of BP decreased the α-helical content of BSA and induced the slight unfolding of the polypeptides of protein, which confirmed some micro-environmental and conformational changes of BSA molecules.     

Production of raw-starch-hydrolysing α-amylase from the newly isolated Geobacillus thermodenitrificans HRO10

An extracellular raw-starch-digesting α-amylase was isolated from Geobacillus thermodenitrificans HRO10. The culture conditions for the production of α-amylase by G. thermodenitrificans HRO10 was optimized in 1.2–l bioreactor using full 2⁴ and 3² factorial designs. From the optimal reaction conditions, a model (Y = − 594.206 − 0.178T² − 8.448pH² + 6.020TpH − 0.005T²pH²) was predicted, which was then used for α-amylase production. In the bioreactor studies, the enzyme yield under optimized conditions (pH 7.1, 49°C) was 30.20 U/ml, a 51% improvement over the results (19.97 U/ml) obtained when the traditional one-factor-at-a-time method was employed. This α-amylase does not require extraneous calcium ions for activity, which may be a commercially important observation.     

Strain improvement of <Emphasis Type="Italic">Trichoderma reesei</Emphasis> Rut C-30 for increased cellulase production

The strain of Trichoderma reesei Rut C-30 was subjected to mutation after treatment with N-methyl-N′-nitro-N-nitrosoguanidine (NG) for 6 h followed by UV irradiation for 15 min. Successive mutants showed enhanced cellulase production, clear hydrolysis zone and rapid growth on Avicel-containing plate. Particularly, the mutant NU-6 showed approximately two-fold increases in activity of both FPA and CMCase in shake flask culture when grown on basal medium containing peptone (1%) and wheat bran (1%). The enzyme production was further optimized using eight different media. When a mixture of lactose and yeast cream was used as cellulase inducer, the mutant NU-6 yielded the highest enzyme and cell production with a FPase activity of 6.2 U ml⁻¹, a CMCase activity of 54.2 U ml⁻¹, a β-glucosidase activity of 0.39 U ml⁻¹, and a fungal biomass of 12.6 mg ml⁻¹. It deserved noting that the mutant NU-6 also secreted large amounts of xylanases (291.3 U ml⁻¹). These results suggested that NU-6 should be an attractive producer for both cellulose and xylanase production.     

Nitrate reductase activity of two leafy vegetables as affected by nickel and different nitrogen forms

The author studied the effect of different nickel concentrations (0, 0.4, 40 and 80 μM Ni) on the nitrate reductase (NR) activity of New Zealand spinach (Tetragonia expansa Murr.) and lettuce (Lactuca sativa L. cv. Justyna) plants supplied with different nitrogen forms (NO₃ ⁻–N, NH₄ ⁺–N, NH₄NO₃). A low concentration of Ni (0.4 μM) did not cause statistically significant changes of the nitrate reductase activity in lettuce plants supplied with nitrate nitrogen (NO₃ ⁻–N) or mixed (NH₄NO₃) nitrogen form, but in New Zealand spinach leaves the enzyme activity decreased and increased, respectively. The introduction of 0.4 μM Ni in the medium containing ammonium ions as a sole source of nitrogen resulted in significantly increased NR activity in lettuce roots, and did not cause statistically significant changes of the enzyme activity in New Zealand spinach plants. At a high nickel level (Ni 40 or 80 μM), a significant decrease in the NR activity was observed in New Zealand spinach plants treated with nitrate or mixed nitrogen form, but it was much more marked in leaves than in roots. An exception was lack of significant changes of the enzyme activity in spinach leaves when plants were treated with 40 μM Ni and supplied with mixed nitrogen form, which resulted in the stronger reduction of the enzyme activity in roots than in leaves. The statistically significant drop in the NR activity was recorded in the aboveground parts of nickel-stressed lettuce plants supplied with NO₃ ⁻–N or NH₄NO₃. At the same time, there were no statistically significant changes recorded in lettuce roots, except for the drop of the enzyme activity in the roots of NO₃ ⁻-fed plants grown in the nutrient solution containing 80 μM Ni. An addition of high nickel doses to the nutrient solution contained ammonium nitrogen (NH₄ ⁺–N) did not affect the NR activity in New Zealand spinach plants and caused a high increase of this enzyme in lettuce organs, especially in roots. It should be stressed that, independently of nickel dose in New Zealand spinach plants supplied with ammonium form, NR activity in roots was dramatically higher than that in leaves. Moreover, in New Zealand spinach plants treated with NH₄ ⁺–N the enzyme activity in roots was even higher than in those supplied with NO₃ ⁻–N.     

Decolorization of 1:2 metal complex dye Acid blue 193 by a newly isolated fungus, Cladosporium cladosporioides

Summary A fungus Cladosporium cladosporioides isolated from coal sample as a decolorizing microorganism. It decolorized five different azo and triphenylmethane dyes like acid blue 193, acid black 210, crystal violet, reactive black B(S) and reactive black BL/LPR both on solid and in liquid broth medium. Culture broth of this fungus decolorized completely 100 mg of acid blue 193 l⁻¹ in 8 days. The extracellular enzyme of Cladosporium cladosporioides decolorized acid blue 193 on repeated addition to a total (out of 700 mg l⁻¹) concentration of 564 mg l⁻¹ within 168 h without significant decline in the activity, showing the resistant property of Cladosporium cladosporioides to a high concentration of the dye. The optimal temperature 40 °C, pH 5.6 and sugar concentration of 4% required for decolorization of acid blue 193. Cladosporium cladosporioides showed manganese peroxidase activity with 41 U l⁻¹, laccase activity with 1413 U l⁻¹ and lignin peroxidase activity was negligible after day 8 of incubation.     

Production of lipase by high cell density fed-batch culture of Candida cylindracea

Candida cylindracea NRRL Y-17506 was grown to produce extracellular lipase from oleic acid as a carbon source. Through flask cultures, it was found that the optimum initial oleic acid concentration for cell growth was 20 g l⁻¹. However, high initial concentrations of oleic acid up to 50 g l⁻¹ were not inhibitory. The highest extracellular lipase activity obtained in flask culture was 3.0 U ml⁻¹ after 48 h with 5 g l⁻¹ of initial oleic acid concentration. Fed-batch cultures (intermittent and stepwise feeding) were carried out to improve cell concentration and lipase activity. For the intermittent feeding fed-batch culture, the final cell concentration was 52 g l⁻¹ and the extracellular lipase activity was 6.3 U ml⁻¹ at 138.5 h. Stepwise feeding fed-batch cultures were carried out to simulate an exponential feeding and to investigate the effects of specific growth rate (0.02, 0.04 and 0.08 h⁻¹) on cell growth and lipase production. The highest final cell concentration obtained was 90 g l⁻¹ when the set point of specific growth rate (μ_set) was 0.02 h⁻¹. High specific growth rate (0.04 and 0.08 h⁻¹) decreased extracellular lipase production in the later part of fed-batch cultures due to build-up of the oleic acid oversupplied. The highest extracellular lipase activity was 23.7 U ml⁻¹ when μ_set was 0.02 h⁻¹, while the highest lipase productivity was 0.31 U ml⁻¹ h⁻¹ at μ_set of 0.08 h⁻¹.     

Production of fructose from inulin using mixed inulinases from <Emphasis Type="Italic">Aspergillus niger</Emphasis> and <Emphasis Type="Italic">Candida guilliermondii</Emphasis>

Two new effective microbial producers of inulinases were isolated from Jerusalem artichoke tubers grown in Thailand and identified as Aspergillus niger TISTR 3570 and Candida guilliermondii TISTR 5844. The inulinases produced by both these microorganisms were appropriate for hydrolysing inulin to fructose as the principal product. An initial inulin concentration of ∼100 g l⁻¹ and the enzyme concentration of 0.2 U g⁻¹ of substrate, yielded 37.5 g l⁻¹ of fructose in 20 h at 40°C when A. niger TISTR 3570 inulinase was the biocatalyst. The yield of fructose on inulin was 0.39 g g⁻¹. Under identical conditions, the yeast inulinase afforded 35.3 g l⁻¹ of fructose in 25 h. The fructose yield was 0.35 g g⁻¹ of substrate. The fructose productivities were 1.9 g l⁻¹ h⁻¹ and 1.4 g l⁻¹ h⁻¹ for the mold and yeast enzymes, respectively. After 20 h of reaction, the mold enzyme hydrolysate contained 53% fructose and more than 41% of initial inulin had been hydrolysed. Using the yeast enzymes, the hydrolysate contained nearly 38% fructose at 25 h and nearly 36% of initial inulin had been hydrolysed. The A. niger TISTR 3570 inulinases exhibited both endo-inulinase and exo-inulinase activities. In contrast, the yeast inulinases displayed mainly exo-inulinase activity. The mold and yeast crude inulinases mixed in the activity ratio of 5:1 proved superior to individual crude inulinases in hydrolysing inulin to fructose. The enzyme mixture provided a better combination of endo- and exo-inulinase activities than did the crude extracts of either the mold or the yeast individually.     

Production of plants resistant to <Emphasis Type="Italic">Alternaria carthami</Emphasis> via organogenesis and somatic embryogenesis of safflower cv. NARI-6 treated with fungal culture filtrates

The present study describes a system for efficient plant regeneration via organogenesis and somatic embryogenesis of safflower (Carthamus tinctorius L.) cv. NARI-6 in fungal culture filtrates (FCF)-treated cultures. FCF was prepared by culturing Alternaria carthami fungal mycelia in selection medium for host-specific toxin production. Cotyledon explants cultured on callus induction medium with different levels of FCF (10–50%) produced embryogenic callus. In organogenesis, 42.2% microshoots formed directly from embryogenic callus tissues in plant regeneration medium with 40% FCF. Isolated embryogenic callus cultured on embryo induction medium containing 40% FCF induced 50.2% somatic embryogenesis. Embryo germination percentage was decreased from 64.5 to 28 in embryo maturation medium containing 40% FCF. However, nine plantlets from organogenesis and 24 plantlets from somatic embryogenesis were selected as FCF-tolerant. Alternaria carthami fungal spores (5 × 10⁵ spores/ml) sprayed on the leaves of FCF-tolerant plants showed enhanced survival rate over control plants, which plants were more susceptible to fungal attack. The number of leaf spot lesions per leaf was decreased from 3.4 to 0.9 and their lesion length was also reduced from 2.9 to 0.7 mm in organogenic derived FCF-tolerant plants over control. In somatic embryo derived FCF-tolerant plants, the number of lesions was decreased from 3.1 to 0.4 and the lesion size was also reduced to 2.7–0.5 mm when compared to the control. This study also examined antioxidant enzyme activity in FCF-tolerant plants. Catalase (CAT) activity was slightly decreased whereas peroxidase (POD) activity was increased to a maximum of 42% (0.19 μmol min⁻¹ mg⁻¹ protein) from organogenesis and 47% (0.23 μmol min⁻¹ mg⁻¹ protein) from embryogenesis in FCF-tolerant plants. Superoxide dismutase (SOD) activity was also increased to 17% (149 U mg⁻¹ protein) and 19.5% (145 U mg⁻¹ protein) in FCF-tolerant plants derived from organogenesis and somatic embryogenesis when compared with control plants.     

Stability of lipase immobilized on <Emphasis Type="Italic">O</Emphasis>-pentynyl dextran

O-Pentynyl dextran (PyD), an amphiphilic polysaccharide derivative with a degree of substitution (DS) of 0.43 was compared with ion exchange resins Lewatit VP OC 1600, Amberlite XAD 761 and Duolite A568 for immobilization of Lipase from Rhizopus arrhizus by adsorption method. The immobilized enzymes were employed for esterification of octanoic acid with geraniol in n-hexane as model reaction. PyD showed higher lipase adsorption and with 249 μmol min⁻¹ g⁻¹ significant higher esterification activity than the other supports (67–83 μmol min⁻¹ g⁻¹). Biocatalysts from all types of supports except PyD became completely inactive within 8 weeks storing at −10 °C while lipase immobilized on PyD retained its full esterification activity for at least 14 weeks. In repeated use, yield decreased rapidly after two cycles for all supports except for PyD. For this biopolymeric support, constantly 90% yield was achieved even after eight cycles, when the biocatalyst was washed with n-hexane and water and then freeze-dried. To achieve this yield, prolonged reaction times were required, partly on the account of an increasing delay period, probably to adapt active conformation, until the reaction starts.     

Influence of agitation and aeration on growth and antibiotic production by <Emphasis Type="Italic">Xenorhabdus nematophila</Emphasis>

The effect of agitation and aeration on the growth and antibiotic production by Xenorhabdus nematophila YL001 grown in batch cultures were investigated. Efficiency of aeration and agitation was evaluated through the oxygen mass transfer coefficient (K _L a). With increase in K _L a, the biomass and antibiotic activity increased. Activity units of antibiotic and dry cell weight were increased to 232 U ml⁻¹ and 19.58 g l⁻¹, respectively, productivity in cell and antibiotic was up more than 30% when K _L a increased from 115.9 h⁻¹ to 185.7 h⁻¹. During the exponential growth phase, DO concentration was zero, the oxygen supply was not sufficient. So, based on process analysis, a three-stage oxygen supply control strategy was used to improved the DO concentration above 30% by controlling the agitation speed and aeration rate. The dry cell weight and activity units of antibiotic were further increased to 24.22 g l⁻¹ and 249 U ml⁻¹, and were improved by 24.0% and 7.0%, compared with fermentation at a constant agitation speed and a constant aeration rate (300 rev min⁻¹, 2.5 l min⁻¹).     

Production of inulinase by solid-state fermentation: effect of process parameters on production and preliminary characterization of enzyme preparations

This work was aimed at producing inulinase by solid-state fermentation of sugarcane bagasse, using factorial design to identify the effect of corn steep liquor (CSL) and soybean bran concentration, particle size of bagasse and size of inoculum. Maximum inulinase activity achieved was 250 U per g of dry substrate (gds) at 20% (w/w) of CSL, 5% (w/w) of soybean bran, 1 × 10¹⁰ cells mL⁻¹ and particle size of bagasse in the range 9/32 mesh. The use of soybean bran decreased the time to reach maximum activity from 96 to 24 h and the maximum productivity achieved was 8.87 U gds⁻¹ h⁻¹. The maximum activity was obtained at pH 5.0 and 55.0°C. Within the investigated range, the enzyme extract was more thermostable at 50.0°C, showing a D-value of 123.1 h and deactivation energy of 343.9 kJ gmol⁻¹. The extract showed highest stability from pH 4.5 to 4.8. Apparent K _m and V _max are 7.1 mM and 17.79 M min⁻¹, respectively.     

Activity of salicylic acid on the growth and biochemism of Chlorella vulgaris Beijerinck

This study was conducted to investigate the influence of salicylic acid (SA) on the growth and changes of nucleic acids, protein, photosynthetic pigments, sugar content and photosynthesis levels in the green alga Chlorella vulgaris Beijerinck (Chlorophyceae). The most significant changes in the content of nucleic acids and proteins was observed at the concentration 10⁻⁴ M SA between 8 and 12 day of cultivation. This concentration of SA increased the number of cells (about 40 %) and content of proteins (about 60 %) and its secretion to the medium. The slight stimulation of protein secretion occurred on the 12th day of cultivation at concentration 10⁻⁴ M, while in the range of 10⁻⁵ M to 10⁻⁶ M the protein secretion was inhibited. SA also stimulated the content of nucleic acids, especially RNA by 20–60 %, compared with the control. The most stimulating influence upon the contents of chlorophylls a and b (50–70 %), total carotenoids (25–57 %), sugar (27–41 %) and intensity of net photosynthesis (18–33 %) was found at 10⁻⁴ M of SA. At the concentration of 10⁻⁶ M SA the slight inhibition of growth and biochemical activity of the algae was recorded at the first days of cultivation.     

Enhancement of superoxide dismutase activity in the leaves of white clover (Trifolium repens L.) in response to polyethylene glycol-induced water stress

Effects of polyethylene glycol (PEG)-induced water stress on the activities of total leaf superoxide dismutase (SOD) and chloroplast SOD (including thylakoid-bound SOD and stroma SOD) are described in white clover (Trifolium repens L.) grown in solution culture from rooted cuttings. Both leaf SOD and chloroplast SOD activities were markedly enhanced with increasing concentration of PEG stress, generating osmotic potentials around the roots 0, −0.5, −1.0, −1.5 MPa. The effects increased with time up to 72 h. Chloroplast Fe-containing SOD represented about 30% of the total leaf SOD activity in the control plants and a significant increase in chloroplast SOD activity was found during the stress period. This accounted for about 35.5–71.1% of the total leaf SOD activity. The proportion of chloroplast SOD in total leaf SOD not only increased with the decreasing of osmotic potential, but also increased with incubation time. Furthermore, the increase in thylakoid-bound SOD activity was much higher than that of stroma SOD in chloroplast of plants under water stress. The enhanced chloroplastic SOD activity, especially thylakoid-bound SOD activity, demonstrated in Trifolium repens suggests that Fe-SOD located in chloroplasts play a more important role than cytosolic Cu/Zn-containing SODs in scavenging O₂ ⁻.     

Reduction of Cr(VI) by a Bacillus sp.

A Bacillus sp. RE was resistant to chromium and reduced Cr(VI) without accumulating chromium inside the cell. When Cr(VI) was 10 and 40 μg ml⁻¹, >95% of the total Cr(VI) was reduced in 24 and 72 h of growth, respectively, whereas at 80 μg Cr(VI) ml⁻¹ only 50% of Cr(VI) was reduced. However growth was not affected; the cell mass was 0.7–0.8 mg ml⁻¹ in all cases. The cell-free extract showed Cr(VI) reducing enzyme activity which was enhanced (>5 fold) by NADH and NADPH. Like whole cells the enzyme also reduced Cr(VI) with decreasing efficiency on increasing Cr(VI) concentration. The enzyme activity was optimal at pH 6.0 and 30 °C. The enzyme was stable up to 30 °C and from pH 5.5 to 8, but from pH 4 to 5 the enzyme was severely destabilized. Its K_m and V_max were 14 μm and 3.8 nmol min⁻¹ mg⁻¹ respectively. The enzyme activity was enhanced by Cu²⁺ and Ni²⁺ and inhibited by Hg²⁺. Received 21 September 2005; Revisions requested 5 October 2005; Revisions received 16 November 2005; Accepted 16 November 2005     

Optimization of Phosphatidylinositol-specific Phospholipase C Production Using Response Surface Methodology

Summary Response surface methodology was employed in optimizing the nutrient levels needed towards the optimal production of phosphatidylinositol-specific phospholipase C enzyme by Bacillus thuringiensis serovar. kurstaki. A 2³ factorial central composite experimental design was used. The multiple regression equation, relating the enzyme activity to the nutrient medium, was used to find the optimum values of glucose, peptone and dipotassium hydrogen phosphate. The optimum values of these variables for maximal enzyme production were found to be: glucose, 6.5 g l⁻¹; peptone, 5.38 g l⁻¹ and dipotassium hydrogen phosphate, 6.36 g l⁻¹ with the predicted enzyme activity of 0.96 U ml⁻¹.     

Codon optimization of <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> β-1,3-1,4-glucanase gene and its expression in <Emphasis Type="Italic">Pichia pastoris</Emphasis>

β-1,3-1,4-glucanase (EC3.2.1.73) as an important industrial enzyme has been widely used in the brewing and animal feed additive industry. To improve expression efficiency of recombinant β-1,3-1,4-glucanase from Bacillus licheniformis EGW039(CGMCC 0635) in methylotrophic yeast Pichia pastoris GS115, the DNA sequence encoding β-1,3-1,4-glucanase was designed and synthesized based on the codon bias of P. pastoris, the codons encoding 96 amino acids were optimized, in which a total of 102 nucleotides were changed, the G+C ratio was simultaneously increased from 43.6 to 45.5%. At shaking flask level, β-1,3-1,4-glucanase activity is 67.9 and 52.3 U ml⁻¹ with barley β-glucan and lichenan as substrate, respectively. At laboratory fermentor level, the secreted protein concentration is approximately 250 mg l⁻¹. The β-1,3-1,4-glucanase activity is 333.7 and 256.7 U ml⁻¹ with barley β-glucan and lichenan as substrate, respectively; however, no activity of this enzyme on cellulose is observed. Compared to the nonoptimized control, expression level of the optimized β-1,3-1,4-glucanase based on preferred codons in P. pastoris shown a 10-fold higher level. The codon-optimized enzyme was approximately 53.8% of the total secreted protein. The optimal acidity and temperature of this recombinant enzyme were pH 6.0 and 45°C, respectively.     

Effect of calcium on immobilization of rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) peroxidase for bioassays in sodium alginate and Agarose gel

The direct immobilization of soluble peroxidase isolated and partially purified from shoots of rice seedlings in calcium alginate beads and in calcium agarose gel was carried out. Peroxidase was assayed for guaiacol oxidation products in presence of hydrogen peroxide. The maximum specific activity and immobilization yield of the calcium agarose immobilized peroxidase reached 2,200 U mg⁻¹ protein (540 mU cm⁻³ gel) and 82%, respectively. In calcium alginate the maximum activity of peroxidase upon immobilization was 210 mU g⁻¹ bead with 46% yield. The optimal pH for agarose immobilized peroxidase was 7.0 which differed from the pH 6.0 for soluble peroxidase. The optimum temperature for the agarose immobilized peroxidase however was 30°C, which was similar to that of soluble peroxidase. The thermal stability of calcium agarose immobilized peroxidase significantly enhanced over a temperature range of 30∼60°C upon immobilization. The operational stability of peroxidase was examined with repeated hydrogen peroxide oxidation at varying time intervals. Based on 50% conversion of hydrogen peroxide and four times reuse of immobilized gel, the specific degradation of guaiacol for the agarose immobilized peroxidase increased three folds compared to that of soluble peroxidase. Nearly 165% increase in the enzyme protein binding to agarose in presence of calcium was noted. The results suggest that the presence of calcium, ions help in the immobilization process of peroxidase from rice shoots and mediates the direct binding of the enzyme to the agarose gel and that agarose seems to be a better immobilization matrix for peroxidase compared to sodium alginate.     

Covalent immobilization of β-1,4-glucosidase from <Emphasis Type="Italic">Agaricus arvensis</Emphasis> onto functionalized silicon oxide nanoparticles

An efficient β-1,4-glucosidase (BGL) secreting strain, Agaricus arvensis, was isolated and identified. The relative molecular weight of the purified A. arvensis BGL was 98 kDa, as determined by sodium dodecylsulfate polyacrylamide gel electrophoresis, or 780 kDa by size exclusion chromatography, indicating that the enzyme is an octamer. Using a crude enzyme preparation, A. arvensis BGL was covalently immobilized onto functionalized silicon oxide nanoparticles with an immobilization efficiency of 158%. The apparent V _max (k _cat) values of free and immobilized BGL under standard assay conditions were 3,028 U mg protein⁻¹ (4,945 s⁻¹) and 3,347 U mg protein⁻¹ (5,466 s⁻¹), respectively. The immobilized BGL showed a higher optimum temperature and improved thermostability as compared to the free enzyme. The half-life at 65 °C showed a 288-fold improvement over the free BGL. After 25 cycles, the immobilized enzyme still retained 95% of the original activity, thus demonstrating its prospects for commercial applications. High specific activity, high immobilization efficiency, improved stability, and reusability of A. arvensis BGL make this enzyme of potential interest in a number of industrial applications.