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Background The complete degradation of the cellulose requires the synergistic action of endo-β- glucanase, exo-β-glucanase, and β-glucosidase. But endo-β-glucanase and exo-β-glucanase can be recovered by solid-liquid separation in cellulose hydrolysis by their cellulose binding domain (CBD), however, the β-glucosidases cannot be recovered because of most β- glucosidases without the CBD, so additional β-glucosidases are necessary for the next cellulose degradation. This will increase the cost of cellulose degradation. Results The glucose-tolerant β-glucosidase (BGL) from Thermoanaerobacterium thermosaccharolyticum DSM 571 was fused with cellulose binding domain (CBD) of Clostridium cellulovorans cellulosome anchoring protein by a peptide linker. The fusion enzyme (BGL-CBD) gene was overexpressed in Escherichia coli with the maximum β- glucosidase activity of 17 U/mL. Recombinant BGL-CBD was purified by heat treatment and following by Ni-NTA affinity. The enzymatic characteristics of the BGL-CBD showed optimal activities at pH 6.0 and 65°C. The fusion of CBD structure enhanced the hydrolytic efficiency of the BGL-CBD against cellobiose, which displayed a 6-fold increase in Vmax/Km in comparison with the BGL. A gram of cellulose was found to absorb 643 U of the fusion enzyme (BGL-CBD) in pH 6.0 at 50°C for 25 min with a high immobilization efficiency of 90%. Using the BGL-CBD as the catalyst, the yield of glucose reached a maximum of 90% from 100 g/L cellobiose and the BGL-CBD could retain over 85% activity after five batches with the yield of glucose all above 70%. The performance of the BGL-CBD on microcrystalline cellulose was also studied. The yield of the glucose was increased from 47% to 58% by adding the BGL-CBD to the cellulase, instead of adding the Novozyme 188. Conclusions The hydrolytic activity of BGL-CBD is greater than that of the Novozyme 188 in cellulose degradation. The article provides a prospect to decrease significantly the operational cost of the hydrolysis process. [ABSTRACT FROM AUTHOR]

In this work, recombinant Pichia pastoris GS115-lccA was cultured and expressed with the highest laccase activity of 2357 U/L with ABTS (2, 2'-nazinobis-(3-ethylbenzthiazoline-6-sulphonate)) as reacting substrate. To achieve the higher laccase activity, multiple key factors were screened (using a Plackett-Burman design of experiments methodology) related to the fermentation conditions for producing GS115-lccA. Subsequently, a Box-Behnken response surface methodology was employed for further optimization. The optimum fermentation conditions of the fermentation were obtained as follows: 0.603% methanol added into the culture every 24 h, medium optimal initial pH 7.1, and liquid medium volume of 20.4% provided the highest enzyme activity of 5235 U/L. The decolorization experiments of dyes (Reactive Blue KN-R and Acid Red 35) were carried with the laccase cultured by recombinant P. pastoris GS115-lccA. This purified enzyme showed excellent decolorization capacity. After 24 h, the decolorization of Reactive Blue KN-R with 100 mg/L at 50 °C, pH 4.5 using 20 mM acetate buffer with 2 U/mL purified enzyme was 91.33%, and for Acid Red 35, the decolorization was 78.96%. All results suggested that this laccase may be suitable for the wastewater treatment of similar azo and anthraquinone dyes from the deinking and dyeing industries. [ABSTRACT FROM AUTHOR]

To further improve the expression level of recombinant xylanase in Pichia pastoris, the xynB gene, encoding the mature peptide from Aspergillus niger NL-1, was designed and synthesized based on the synonymous condon bias of P. pastoris and optimized G+C content. 155 nucleotides were changed, and the GC content decreased from 57.7% to 43.6%. The synthetic xynB was inserted into the pPICZaA and then integrated into P. pastoris GS115. The activity of the recombinant xylanase reached 1414.7 U/mL, induced with 0.8% methanol after 14day cultivation at a temperature of 28°C in shake flasks, which was 267% higher than that of the native gene. Furthermore, the maximum xylanase activity of 20424.2 U/mL was obtained by high-density fermentation in a 5-L fermenter, which was the highest xylanase expression in P. pastoris yet reported. The recombinant xylanase had its optimal activity at a pH of 5.0 and temperature of 50°C. The recombinant xylanase was stable over a pH range of 4.5 to 8.0. Thus, this report provides an industrial means to produce the recombinant xylanase in P. pastoris. [ABSTRACT FROM AUTHOR]

Background: Thermally stable α-L-rhamnosidase with cleaving terminal α-L-rhamnose activity has great potential in industrial application. Therefore, it is necessary to find a proper method to improve the thermal stability of α-L-rhamnosidase. Results: In this study, addition of sorbitol has been found to increase the thermostability of α-L-rhamnosidase from Aspergillus terreus at temperatures ranging from 65 °C to 80 °C. Half-life and activation free energy with addition of 2.0 M sorbitol at 70 °C were increased by 17.2-fold, 8.2 kJ/mol, respectively. The analyses of the results of fluorescence spectroscopy and CD have indicated that sorbitol helped to protect the tertiary and secondary structure of α-L-rhamnosidase. Moreover, the isoquercitrin yield increased from 60.01 to 96.43% with the addition of 1.5 M of sorbitol at 70 °C. Conclusion: Our findings provide an effective approach for enhancing the thermostability of α-L-rhamnosidase from Aspergillus terreus, which makes it a good candidate for industrial processes of isoquercitrin preparation. [ABSTRACT FROM AUTHOR]

This study reports the combination of Ginkgo flavonoid (GF) and Coriolus versicolor polysaccharide (CVP) in the prevention and treatment of a mouse model of Alzheimer's disease (AD). GF is a traditional health product, and CVP is the main active ingredient of the medicinal fungus Coriolus versicolor. The Morris water maze test, the Y maze, and the step-through test showed that the combinational use of CVP and GF synergistically improved memory in a mouse model of AD. Based on H&E staining analysis, the combination of CVP and GF decreased the severity of the pathological findings in the brain. Given that the expression of IL-1β, IL-6, and TNF-α was downregulated, the inflammation response in AD mice was considered to be inhibited. The downregulation of GFAP further demonstrated that inflammation was reduced in the brain of AD mice following treatment. Moreover, the expression levels of superoxide dismutase (SOD) and catalase (CAT) were elevated in the brains of treated mice, indicating that oxidation levels were reduced upon the combination treatment. Our results provide new insights into the efficient utilization of traditional medicine for preventing dementia. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effect of Candida utilis and Aspergillus niger, combined with fermented Ginkgo biloba leaves (FGB) on immunity, antioxidant capability, lipid metabolism, and disease resistance against Aeromonas hydrophila infection in juvenile blunt snout bream (Megalobrama amblycephala). Fish were fed basal diets supplemented with fermented Ginkgo biloba leaves FGB1(0.125%), FGB2(0.25%), FGB3(0.5%), FGB4(1.0%), or Control (0.00%) respectively. At the end of the 60-day feeding trial, fish were challenged by A. hydrophila and mortality rate was recorded for the next 7 days. Results showed that, compared with the control, serum myeloperoxidase (MPO) activity of groups FGB1 and FGB2, alkaline phosphatase (AKP) and lysozyme (LZM) activity of group FGB2 increased significantly (P<0.05), while malondialdehyde (MDA) and low density lipoprotein cholesterol (LDL-C) contents of group FGB2, immunoglobulin M (IgM) activity of group FGB4 decreased significantly (P<0.05). Furthermore, Acid phosphatase (ACP), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH) and triglyceride (TG) activities were not affected (P>0.05). After A. hydrophila challenge, the relative mortality of group FGB1 and FGB2 were significantly lower than the control (P<0.05), however the highest rate was in group FGB4. Results of this study indicate that dietary supplementation of 0.125%~0.25% fermented G. biloba leaves can significantly enhance immunity, antioxidant capability, and lipid metabolism of blunt snout bream, as well as improve its disease resistance. [ABSTRACT FROM AUTHOR]