Activity

Bio-catalysis by enzymes on solid surfaces has been implemented in several practical applications. However, the current methods for efficient enzyme immobilization with retained activity need further development. Herein, a simple, rapid, and economical, bio-affinity-based approach was developed for the direct immobilization with high activity recovery of recombinant Bacillus subtilis catalase (CAT) from the crude lysates. Silaffin-3-derived pentalysine cluster (Sil3K) and its mutant variant (penta-arginine peptide; Sil3R) were used for the first time in the non-covalent immobilization of the recombinant enzyme on silica particles. The fusions Sil3K/Sil3R-tagged CAT were selectively loaded from the cell lysates onto the silica surface. Unexpectedly, the Lys-based tag (Sil3K) was the superior to Arg-based tag (Sil3R) or tag-less system for the high recovery of CAT activity upon immobilization; an 8.4-fold and 1.5-fold increase in activity recovery was observed for CAT-Sil3K compared with the tag-less CAT and CAT-Sil3R, respectively. Furthermore, the CAT-Sil3K immobilized on silica particles exhibited improved thermal, pH and storage stabilities, and retained 72% of the initial activity after five reaction cycles. selleckchem Moreover, CAT-Sil3K was released with approximately 85% recovery and 91% purity, in a biologically active form when free lysine solution was used as the eluent. Our data proved that Sil3K-tag, 12-mer peptide, can be a highly promising silica-affinity tag for effective enzyme immobilization with preserved activity. Additionally, the novel findings obtained here may open a new route not only for cost-effective enzyme immobilization approaches but also for high recovery of enzyme activity. V.The soybean soluble polysaccharides was prepared by mixed fermentation of lactic acid bacteria and Neurospora crassa and microwave treatment, and the functional properties and structure characteristics of soybean soluble polysaccharides before and after modification was compared. Results revealed that after fermentation treatment, the content of soybean soluble polysaccharides increased to 7.09%, which was 3.16 times that of raw materials, and the microwave treatment was further increased to 7.69%. The Glucose Adsorption Capacity, Glucose Dialysis Retardation Index and the α-Amylase Activity Inhibition Ration of soybean soluble polysaccharides increased significantly, promotes intestinal flora growth in vitro after fermentation of mixed bacteria and microwave treatment. At the same time, the analysis of monosaccharide composition and structural characteristics showed that the monosaccharide components of soybean soluble polysaccharides were redistributed after modification treatment, Scanning electron microscopy showed that modified soybean soluble polysaccharides has a larger surface area; Fourier Transform Infrared spectroscopy and X-ray Diffraction proved that the modification has slight changes in the functional groups and crystal structure of soybean soluble polysaccharides. These results suggested that okara may be a potentially inexpensive source of natural soybean soluble polysaccharides and a potential functional food ingredient. V.An exopolysaccharide (EPS)-producing strain SN-8 isolated from Dajiang was identified as Leuconostoc mesenteroides. When sucrose was used as the carbon source for fermentation, the output of EPS was 2.42 g/L. High performance liquid chromatography analysis confirmed the presence of monomers such as glucan and mannose. The molecular weight detection value is 2.0 × 105 Da. Fourier transform infrared spectroscopy displayed the EPS had the basic skeleton and functional groups of a typical polysaccharide structure. Scanning electron microscopy showed smooth surfaces and compact structure. Thermal performance analysis showed that the highest heat resistance temperature of the EPS was 80 °C. Compared with vitamin C, its hydroxyl radical scavenging rate was as high as 32% and 1,1-diphenyl-2-picrylhydrazyl scavenging rate was as high as 40% under the same concentration. The peanut oil was the most emulsifiable at a concentration of 1.5 mg/mL, and the emulsification index was 0.55. These results might show that the EPS had high application value. V.The fruiting body of Hericium erinaceus has been used to treat digestive system disorder-related diseases for over 2000 years in China. A novel polysaccharide, HEFP-2b, was obtained from H. erinaceus fruiting bodies. Physical and chemical analysis showed that HEFP-2b consisted of fucose, galactose, glucose, and mannose in molar ratio of 11.8122.8244.2821.09, and that its molecular weight was 3.252 × 104 Da. The backbone of HEFP-2b consisted of →6)-linked-α-D-Glcp-(1→ and →4)-β-D-Galp-(1→ and →3,6) -α-D-Manp linkage, with two side-branching units of (1→ and →6)-β-D-Galp and (1→ and →4)-α-D-Manp, terminated by Glc and Fuc. The results of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle arrest experiments revealed that HEFP-2b considerably inhibited the growth of colon cancer cells (HCT-116) in vitro. The growth inhibitory effects of HEFP-2b correlated with their ability to arrest the cell cycle at the S-phase. Our results will provide valuable information for future studies on HEFP-2b as a novel health-promoting functional food ingredient that can be used for treating colon cancer. V.A new approach of algal-polymer -sheets was performed by the embedding of two algal seaweeds (Ulva fasciata and Sargassum dentifolium) into cellulose acetate (CA) polymer forming two types of cellulose acetate; Ulva (CA-U) and Sargassum (CA-S) sheets. Afterward, the two sheets were characterized then subjected to 3-Rs evaluation (Removal, Recovery, and Reuse) of methylene blue dye (MB). Characterization data exhibited good properties for biosorption process. Algal biosorbents achieved more than twice biosorption capacity (Qmax) after the embedding into the polymer sheet. Additionally, according to factorial design data, the contact time and the dose of biosorbents had positive effects on the biosorption in the two sheets. Freundlich, Langmuir, and pseudo-second order models displayed good represented data in the two sheets. Furthermore, the two sheets (CA-U, followed by CA-S sheet) were successfully given more than 98% adsorption of 273 mg/l MB concentration. Moreover, the recovery and reuse data proved that the two sheets can be performed in good behavior for more than three cycles.