Check out our New Publishers' Select for Free Articles

Applied Biochemistry and Biotechnology: Part A: Enzyme Engineering and Biotechnology (v.133, #2)

Feruloyl esterase by Dominic W. S. Wong (pp. 87-112).

Feruloyl esterase forms a part of the enzyme complex that acts collectively and synergistically to completely hydrolyze xylan to its monomers. The enzyme has found potential uses in a wide variety of applications of interest to the agrifood and pharmaceutical industries. This review describes the enzymology of feruloyl esterases involved in xylan degradation. The occurrence of feruloyl esterases in various microorganisms and their physiochemical properties are presented. The nature of the enzyme substrates and products, the role of synergistic interactions with xylanases and other accessory enzymes, as well as the sequence-structure relating to the reaction mechanism are emphasized.

Keywords: Feruloyl esterase; ferulic acid and crosslinks; feruloylated oligosaccharide; hydroxycinnamic acid; glucurono arabinoxylan

Modeling and optimization of biopolymer (Polyhydroxyalkanoates) production from ice cream residue by novel statistical experimental design by Kwang-Min Lee; David F. Gilmore (pp. 113-148).

Polyhydroxyalkanoates (PHAs) are thermoplastic polyesters synthesized by Ralstonia eutropha and other bacteria as a form of intracellular carbon and energy storage and are accumulated as lipid inclusions in the cytoplasm of these bacteria. The modeling and optimization of PHA production by fermentation from industrial waste (ice cream residue) was studied by employing statistical experimental design methods. A series of iterative experimental designs was used to find optimal factor conditions (medium components and fermentation process time) in the order of fractional factorial design, path of steepest ascent, and full factorial augmented with axial design (rotational central composite design). An optimal range characterized by lipid (15 mg/mL) and % lipid (88%) values was found and further investigated to verify the optimal conditions for PHA production from ice cream (56.68 mL of ice cream or 56.68% ice cream in water [v/v], 5.03 mL of buffer, 1 mL of mineral salts solution, 100 μL of trace element solution, 100 mL of seed culture, and 213.76 h of fermentation time).

Keywords: Polyhydroxyalkanoate; optimization; design of experiment; modeling; repeated measures

Expression, refolding, and characterization of GFE peptide-fused human interferon-α2a in Escherichia coli by Zhen Yan; Li Lu; Jihong Shi; Chunjie Bao; Wei Han; Yongjie Wu; Yingqi Zhang (pp. 149-162).

Interferon-α2a (IFN-α2a) has been used for the treatment of various viral infections and cancers for many years. However some untolerable side effects have limited its application in some aspects. To evaluate whether or not an oligopeptide containing GFE motif can home human IFN-α2a to specific tissues, a fusion gene was constructed by fusing the coding sequence of GFE peptide (CGFECVRQCPERC), which was screened from phage display peptide library, to the 3′ end of human IFN-α2a gene by recombinant DNA technique. Fusion protein rhIFN-α2a-GFE was expressed in Escherichia coli as inclusion bodies using a T7 RNA polymerase expression system, pET-22b, refolded through dialysis and purified to homogeneity to >95% of purity by affinity chromatography. Characterization by sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting demonstrated the authenticity of the fusion protein. Purified rhIFN-α2a-GFE was found to be functionally active in terms of its antiviral activity for about 2.5×10⁸ IU/mg in vitro. Yields of the purified fusion protein were about 200 mg/L of culture medium. Tissue distribution assay in mouse showed that at 30 min IFN-α2a could be enriched sevenfold higher in lung in the targeted IFN group of mice than in the standard IFN group of mice, and last for a long time. At 1 h, IFN-α2a in the targeted IFN group was still 4.02-fold higher than that in the standard group. This confirmed that GFE peptide has the ability to selectively deliver its fusion partner IFN-α2a to lungs. The results also showed that the IFN-α2a-GFE could be specifically enriched in kidney and liver. Its distribution in kidney was concordant with the finding of GFE receptor, MDP, in kidney. However, the IFN-α2a-GFE in liver may imply some significance in pharmacology and toxicology.

Keywords: DNA recombination; expression; interferon-α2a; purification; target peptide; tissue distribution

Production of β-galactosidase by Trichoderma reesei FTKO-39 in wheat bran by P. R. Adalberto; A. C. Massabni; A. J. Goulart; J. Contiero; E. C. Carmona; L. Cardello; R. Monti (pp. 163-170).

Trichoderma reesei FTKO-39 grown at 35°C for 5 d on wheat bran supplemented with MgCl₂ and lactose as the carbon source produced two isozymes of β-galactosidase: BGT I and BGT II. These isozymes were partially purified on a DEAE-Trisacryl column. Both BGT I and BGT II fractions exhibited optimum activity at 65°C, but the pH optima were 4.0 and 6.5, respectively. The isozymes also showed similar thermal stability. However, BGT I was more stable than BGT II in a pH range of 3.0–10.0. At least two different β-galactosidases are produced by T. reesei, as revealed by the two bands seen on a 6% polyacrylamide gel stained for activity.

Keywords: β-Galactosidase; isozymes; partial purification; semisolid fermentation; Trichoderma reesei

Analysis of performance of an anaerobic sequencing batch reactor submitted to increasing organic load with different influent concentrations and cycle lengths by Fabiana Xavier Chebel; Suzana Maria Ratusznei; José Alberto Domingues Rodrigues; Marcelo Zaiat; Eugênio Foresti (pp. 171-187).

The performance of an anaerobic sequencing batch reactor (ASBR) was assessed when submitted to increasing organic load with different influent concentrations and cycle lengths. The 5-L mechanically stirred (75rpm) ASBR contained 2 L of granular biomass and treated 2 L of synthetic wastewater per cycle. Volumetric organic loads (VOLs) from 0.66 to 2.88 g of chemical oxygen demand (COD)/(L·d) were applied by using influent concentrations from 550 to 3600 mg of COD/L in 8- and 12-h cycles. Reactor stability was maintained for VOLs from 0.66 to 2.36 g of COD/(L·d), with organic matter removal efficiencies for filtered samples (ɛ F) between 84 and 88%. For VOLs from 0.78 to 2.36 g of COD/(L·d) at an influent concentration of 2000 mg of COD/L, when cycle length was reduced from 12 to 8 h, ɛ F did not vary, yet showed a very distinct behavior from the other conditions. In addition, two operation strategies were studied for VOLs with approximately similar values of 2.36 and 2.08 g of COD/(L·d). One involved operation with an influent concentration of 2000 mg of COD/L and an 8-h cycle, whereas the other involved an influent concentration of 2600 mg of COD/L and a 12-h cycle. Only the former resulted in system stability and efficiency. These results indicate that besides organic load, influent concentration and cycle length play a significant role in ASBR systems.

Keywords: Anaerobic sequencing batch reactor; organic load; influent concentration; cycle length

Sections

Personal tools

Applied Biochemistry and Biotechnology: Part A: Enzyme Engineering and Biotechnology (v.133, #2)

Sections

Personal tools

Local resources

Applied Biochemistry and Biotechnology: Part A: Enzyme Engineering and Biotechnology (v.133, #2)