Immobilization of a pectinlyase from Aspergillus niger for application in food technology

A novel protease-immobilized carbon catalyst for the effective fragmentation of proteins in high-TDS wastewater generated in tanneries: Spectral and electrochemical studies

The aim of this study was to degrade proteins in high-total dissolved solids (TDS)-containing wastewater produced during the soaking process in tanneries (tannery-TDS wastewater) using a halotolerant protease-assisted nanoporous carbon catalyst (STPNPAC). A halotolerant protease was obtained from the halophile, Lysinibacillus macroides, using animal fleshing as the substrate. The protease was immobilized using ethylene diamine (EDA)/glutaraldehyde functionalized nanoporous activated carbon (EGNPAC). The optimum conditions for the immobilization of protease were determined as time (120 min), pH (6), protease concentration (575-600 U/g), EGNPAC size, salinity, and temperature (30 °C). The immobilization was confirmed by FTIR, TGA-DSC, SEM, and XRD analyses. The adsorption kinetics was consistent with a pseudo first order rate constant of 1.43 × 10^-2 min^-1. The thermodynamic parameters (ΔG, ΔH, and ΔS) confirmed the effective immobilization of the protease onto EGNPAC. STPNAPC was found to efficiently degrade the proteins in tannery-TDS wastewater, with a complete fragmentation time of 90 min at pH 6 and 30 °C. Accordingly, the protein fragmentation was confirmed by UV-visible and UV-fluorescence spectroscopy, ESI-mass spectrometric analysis and circular dichroic studies. The formation of protein hydrolysates was confirmed by cyclic voltammetry and electrical impedance studies. BOD₅: COD value, 0.426 of treated tannery-TDS wastewater may favor sequential biological treatment processes.

Fabrication, characterization and application of pectin degrading Fe3O4-SiO2 nanobiocatalyst

The covalent binding of pectinase onto amino functionalized silica-coated magnetic nanoparticles (CSMNPs) through glutaraldehyde activation was investigated for nanobiocatalyst fabrication. The average particle size and morphology of the nanoparticles were characterized using transmission electron microscopy (TEM). The statistical analysis for TEM image suggests that the coating and binding process did not cause any significant change in size of MNPs. The morphological and phase change of the magnetic nanoparticles (MNPs) after various coatings and immobilization were characterized by X-ray diffraction (XRD) studies. The various surface modifications and pectinase binding onto nanoparticles were confirmed by Fourier transform infrared (FT-IR) spectroscopy. The maximum activity of immobilized pectinase was obtained at its weight ratio of 19.0×10(-3) mg bound pectinase/mg CSMNPs. The pH, temperature, reusability, storage ability and kinetic studies were established to monitor their improved stability and activity of the fabricated nanobiocatalyst. Furthermore, the application was extended in the clarification of Malus domestica juice.

Biotechnological potential of pectinolytic complexes of fungi

Plant cell wall-degrading enzymes, such as cellulases, hemicellulases and pectinases, have been extensively studied because of their well documented biotechnological potential, mainly in the food industry. In particular, lytic enzymes from filamentous fungi have been the subject of a vast number of studies due both to their advantages as models for enzyme production and their characteristics. The demand for such enzymes is rapidly increasing, as are the efforts to improve their production and to implement their use in several industrial processes, with the goal of making them more efficient and environment-friendly. The present review focuses mainly on pectinolytic enzymes of filamentous fungi, which are responsible for degradation of pectin, one of the major components of the plant cell wall. Also discussed are the past and current strategies for the production of cell wall-degrading enzymes and their present applications in a number of biotechnological areas.

Separation and utilization of pectin lyase from commercial pectic enzyme via highly methoxylated cross-linked alcohol-insoluble solid chromatography for wine methanol reduction

The isolation and utilization of pectin lyase (PL) from commercial pectic enzyme for methanol reduction in wine production was investigated. PL can be separated from pectinesterase (PE) and polygalacturonase (PG) on HM-CL-AIS affinity chromatography at pH 4; however, it is difficult to further distinguish PE from PG. Some desirable physicochemical properties such as transmittance, lightness, redness, and lower total pectin content are found in the external enzyme adding groups (PL, PE and PG, and pectic enzyme groups) in comparison to the control group. Methanol contents in pectic enzyme and the PE and PG groups increase from 628 +/- 13 (control group) to 3103 +/- 16 and 1736 +/- 67 mg/L ethanol in the final products, respectively. Nevertheless, the adding of PL does not cause any increase in methanol content. The results present in this study suggest that the HM-CL-AIS column is a simple, inexpensive, convenient, and effective method for PL purification. Moreover, the partial purified PL is a potential replacement of commercial pectic enzyme for pectin depolymerizing, methanol content reducing, and wine quality improving in wine production.

Preparation and properties of an immobilized pectinlyase for the treatment of fruit juices

Pectinlyase, present in different commercial pectinases used in juice technology, was immobilized on alginate beads. The optimal conditions were: 0.17 g alginate ml(-1), 1.2% (w/v or v/v) enzyme concentration and acetic-HCl/glycine-HCl buffer at pH 3.6 or tris-HCl/imidazole buffer at pH 6.4. Maximum percentage of immobilization (10.6%) was obtained with Rapidase C80. Kinetic parameters of free and immobilized pectinlyase were also determined. The pH and temperature at which activity of soluble and immobilized enzyme was maximum were 7.2 and 55 degrees C. Thermal stability was not significantly altered by immobilization, especially at 40 degrees C, showing two periods of different stability. Free and immobilized preparation reduced the viscosity of highly esterified pectin from 1.09 to 0.70 and 0.72 mm(2) s(-1), respectively, after 30 min at 40 degrees C. Furthermore, the immobilized enzyme could be re-used through 4 cycles and the efficiency loss in viscosity reduction was found to be only 9.2%.

Sugar-cane juice induces pectin lyase and polygalacturonase in Penicillium griseoroseum

The use of other inducers as substitutes for pectin was studied aiming to reduce the production costs of pectic enzymes. The effects of sugar-cane juice on the production of pectin lyase (PL) and polygalacturonase (PG) by Penicillium griseoroseum were investigated. The fungus was cultured in a mineral medium (pH 6.3) in a rotary shaker (150 rpm) for 48 h at 25oC. Culture media were supplemented with yeast extract and sucrose or sugar-cane juice. Sugar-cane juice added singly to the medium promoted higher PL activity and mycelial dry weight when compared to pectin and the use of sugar-cane juice and yeast extract yielded levels of PG activity that were similar to those obtained with sucrose-yeast extract or pectin. The results indicated that, even at low concentrations, sugar-cane juice was capable of inducing pectin lyase and polygalacturonase with no cellulase activity in P. griseoroseum.