Candida antarctica Lipase B Immobilized onto Chitin Conjugated with POSS® Compounds: Useful Tool for Rapeseed Oil Conversion.

A new method is proposed for the production of a novel chitin-polyhedral oligomeric silsesquioxanes (POSS) enzyme support. Analysis by such techniques as X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed the effective functionalization of the chitin surface. The resulting hybrid carriers were used in the process of immobilization of the lipase type b from Candida antarctica (CALB). Fourier transform infrared spectroscopy (FTIR) confirmed the effective immobilization of the enzyme. The tests of the catalytic activity showed that the resulting support-biocatalyst systems remain hydrolytically active (retention of the hydrolytic activity up to 87% for the chitin + Methacryl POSS® cage mixture (MPOSS) + CALB after 24 h of the immobilization), as well as represents good thermal and operational stability, and retain over 80% of its activity in a wide range of temperatures (30-60 °C) and pH (6-9). Chitin-POSS-lipase systems were used in the transesterification processes of rapeseed oil at various reaction conditions. Produced systems allowed the total conversion of the oil to fatty acid methyl esters (FAME) and glycerol after 24 h of the process at pH 10 and a temperature 40 °C, while the Methacryl POSS® cage mixture (MPOSS) was used as a chitin-modifying agent.

Chitin-lignin material as a novel matrix for enzyme immobilization.

Innovative materials were made via the combination of chitin and lignin, and the immobilization of lipase from Aspergillus niger. Analysis by techniques including FTIR, XPS and 13C CP MAS NMR confirmed the effective immobilization of the enzyme on the surface of the composite support. The electrokinetic properties of the resulting systems were also determined. Results obtained from elemental analysis and by the Bradford method enabled the determination of optimum parameters for the immobilization process. Based on the hydrolysis reaction of para-nitrophenyl palmitate, a determination was made of the catalytic activity, thermal and pH stability, and reusability. The systems with immobilized enzymes were found to have a hydrolytic activity of 5.72 mU, and increased thermal and pH stability compared with the native lipase. The products were also shown to retain approximately 80% of their initial catalytic activity, even after 20 reaction cycles. The immobilization process, using a cheap, non-toxic matrix of natural origin, leads to systems with potential applications in wastewater remediation processes and in biosensors.

Nanostructured supports for multienzyme co-immobilization for biotechnological applications: Achievements, challenges and prospects.

The synergistic combination of current biotechnological and nanotechnological research has turned to multienzyme co-immobilization as a promising concept to design biocatalysis engineering. It has also intensified the development and deployment of multipurpose biocatalysts, for instance, multienzyme co-immobilized constructs, via biocatalysis/protein engineering to scale-up and fulfil the ever-increasing industrial demands. Considering the characteristic features of both the loaded multienzymes and nanostructure carriers, i.e., selectivity, specificity, stability, resistivity, induce activity, reaction efficacy, multi-usability, high catalytic turnover, optimal yield, ease in recovery, and cost-effectiveness, multienzyme-based green biocatalysts have become a powerful norm in biocatalysis/protein engineering sectors. In this context, the current state-of-the-art in enzyme engineering with a synergistic combination of nanotechnology, at large, and nanomaterials, in particular, are significantly contributing and providing robust tools to engineer and/or tailor enzymes to fulfil the growing catalytic and contemporary industrial needs. Considering the above critics and unique structural, physicochemical, and functional attributes, herein, we spotlight important aspects spanning across prospective nano-carriers for multienzyme co-immobilization. Further, this work comprehensively discuss the current advances in deploying multienzyme-based cascade reactions in numerous sectors, including environmental remediation and protection, drug delivery systems (DDS), biofuel cells development and energy production, bio-electroanalytical devices (biosensors), therapeutical, nutraceutical, cosmeceutical, and pharmaceutical oriented applications. In conclusion, the continuous developments in nano-assembling the multienzyme loaded co-immobilized nanostructure carriers would be a unique way that could act as a core of modern biotechnological research.

Evaluation of MxOy/fucoidan hybrid system and their application in lipase immobilization process.

In this work, new MxOy/fucoidan hybrid systems were fabricated and applied in lipase immobilization. Magnesium (MgO) and zirconium (ZrO2) oxides were used as MxOy inorganic matrices. In the first step, the proposed oxides were functionalized with fucoidan from Fucus vesiculosus (Fuc). The obtained MgO/Fuc and ZrO2/Fuc hybrids were characterized by means of spectroscopic analyses, including Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance. Additionally, thermogravimetric analysis was performed to determine the thermal stability of the hybrids. Based on the results, the mechanism of interaction between the oxide supports and fucoidan was also determined. Furthermore, the fabricated MxOy/fucoidan hybrid materials were used as supports for the immobilization of lipase from Aspergillus niger, and a model reaction (transformation of p-nitrophenyl palmitate to p-nitrophenol) was performed to determine the catalytic activity of the proposed biocatalytic system. In that reaction, the immobilized lipase exhibited high apparent and specific activity (145.5 U/gcatalyst and 1.58 U/mgenzyme for lipase immobilized on MgO/Fuc; 144.0 U/gcatalyst and 2.03 U/mgenzyme for lipase immobilized on ZrO2/Fuc). The immobilization efficiency was also confirmed using spectroscopic analyses (FTIR and XPS) and confocal microscopy.

Catalytic and Physicochemical Evaluation of a TiO2/ZnO/Laccase Biocatalytic System: Application in the Decolorization of Azo and Anthraquinone Dyes.

A TiO2/ZnO oxide system was proposed as a support for the immobilization of laccase from Trametes versicolor (LTV). The obtained TiO2/ZnO/LTV biocatalytic system was then applied in the decolorization/degradation of C.I. Reactive Black 5 and C.I. Acid Green 25 dyes. The efficiency of immobilization was evaluated based on catalytic properties (Bradford method, oxidation reaction of 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) and physicochemical (spectroscopic, porous, electrokinetic) analysis. The immobilization process was carried out with high performance (99.4%). Immobilized laccase retained about 40% of its activity in the whole analyzed temperature range and after 10 reaction cycles. Immobilization efficiency was also indirectly confirmed by the presence of characteristic functional groups (-C-H and -C-O), nitrogen and carbon on the TiO2/ZnO/LTV biocatalytic surface, identified by spectroscopic analyses. The increase in the surface area to 126 m2/g, change of isoelectric point (2.0) and zeta potential ranges (from +12.0 to -20.0 mV) after the immobilization process were also observed. The results show that the designed biocatalytic system enables the removal of acid dyes (C.I. Reactive Black 5 and C.I. Acid Green 25) with high efficiency (99% and 70%, respectively). Mass spectroscopy analysis indicated possible degradation products formed by the cleavage of N=N and C-N bonds.

Physicochemical and catalytic properties of acylase I from aspergillus melleus immobilized on amino- and carbonyl-grafted stöber silica.

Acylase I from Aspergillus melleus was immobilized on supports consisting of unmodified and modified silica. Modification was performed using 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA). The effectiveness of immobilization was investigated using the standard Bradford method in addition to a number of physicochemical techniques, including spectroscopic methods (FTIR, 29 Si and 13 C CP MAS NMR), porous structure and elemental analysis, and zeta potential measurement. A determination of catalytic activity was made based on the deacetylation reaction of N-acetyl-l-methionine. Furthermore, the effect of pH and temperature on the catalytic activity of the free and immobilized enzyme, as well as the reusability of the silica-bound aminoacylase, were determined. The immobilized systems demonstrated a high degree of catalytic activity. The best catalytic parameters were those of aminoacylase immobilized on silica modified with APTES (apparent activity 3937 U/g, relative activity 61.6%). © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:767-777, 2018.

Zinc Oxide-From Synthesis to Application: A Review.

Zinc oxide can be called a multifunctional material thanks to its unique physical and chemical properties. The first part of this paper presents the most important methods of preparation of ZnO divided into metallurgical and chemical methods. The mechanochemical process, controlled precipitation, sol-gel method, solvothermal and hydrothermal method, method using emulsion and microemulsion enviroment and other methods of obtaining zinc oxide were classified as chemical methods. In the next part of this review, the modification methods of ZnO were characterized. The modification with organic (carboxylic acid, silanes) and inroganic (metal oxides) compounds, and polymer matrices were mainly described. Finally, we present possible applications in various branches of industry: rubber, pharmaceutical, cosmetics, textile, electronic and electrotechnology, photocatalysis were introduced. This review provides useful information for specialist dealings with zinc oxide.