WHO’S AFRAID OF THE BIG BAD WOLF? IS E-LEARNING EDUCATION SUCH A HUGE THREAT NOWADAYS?

Technology is something that we’ve been taking for granted for quite a while now. We cannot imagine our lives without a smart phone or without spending hours online chatting with friends, searching for information, staying up-to-date with the latest news. However, when it comes to online education, reluctance, mistrust and suspicion are the key words normally and constantly associated with it. My paper, as a consequence, attempts to debunk the negative opinions that have grown up around E-learning methods and activities, focusing on the usefulness and effectiveness of such multimedia courses. It also intends to differentiate between different age groups or types of learners in order to emphasise the suitability of online training options in education for certain categories of learners

Criteria for Engineering Cutinases: Bioinformatics Analysis of Catalophores

Cutinases are bacterial and fungal enzymes that catalyze the hydrolysis of natural cutin, a three-dimensional inter-esterified polyester with epoxy-hydroxy fatty acids with chain lengths between 16 and 18 carbon atoms. Due to their ability to accept long chain substrates, cutinases are also effective in catalyzing in vitro both the degradation and synthesis of several synthetic polyesters and polyamides. Here, we present a bioinformatics study that intends to correlate the structural features of cutinases with their catalytic properties to provide rational basis for their effective exploitation, particularly in polymer synthesis and biodegradation. The bioinformatics study used the BioGPS method (Global Positioning System in Biological Space) that computed molecular descriptors based on Molecular Interaction Fields (MIFs) described in the GRID force field. The information was used to generate catalophores, spatial representations of the ability of each enzymatic active site to establish hydrophobic and electrostatic interactions. These tools were exploited for comparing cutinases to other serine-hydrolases enzymes, namely lipases, esterases, amidases and proteases, and for highlighting differences and similarities that might guide rational engineering strategies. Structural features of cutinases with their catalytic properties were correlated. The \u201ccatalophore\u201d of cutinases indicate shared features with lipases and esterases

Recyclable solid-phase biocatalyst with improved stability by sol–gel entrapment of β-d-galactosidase

Abstract β-d-Galactosidase from Kluyveromyces lactis was for the first time immobilized by entrapment in hybrid organic-inorganic sol–gel materials with microporous structure, obtained from alkoxy silanes and alkyl substituted alkoxy silanes, in different combinations. The immobilization matrix was tailored by fine tuning of several parameters, such as: nature of alkyl group of silane precursors, molar ratio of silane precursors, nature of additives, protein concentration. Unlike other enzymes, β-d-galactosidase showed the best catalytic activity at low alkyl group content in the sol–gel matrix, at a molar ratio of 7:1 between the tetraalkoxysilane alkyl-trialkoxysilane precursor. The immobilized enzyme demonstrated enhanced storage, pH and thermal stability compared to the soluble enzyme. The composite sol–gel materials were characterized by transmission electron microscopy, scanning electron microscopy, fluorescence confocal microscopy, and porosity measurement. The biocatalyst was successfully reused in five reaction cycles, maintaining more than 60% of the initial activity

Effect of Binding Modules Fused to Cutinase on the Enzymatic Synthesis of Polyesters

open9In relation to the development of environmentally-friendly processing technologies for the continuously growing market of plastics, enzymes play an important role as green and sustainable biocatalysts. The present study reports the use of heterogeneous immobilized biocatalysts in solvent-free systems for the synthesis of aliphatic oligoesters with Mws and monomer conversions up to 1500 Da and 74%, respectively. To improve the accessibility of hydrophilic and hydrophobic substrates to the surface of the biocatalyst and improve the reaction kinetic and the chain elongation, two different binding modules were fused on the surface of cutinase 1 from Thermobifida cellulosilytica. The fusion enzymes were successfully immobilized (>99% of bound protein) via covalent bonding onto epoxy-activated beads. To the best of our knowledge, this is the first example where fused enzymes are used to catalyze transesterification reactions for polymer synthesis purposes.openFerrario, Valerio; Todea, Anamaria; Wolansky, Lisa; Piovesan, Nicola; Guarneri, Alice; Ribitsch, Doris; Guebitz, Georg M.; Gardossi, Lucia; Pellis, AlessandroFerrario, Valerio; Todea, Anamaria; Wolansky, Lisa; Piovesan, Nicola; Guarneri, Alice; Ribitsch, Doris; Guebitz, Georg M.; Gardossi, Lucia; Pellis, Alessandr

Understanding Marine Biodegradation of Bio-Based Oligoesters and Plasticizers

The study reports the enzymatic synthesis of bio-based oligoesters and chemo-enzymatic processes for obtaining epoxidized bioplasticizers and biolubricants starting from cardoon seed oil. All of the molecules had MW below 1000 g mol-1 and were analyzed in terms of marine biodegradation. The data shed light on the effects of the chemical structure, chemical bond lability, thermal behavior, and water solubility on biodegradation. Moreover, the analysis of the biodegradation of the building blocks that constituted the different bio-based products allowed us to distinguish between different chemical and physicochemical factors. These hints are of major importance for the rational eco-design of new benign bio-based products. Overall, the high lability of ester bonds was confirmed, along with the negligible effect of the presence of epoxy rings on triglyceride structures. The biodegradation data clearly indicated that the monomers/building blocks undergo a much slower process of abiotic or biotic transformations, potentially leading to accumulation. Therefore, the simple analysis of the erosion, hydrolysis, or visual/chemical disappearance of the chemical products or plastic is not sufficient, but ecotoxicity studies on the effects of such small molecules are of major importance. The use of natural feedstocks, such as vegetable seed oils and their derivatives, allows the minimization of these risks, because microorganisms have evolved enzymes and metabolic pathways for processing such natural molecules

Biodegradable Oligoesters of ε-Caprolactone and 5-Hydroxymethyl-2-Furancarboxylic Acid Synthesized by Immobilized Lipases

Following the latest developments, bio-based polyesters, obtained from renewable raw materials, mainly carbohydrates, can be competitive for the fossil-based equivalents in various industries. In particular, the furan containing monomers are valuable alternatives for the synthesis of various new biomaterials, applicable in food additive, pharmaceutical and medical field. The utilization of lipases as biocatalysts for the synthesis of such polymeric compounds can overcome the disadvantages of high temperatures and metal catalysts, used by the chemical route. In this work, the enzymatic synthesis of new copolymers of ε-caprolactone and 5-hydroxymethyl-2-furancarboxylic acid has been investigated, using commercially available immobilized lipases from Candida antarctica B. The reactions were carried out in solvent-less systems, at temperatures up to 80 °C. The structural analysis by MALDI TOF-MS, NMR, and FT-IR spectroscopy confirmed the formation of cyclic and linear oligoesters, with maximal polymerization degree of 24 and narrow molecular weight distribution (dispersity about 1.1). The operational stability of the biocatalyst was explored during several reuses, while thermal analysis (TG and DSC) indicated a lower thermal stability and higher melting point of the new products, compared to the poly(ε-caprolactone) homopolymer. The presence of the heterocyclic structure in the polymeric chain has promoted both the lipase-catalyzed degradation and the microbial degradation. Although, poly(ε-caprolactone) is a valuable biocompatible polymer with important therapeutic applications, some drawbacks such as low hydrophilicity, low melting point, and relatively slow biodegradability impeded its extensive utilization. In this regard the newly synthesized furan-based oligoesters could represent a “green” improvement route

Azelaic Acid: A Bio-Based Building Block for Biodegradable Polymers

Azelaic acid is a dicarboxylic acid containing nine C atoms, industrially obtained from oleic acid. Besides its important properties and pharmacological applications, as an individual compound, azelaic acid has proved to be a valuable bio-based monomer for the synthesis of biodegradable and sustainable polymers, plasticizers and lubricants. This review discusses the studies and the state of the art in the field of the production of azelaic acid from oleic acid, the chemical and enzymatic synthesis of bio-based oligo and polyester and their properties, including biodegradability and biocompostability

Production of fatty acid estolides

It has been found that esterification of a hydroxy-fatty acid by a lipase can be coupled with oleate hydratase (OHase) generation of that hydroxy-FA from an unsaturated FA with a cis C9-C10 double bond, e.g. oleic acid, in a single aqueous buffered reaction medium at low temperature,e.g. 30° C. A simple one-pot enzymatic method to produce fatty acid estolides from one or more triglycerides, e.g. starting from a natural plant oil, is thereby enabled in which the same lipase catalyses both the initial hydrolysis of triglyceride and the final esterification step

Azelaic Acid: A Bio-Based Building Block for Biodegradable Polymers

The production of fine chemicals, new materials and products from renewable feedstocks represents a continuous challenge. Several procedures have been reported in the literature or patented in the last decade for the main biomass components: carbohydrates (75%), lignins (20%), fats and oils (5%) [1]. Regarding oleochemical developments, the oxidative cleavage of unsaturated fatty acids to produce dicarboxylic acids, hydroxy acids, and amino acids has received great attention in the last decade [2]. Two main oleochemical products obtained by the cleavage of unsaturated fatty acids are sebacic acid and azelaic acid. Azelaic acid (AzA) is a naturally occurring saturated nine carbon atom dicarboxylic acid found in whole grains, wheat, rye and barley [2], first detected in rancid fats. It can be formed endogenously from substrates such as longer-chain dicarboxylic acids and processes like the metabolism of oleic acid, and ψ-oxidation of monocarboxylic acids. The azelaic acid market is predicted to reach USD 160 million by 2023 and the applications include pharmacological ingredients, polymers, plastics, lubricants and materials for electronics [3]. The aim of the present review is to highlight the potential of azelaic acid as powerful building block for the synthesis of bio-based and biodegradable polymers, with a special emphasis on the green synthetic routes, embracing both chemical and enzymatic methods

Production of fatty acid estolides

It has been found that esterification of a hydroxy-fatty acid by a lipase can be coupled with oleate hydratase (OHase) generation of that hydroxy-FA from an unsaturated FA with a cis C9-C10 double bond, e.g. oleic acid, in a single aqueous buffered reaction medium at low temperature,e.g. 30° C. A simple one-pot enzymatic method to produce fatty acid estolides from one or more triglycerides, e.g. starting from a natural plant oil, is thereby enabled in which the same lipase catalyses both the initial hydrolysis of triglyceride and the final esterification step