Journal of Enzymes For A New Applicable Knowledge

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Olive mill wastewater anaerobically digested : phenolic compounds with antiradical activity

The recovery of phenolic compounds, present in the olive fruits and its by-products, has been intensively studied by the antioxidant properties. Olive mill wastewater (OMW) is a phenolic-rich industrial effluent that can be advantageously valorized by the anaerobic digestion to the methane and agricultural fertilizer productions. The objective of this work was to evaluate the antiradical activity of OMW after anaerobic digestion in order to maximize the valorization of this type of effluents. The digested flow was obtained from an anaerobic hybrid reactor treating OMW at different organic loading rates (OLR), from 3.3 to 7.1 kg COD m3 d-1. OLR rise was applied by increasing progressively the OMW volume fraction from 8 % to 83 % in the feed mixture. The input and output streams, obtained at different OMW volume fractions, were characterized in terms of antiradical activity and phenolic compounds identification and quantification. Despite of the fraction decrease on total phenolic compounds provided by OMW anaerobic digestion, the antiradical activity is still significantly high (EC50 = 3.24) in the digested effluent. Oleuropein was the main phenolic compound present in the substrate before and after anaerobic digestion (about 15 % of the initial value). Others phenolic compounds present are: gallic acid, hydroxytyrosol, tyrosol, and quercetin. These data confirmed that, after the OMW anaerobic treatment to produce biomethane, the remaining flow yet contain useful compounds with antiradical activity

Properties of an alkali-thermo stable xylanase from Geobacillus thermodenitrificans A333 and applicability in xylooligosaccharides generation

An extracellular thermo-alkali-stable and cellulase-free xylanase from Geobacillus thermodenitrificans A333 was purified to homogeneity by ion exchange and size exclusion chromatography. Its molecular mass was 44 kDa as estimated in native and denaturing conditions by gel filtration and SDS-PAGE analysis, respectively. The xylanase (GtXyn) exhibited maximum activity at 70 °C and pH 7.5. It was stable over broad ranges of temperature and pH retaining 88 % of activity at 60 °C and up to 97 % in the pH range 7.5–10.0 after 24 h. Moreover, the enzyme was active up to 3.0 M sodium chloride concentration, exhibiting at that value 70 % residual activity after 1 h. The presence of other metal ions did not affect the activity with the sole exceptions of K+ that showed a stimulating effect, and Fe2+, Co2+ and Hg2+, which inhibited the enzyme. The xylanase was activated by non-ionic surfactants and was stable in organic solvents remaining fully active over 24 h of incubation in 40 % ethanol at 25 °C. Furthermore, the enzyme was resistant to most of the neutral and alkaline proteases tested. The enzyme was active only on xylan, showing no marked preference towards xylans from different origins. The hydrolysis of beechwood xylan and agriculture-based biomass materials yielded xylooligosaccharides with a polymerization degree ranging from 2 to 6 units and xylobiose and xylotriose as main products. These properties indicate G. thermodenitrificans A333 xylanase as a promising candidate for several biotechnological applications, such as xylooligosaccharides preparation

Innovative enzymes for bioethanol production from lignocellulosic materials

The general aim of this work was to add new knowledge on novel hemicellulolytic enzymes involved in the hydrolysis of lignocellulosic materials, considered as a key process for the bioethanol production. Therefore, it is not only focused on (hemi)cellulolytic enzymes from mesophilic fungi and bacteria but also on newly isolated and characterized xylanase and β-xylosidase from the thermophilic bacteria Geobacillus thermodenitrificans A333 and Anoxybacillus sp. 3M, respectively. The covered fields involved the production and purification of the novel thermo-alkali tolerant hemicellulases and the characterization of these enzymes by their activity, substrate specificity and hydrolytic potential. The present work was also focused on the definition of enzymatic cocktails through the identification of the enzyme components of bacterial and fungal origin most useful for improving the complete hydrolysis of lignocelluloses and the exploration of the possible synergies among them. In order to convert lignocellulosic materials from agro-residues into reducing sugars, pretreatments and enzymatic hydrolysis of the biomasses has been performed. Different enzyme cocktails composition were defined by using various commercial and in house developed cellulases, xylanases, β-xylosidases and arabinosidases, to obtain the efficient hydrolysis of Arundo donax, corn cobs and BSG. Since each biomass responds differently to pretreatment methods, an appropriate chemical pretreatment method was used for BSG and two different pretreatments involving chemical and physical methods were tested for their efficiency on A. donax. Though research about the conversion of biomass to ethanol is vast and this productive process is since long time known, its commercialization is restricted by the elevated costs and the limited efficiency. This research intends to demonstrate that using agro-residues as substrates, high yields of reducing sugars are possible, using the appropriate pretreatments and enzyme cocktails. The removal of the limitation imposed by poor yields after the enzymatic hydrolysis, would result in an increased efficiency for ethanol production, which is a key stepping stone to its commercialization. Also, increasing the recovery of the co-product of (hemi)celluloses hydrolysis, as xylose and arabinose, would also allow an effective utilization of this resource

Bagnoli Urban Regeneration through Phytoremediation

The Bagnolidistrict in Naples has needed urban redevelopmentfor many years. The area is not only affected by pollution caused by many industries but also by environmental pollutants, according togeognostic surveys that have found numerous contaminantsin the subsoil and water.Currently, the combination of an urban rehabilitation processwith the phytodepuration technique may represent a successful idea for obtaining bothurban regenerationand environmental remediation. Phytoremediation, a biologically based technology, has attracted the attention of both thepublic and scientists as a low-cost alternative for soil requalification. The use of plants as well as the microorganisms present in their root systems plays an important role in the ecological engineering field in controlling and reducing pollutants present in theair, water and soil.The result is efficient, sustainable and cost-effective environmental recovery compared to conventional chemical–physical techniques. In this way, not only the environmental recovery of SIN Bagnoli-Corogliocan be obtained, but also the regeneration of its landscape

Moving towards Biofuels and High-Value Products through Phytoremediation and Biocatalytic Processes

Phytoremediation is an eco-friendly technology that utilizes plants and plant–microbe interactions to remove a wide spectrum of organic and inorganic pollutants from contaminated environments such as soils, waters and sediments. This low-impact, environmentally sustainable and cost-effective methodology represents a valuable alternative to expensive physical and chemical approaches, characterized by secondary pollution risks, and is gaining increasing attention from researchers and popular acceptance. In this review, the main mechanisms underlying the decontamination activity of plants have been clarified, highlighting the environmental remediation in fertility and soil health. Studies have illustrated the high potential of phytoremediation coupled with green and sustainable biocatalytic processes, which together represent a non-polluting alternative for the conversion of plant biomass into renewable resources. The convenience of this technology also lies in the valorization of the bio-wastes towards biofuels, energy purposes and value-added products, contributing to an effective and sustainable circular approach to phyto-management. The strategy proposed in this work allows, with the use of totally green technologies, the recovery and valorization of contaminated soil and, at the same time, the production of bioenergy with high efficiency, within the framework of international programs for the development of the circular economy and the reduction of greenhouse carbon emissions

Plastid Transformation: New Challenges in the Circular Economy Era

In a circular economy era the transition towards renewable and sustainable materials is very urgent. The development of bio-based solutions, that can ensure technological circularity in many priority areas (e.g., agriculture, biotechnology, ecology, green industry, etc.), is very strategic. The agricultural and fishing industry wastes represent important feedstocks that require the development of sustainable and environmentally-friendly industrial processes to produce and recover biofuels, chemicals and bioactive molecules. In this context, the replacement, in industrial processes, of chemicals with enzyme-based catalysts assures great benefits to humans and the environment. In this review, we describe the potentiality of the plastid transformation technology as a sustainable and cheap platform for the production of recombinant industrial enzymes, summarize the current knowledge on the technology, and display examples of cellulolytic enzymes already produced. Further, we illustrate several types of bacterial auxiliary and chitinases/chitin deacetylases enzymes with high biotechnological value that could be manufactured by plastid transformation

Tobacco Plastid Transformation as Production Platform of Lytic Polysaccharide MonoOxygenase Auxiliary Enzymes

Plant biomass is the most abundant renewable resource in nature. In a circular economy perspective, the implementation of its bioconversion into fermentable sugars is of great relevance. Lytic Polysaccharide MonoOxygenases (LPMOs) are accessory enzymes able to break recalcitrant polysaccharides, boosting biomass conversion and subsequently reducing costs. Among them, auxiliary activity of family 9 (AA9) acts on cellulose in synergism with traditional cellulolytic enzymes. Here, we report for the first time, the production of the AA9 LPMOs from the mesophilic Trichoderma reesei (TrAA9B) and the thermophilic Thermoascus aurantiacus (TaAA9B) microorganisms in tobacco by plastid transformation with the aim to test this technology as cheap and sustainable manufacture platform. In order to optimize recombinant protein accumulation, two different N-terminal regulatory sequences were used: 5′ untranslated region (5′-UTR) from T7g10 gene (DC41 and DC51 plants), and 5′ translation control region (5′-TCR), containing the 5′-UTR and the first 14 amino acids (Downstream Box, DB) of the plastid atpB gene (DC40 and DC50 plants). Protein yields ranged between 0.5 and 5% of total soluble proteins (TSP). The phenotype was unaltered in all transplastomic plants, except for the DC50 line accumulating AA9 LPMO at the highest level, that showed retarded growth and a mild pale green phenotype. Oxidase activity was spectrophotometrically assayed and resulted higher for the recombinant proteins without the N-terminal fusion (DC41 and DC51), with a 3.9- and 3.4-fold increase compared to the fused proteins