Publications by authors named "Robson C Alnoch"

Studies have highlighted the great potential of Oudemansiella canarii laccase in degrading synthetic dyes for reducing their toxicity. Immobilization of enzymes improves usability in degradation processes and the present work succeeded in immobilizing this laccase onto MANAE-agarose. Immobilization improved pH, thermal, and storage stabilities.

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Acetylxylan esterases (AXEs) are essential enzymes that break down the acetyl groups in acetylated xylan found in plant cell walls polysaccharides. They work synergistically with backbone-depolymerizing xylanolytic enzymes to accelerate the degradation of complex polysaccharides. In this study, we cloned the gene axeA, which encodes the acetylxylan esterase from Aspergillus nidulans FGSC A4 (AxeAN), into the pEXPYR expression vector and introduced it into the high protein-producing strain A.

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The β-glucosidase gene from Aspergillus nidulans FGSC A4 was cloned and overexpressed in the A. nidulans A773. The resulting purified β-glucosidase, named AnGH3, is a monomeric enzyme with a molecular weight of approximately 80 kDa, as confirmed by SDS-PAGE.

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In response to the escalating demand for sustainable agricultural methodologies, the utilization of microbial volatile organic compounds (VOCs) as antagonists against phytopathogens has emerged as a viable eco-friendly alternative. Microbial volatiles exhibit rapid diffusion rates, facilitating prompt chemical interactions. Moreover, microorganisms possess the capacity to emit volatiles constitutively, as well as in response to biological interactions and environmental stimuli.

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Glucoamylases are exo-enzymes that cleave the ends of the starch chain, releasing glucose units. In the current work, we described a novel 1,4-α-glucoamylase from an A. brasiliensis strain isolated from an environmental sample.

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Biological macromolecules are found in different shapes and sizes. Among these, enzymes catalyze biochemical reactions and are essential in all organisms, but is there a limit size for them to function properly? Large enzymes such as catalases have hundreds of kDa and are formed by multiple subunits, whereas most enzymes are smaller, with molecular weights of 20-60 kDa. Enzymes smaller than 10 kDa could be called microenzymes and the present literature review brings together evidence of their occurrence in nature.

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This work aimed to produce porous poly-hydroxybutyrate (PHB) pellets in order to evaluate the pellets as a support for immobilization of the metagenomic lipase, LipG9. Four types of pelletized PHB particles with different morphological characteristics were obtained using the double emulsion and solvent evaporation technique (DESE). The micropores of these PHB pellets had similar average diameters (about 3 nm), but the pellets had different specific surface areas: 11.

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Article Synopsis
  • Xylooligosaccharides (XOS) serve as important prebiotics in the food industry, requiring high purity for optimal health benefits.
  • This research focuses on immobilizing the enzyme MpXyn10, which efficiently produces XOS from eucalyptus wood.
  • The study achieved over 90% enzyme activity retention and significant XOS production using Purolite-MpXyn10, indicating its potential for practical application in biorefinery processes.
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In this work, ultrasound was used to assist the ethanolysis of castor oil in a solvent-free system, catalyzed by a dry fermented solid containing the lipase from Burkholderia contaminans (BCFS). Reactions were done at 45°C. The maximum conversion in Erlenmeyer flasks was 71% in 96 h, using a loading of 9% (mass of BCFS in relation to the mass of triacylglycerols in the castor oil) and a molar ratio of ethanol:oil of 6:1, with addition of ethanol in 12 steps.

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The climate changes expected for the next decades will expose plants to increasing occurrences of combined abiotic stresses, including drought, higher temperatures, and elevated CO atmospheric concentrations. These abiotic stresses have significant consequences on photosynthesis and other plants' physiological processes and can lead to tolerance mechanisms that impact metabolism dynamics and limit plant productivity. Furthermore, due to the high carbohydrate content on the cell wall, plants represent a an essential source of lignocellulosic biomass for biofuels production.

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The present work evaluates the immobilization of LipC12 on different supports in tandem with bioimprinting technique, in order to improve its activity and stability in organic medium. Oleic acid was selected as the bioimprinting molecule. The immobilized LipC12 was applied in the synthesis of pentyl oleate by esterification reaction and in the production of fatty acids, mono, and diglycerides via hydrolysis of triacylglycerols, in n-heptane reaction media.

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Since laccase acts specifically in lignin, the major contributor to biomass recalcitrance, this biocatalyst represents an important alternative to the pretreatment of lignocellulosic biomass. Therefore, this study investigates the laccase pretreatment and climate change effects on the hydrolytic performance of Through a Trop-T-FACE system, grew under current (Control (C)) and future climate conditions: elevated temperature (2 °C more than the ambient canopy temperature) combined with elevated atmospheric CO concentration(600 μmol mol), name as eT+eC. Pretreatment using a laccase-rich crude extract from was optimized through statistical strategies, resulting in an increase in the sugar yield of biomass (up to 57%) comparing to non-treated biomass and enabling hydrolysis at higher solid loading, achieving up to 26 g L.

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A purified exo-polygalacturonase of Neosartorya glabra (EplNg) was successfully characterized. EplNg native presented 68.2 kDa, with 32% carbohydrate content.

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The production and direct employment in organic medium in the ethyl-oleate synthesis of a fermented solid (FS) containing lipases by Penicillium roqueforti ATCC 10110 (PR10110) was investigated. For the production of this FS, the solid-state fermentation of different agroindustrial waste was used, such as: cocoa shell, sugarcane bagasse, sugarcane bagasse with cocoa shell, and cocoa shell with soybean oil and nutrient solution. The response surface methodology was used to study the effect of independent variables of initial moisture content and inductor concentration, as carbon source and inducer on lipase production.

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In recent years, metagenomic strategies have been widely used to isolate and identify new enzymes from uncultivable components of microbial communities. Among these enzymes, various lipases have been obtained from metagenomic libraries from different environments and characterized. Although many of these lipases have characteristics that could make them interesting for application in biocatalysis, relatively little work has been done to evaluate their potential to catalyze industrially important reactions.

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LipMF3 is a new lipase isolated from a metagenomic library derived from a fat-contaminated soil. It belongs to the lipase subfamily I.1 and has identities of 68% and 67% with lipases of Chromobacterium violaceum and C.

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Burkholderia contaminans LTEB11 is a Gram-negative betaproteobacterium isolated as a contaminant of a culture in mineral medium supplemented with vegetable oil. Here, we report the genome sequence of B. contaminans LTEB11, identifying and analyzing the genes involved in its lipolytic machinery and in the production of other biotechnological products.

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We review the application of dry fermented solids (DFS) containing naturally immobilized enzymes as catalysts in synthesis and in hydrolysis reactions. The most studied application is the use of DFS containing lipases in the synthesis of biodiesel esters, by transesterification of oils or by esterification of fatty acids with short-chain alcohols in solvent-free reaction media. Other applications of DFS that have been studied include the use of DFS containing pectinases to liberate D-galacturonic acid from pectin and the production of high-value compounds by DFS containing lipases, such as the synthesis of sugar esters and the production of pure enantiomers by resolution of racemic mixtures.

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Genes encoding lipase LipBC (lipA) and foldase LifBC (lipB) were identified in the genome of Burkholderia contaminans LTEB11. Analysis of the predicted amino acid sequence of lipA showed its high identity with lipases from Pseudomonas luteola (91%), Burkholderia cepacia (96%) and Burkholderia lata (97%), and classified LipBC lipase in the lipase subfamily I.2.

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Immobilization is an exciting alternative to improve the stability of enzymatic processes. However, part of the applied covalent strategies for immobilization uses specific conditions, generally alkaline pH, where some enzymes are not stable. Here, a new generation of heterofunctional supports with application at neutral pH conditions was proposed.

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In previous work, a new lipase and its cognate foldase were identified and isolated from a metagenomic library constructed from soil samples contaminated with fat. This new lipase, called LipG9, is a true lipase that shows specific activities that are comparable to those of well-known industrially-used lipases with high activity against long-chain triglycerides. In the present work, LipG9 was co-expressed and co-immobilized with its foldase, on an inert hydrophobic support (Accurel MP1000).

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