New trends in industrial biocatalysis

The “manufacture and modification” of molecules in nature are catalyzed by enzymes with exquisite selectivity, unparalleled rate acceleration and under “mild” reaction conditions. Nowadays, enzyme-catalyzed synthesis is an attractive and eco-friendly alternative to the traditional multi-step and contaminating chemical processes

Biotechnological and biomedical applications of enzymes involved in the synthesis of nucleosides and nucleotides

Nucleic acid derivatives are involved in cell growth and replication, but they are also particularly important as building blocks for RNA and DNA synthesis. In nature, purine and pyrimidine nucleotides are synthesized through two distinct pathways, de novo and salvage pathways, both depending on 5-phospho-α-D-ribose 1-diphosphate (PRPP) as a key element [1,2]. In the de novo pathway, purine and pyrimidine nucleotides are synthesized from simple molecules such as glycine, glutamine, or aspartate. In contrast, the salvage pathway employs scavenged preformed endogenous or exogenous nucleobases to generate the corresponding nucleoside-50 -monophosphates (NMPs) [3]. Both metabolic routes, de novo and salvage pathways, lead to the synthesis of NMPs, which are subsequently phosphorylated to obtain the corresponding nucleoside-50 -di (NDPs) and triphosphates (NTPs). Moreover, all organisms also generate (20 -deoxy)nucleoside-50 -diphosphates (dNDPs) from NDPs [4], which will be converted to 20 -deoxyribonucleotides (dNTPs), as precursors for DNA synthesis. Additionally, nucleotide derivatives are involved in cell signaling (cyclic nucleotides, cNMPs or c-di-NMPs) [5] and a multitude of different biochemical processes, acting as cofactors (NADP+ ) or energy sources (ATP)

New trends in the biocatalytic production of nucleosidic active pharmaceutical ingredients using 2′-deoxyribosyltransferases

Nowadays, pharmaceutical industry demands competitive and eco-friendly processes for active pharmaceutical ingredients (APIs) manufacturing. In this context, enzyme and whole-cell mediated processes offer an efficient, sustainable and cost-effective alternative to the traditional multi-step and environmentally-harmful chemical processes. Particularly, 2′-deoxyribosyltransferases (NDTs) have emerged as a novel synthetic alternative, not only to chemical but also to other enzyme-mediated synthetic processes. This review describes recent findings in the development and scaling up of NDTs as industrial biocatalysts, including the most relevant and recent examples of single enzymatic steps, multienzyme cascades, chemo-enzymatic approaches, and engineered biocatalysts. Finally, to reflect the inventive and innovative steps of NDT-mediated bioprocesses, a detailed analysis of recently granted patents, with specific focus on industrial synthesis of nucleoside-based APIs, is hereunder presented

Magnetic micro-macro biocatalysts applied to industrial bioprocesses

The use of magnetic biocatalysts is highly beneficial in bioprocesses technology, as it allows their easy recovering and enhances biocatalyst lifetime. Thus, it simplifies operational processing and increases efficiency, leading to more cost-effective processes. The use of small-size matrices as carriers for enzyme immobilization enables to maximize surface area and catalysts loading, also reducing diffusion limitations. As highly expensive nanoparticles (nm size) usually aggregate, their application at large scale is not recommended. In contrast, the use of magnetic micro-macro (µm-mm size) matrices leads to more homogeneous biocatalysts with null or very low aggregation, which facilitates an easy handling and recovery. The present review aims to highlight recent trends in the application of medium-to-high size magnetic biocatalysts in different areas (biodiesel production, food and pharma industries, protein purification or removal of environmental contaminants). The advantages and disadvantages of these above-mentioned magnetic biocatalysts in bioproces

Enzyme or whole cell immobilization for efficient biocatalysis: focusing on novel supporting platforms and immobilization techniques

Biocatalysts represented by enzymes and enzyme-containing whole cells are generally fragile and easily inactivated in practical application conditions. The immobilization concept and techniques have been recognized as classic and powerful strategy for tackling such challenges (Hanefeld et al., 2009). Based on this background, a special Research Topic entitled Enzyme or Whole Cell Immobilization for Efficient Biocatalysis: Focusing on Novel Supporting Platforms and Immobilization Techniques had been organized and presented in the platform of Frontiers in Bioengineering and Biotechnology, which aimed to collect different insights and latest findings regarding but not limited to new theories, techniques and methodologies in this area. Over the past year since Sept. 2019, this Research Topic has attracted 242 authors from more than 10 countries to participate and contribute their manuscripts. Consequently, this special issue has selected and presented 40 peer-reviewed articles to meet the readers, including 31 Original Researches, four Brief Research Reports, four Reviews, and one General Commentary, which involved various aspects and every corner of this area

Taylor-made production of pyrimidine nucleoside-5′-monophosphate analogues by highly stabilized mutant uracil phosphoribosyltransferase from Toxoplasma gondii

Nowadays, enzymatic synthesis of nucleotides is an efficient and sustainable alternative to chemical methodologies. In this regard, after the biochemical characterization of wild-type and mutant uracil phosphoribosyltransferases from Toxoplasma gondii (TgUPRT, TgUPRT2, and TgUPRT3), TgUPRT2 was selected as the optimal candidate (69.5 IU mg−1, UMP synthesis) for structure-guided immobilization onto Ni2+ chelate (MNiUPRT2) and onto glutaraldehyde-activated microparticles (MGlUPRT2). Among resulting derivatives, MNiUPRT23 (6127 IU g−1biocat; 92% retained activity; 3–5 fold enhanced stability at 50–60 °C) and MGlUPRT2N (3711 IU g−1biocat; 27% retained activity; 8–20 fold enhanced stability at 50–60 °C) displayed the best operability. Moreover, the enzymatic synthesis of different pyrimidine NMPs was performed. Finally, the reusability of both derivatives in 5-FUMP synthesis (MNiUPRT23, 80% retained activity after 7 cycles, 5 min; MGlUPRT2N, 70% retained activity after 10 cycles, 20 min) was carried out at short times. © 2021 Elsevier Lt

Recent advances in bioprocess technology-2020

Now-a-days, bioprocesses catalyzed by the whole cells and enzymes in industrial settings are gaining momentum over the traditional chemical synthetic processes. In this context, biotransformations show many advantages, such as one-pot reactions under mild conditions, high stereo- and regioselectivity, environmental friendliness and broad portfolio of substrates (including liquid, solid and gas waste). Nonetheless, some limitations such as the instability of biocatalysts and poor performance under certain reaction conditions, the low solubility of some substrates in the reaction medium, the high production costs due to complex downstream processing and product isolation and the limited knowledge in the microbiology or design of the bioprocesses, often hinder the scale-up of bioprocesses from the laboratory to the manufacturing plant. To develop efficient, sustainable and low-cost processes, both industrial and environmental biotechnology have an increasing demand for novel bioprocesses, capable of overcoming the abovementioned drawbacks. In this sense, the industrial sector demands novel processes using biocatalysts that exhibit a superior activity and stability under a wide range of reaction conditions (often achieved using metabolic engineering), the optimization of feedstock utilization by employing low-cost waste resources, the use of green chemistry solutions that allow the reduction of the use of hazardous solvents and reagents, or the development of cost-competitive biorefinery concepts able to convert industrial waste and byproducts into added value products, thus creating new value chains. This special issue (SI) aims at highlighting the recent advances in Bioprocess Technology. To this end, twenty-eight scientific articles, including experimental and review papers, were compiled in order to show the reader the state-of-the-art and future trends in bioprocess technology in the context of circular economy. These papers have been selected based on the standard peer-review process of the journal and have been classified in six different categories: i) Bioprocess design and circular economy, ii) Biotransformation catalyzed by whole cell or enzymes, iii) Microbial biomass valorization into high-value chemicals and biofuels, iv) The use of renewable carbon and waste resources, v) Novel fermentation strategies, v) Metabolic engineering and vi) New bioprocesses applications. The guest editors would like to thank Prof. Ashok Pandey, Editor-in-Chief of Bioresource Technology who has contributed greatly to the success of this special issue. We also thank to Dr. Adam Fraser (Publishing Editor), Mr. Leonard Daniel (Journal Manager) and Ms. Hannah Zhang (Associate Publishing Content Specialist) for their cooperation in bringing out this SI. Finally, the guest editors would like to thank to all the authors and reviewers for their remarkable contributions, which made possible the publication of this special issue. We hope that the articles published in this Special Issue will be of great interest and value to the readers of Bioresource Technology

Fuentes de información especializadas en violencia de género

Recopilación de fuentes de información nacionales e internacionales sobre violencia de género

Identification of a novel tailor-made chitinase from white shrimp fenneropenaeus merguiensis

Fenneropenaeus merguiensis (commonly named banana shrimp) is one of the most important farmed crustacean worldwide species for the fisheries and aquaculture industry. Besides its nutritional value, it is a good source of chitinase, an enzyme with excellent biological and catalytic properties for many industrial applications. In the present study, a putative chitinase-encoding cDNA was synthesized from mRNA from F. merguiensis hepatopancreas tissue. Subsequently, the corresponding cDNA was cloned, sequenced and functionally expressed in Escherichia coli, and the recombinant F. merguiensis chitinase (rFmCHI) was purified by His-tag affinity chromatography. The bioinformatics analysis of aminoacid sequence of rFmCHI displayed a cannonical multidomain architecture in chitinases which belongs to glycoside hydrolase family 18 (GH18 chitinase). Biochemical characterization revealed rFmCHI as a monomeric enzyme of molecular weight 52 kDa with maximum activity at 40 °C and pH 6.0 Moreover, the recombinant enzyme is also stable up to 60 °C, and in the pH range 5.0-8.0. Steady-state kinetic studies for colloidal chitin revealed KM, Vmax and kcat values of 78.18 μM, 0.07261 μM. min−1 and 43.37 s−1, respectively. Overall, our results aim to demonstrate the potential of rFmCHI as suitable catalyst for bioconversion of chitin waste

Análisis de la estructura porosa y ciclo de vida de morteros de reparación en base cemento con polímeros

Los morteros de reparación deben ser capaces de reproducir, o incluso superar, las prestaciones del soporte en términos de resistencia y durabilidad. Además, los morteros de reparación deben tener una adherencia al soporte suficiente para garantizar el buen comportamiento de la estructura reparada. Se presentan los resultados de una campaña experimental llevada a cabo con dos morteros de reparación de base cemento, uno de los cuales ha sido formulado con un contenido de polímero de un 3,2% de la masa total. Los morteros han sido evaluados conforme a los estándares de la norma europea UNE-EN 1504 para morteros estructurales R4; además, se ha estudiado el comportamiento de ambos morteros en estado fresco y su estructura porosa y microestructura mediante porosimetría por intrusión de mercurio; adicionalmente, se han realizado ensayos de propiedades durables. Los resultados obtenidos indican un refinamiento de poros en el mortero con polímeros, mejorando sus prestaciones. Por último, se incluye un análisis comparativo del ciclo de vida de ambos morteros en dos ambientes con distinto nivel de agresividad, con objeto de evaluar la sostenibilidad y la repercusión a lo largo de la vida útil de la incorporación de polímero a los morteros de reparación