No abstract

The aim of this study was to evaluate the efficiency of sonication in releasing protein from a widespread lipase-producing yeast, Yarrowia lipolytica KKP 379, and to examine the impact of ultrasound waves generated in a horn-type sonicator on the lipolytic activity of Y. lipolytica in the hydrolysis of p-nitrophenyl laurate. In this paper, we focused on a few parameters of ultrasound cell disruption, such as the time of sonication, acoustic power, storage time of the frozen yeast biomass used in sonication and the solvent used to suspend the yeast cells which were considered as the most important part in the process of obtaining a biocatalyst from Y. lipolytica for organic synthesis. The most effective additive in protein release proved to be 2% Tween 80; other ideal parameters of the process were ultrasonic power at 150 W for 15 min and 9 weeks of frozen biomass storage time. The sonication parameters, which were the best for protein release, did not seem to be the most effective for obtaining high lipolytic activity due to denaturation as an effect of cavitation.

No abstract

Vancomycin is a glycopeptide antibiotic that inhibits transpeptidation during cell wall synthesis by binding to the D-Ala-D-Ala termini of lipid II. For long, it has been used as a last resort antibiotic. However, since the emergence of the first vancomycin-resistant enterococci in 1987, vancomycin resistance has become widespread, especially in hospitals. We have synthesized and evaluated 110 vancomycin analogs modified at the C-terminal carboxyl group of the heptapeptide moiety with R2NHR1NH2 substituents. Through iterative optimizations of the substituents, we identified vancomycin analogs that fully restore (or even exceed) the original inhibitory activity against vancomycin-resistant enterococci (VRE), vancomycin-intermediate (VISA) and vancomycin-resistant Staphylococcus aureus (VRSA) strains. The best analogs have improved growth inhibitory activity and in vitro therapeutic indices against a broad set of VRE and methicillin-resistant S. aureus (MRSA) isolates. They also exceed the activity of vancomycin against Clostridium difficile ribotypes. Vanc-39 and Vanc-42 have a low probability to provoke antibiotic resistance, and overcome different vancomycin resistance mechanisms (VanA, VanB, and VanC1).

Three kinds of matrices (calcium alginate, gelatin, and PVA) were employed as supports to immobilize lipases from Y. lipolytica KKP 379 via physical adsorption. The stability of biocatalysts (free and immobilized) was evaluated by measuring the enzyme activity before and after treatment with the method based on the hydrolysis of p-nitrophenyl laurate. Two fractions of enzymes were immobilized: cell-bound (yeast biomass) and extracellular (supernatant). The yield of immobilization and catalytic properties of immobilized lipases were investigated. Satisfactory results for lipolytic activity and biocatalyst stability were obtained for cell-bound enzymes immobilized in alginate (0.38 U g -1 d.m.) and crosslinked gelatin (0.18 U g -1 d.m.). Immobilization of the supernatant was successful only on the alginate (0.026 U g -1 d.m.). After lyophilization, no significant difference was noticed between treated and untreated biocatalysts. Lyophilized catalysts were successfully immobilized in all three matrices, but the process reduced their lipolytic activity probably due to an insufficient amount of water in the reaction solution.

Techniki ultradźwiękowe są od dawna stosowane w przemyśle spożywczym, przede wszystkim w procesach przetwarzania i utrwalania żywności. Celem pracy była ocena sonifikacji jako alternatywnej metody inaktywacji komórek drożdży. Dodatkowo rozważono zastosowanie sonifikacji do pozyskiwania roztworu białek wewnątrzkomórkowych. Komórki szczepu drożdży Saccharomyces cerevisiae 2200 oraz komórki świeżych drożdży piekarskich poddawano sonifikacji w głowicowym homogenizatorze ultradźwiękowym o częstotliwości 20 kHz. Zaobserwowano istotny wpływ czasu, cyklu pracy oraz mocy fali akustycznej na inaktywację komórek oraz stopień izolacji białek, które wydzielono z wydajnością 60 % ze szczepu drożdży S. cerevisiae 2200 i 43 % ze świeżych drożdży piekarskich. Dezintegracja struktury komórkowej drożdży za pomocą ultradźwięków może być dobrą laboratoryjną metodą permeabilizacji ściany komórkowej oraz izolacji białek. Liczba żywych komórek po procesie sonifikacji zmniejszyła się 100 do 1000-krotnie w porównaniu z początkowąj liczbą jtk/cm 3 , przy czym efekt ten może zostać zwielokrotniony przez połączenie działania ultradźwięków z czynnikiem termicznym.

In recent years there has been growing interest in substances with antioxidative properties, which reduce or prevent harmful effects of free radicals on living tissues, and inhibit aging processes and the development of certain diseases. The objective of this paper is to review new methods of obtaining antioxidants of plant origin and new trends in research aiming to improve their quality and profitability on an industrial scale. Among the issues discussed, there are the methods that use techniques of plant and microbial genetic engineering. A brief description of antioxidants and natural sources of their occurrence is also presented in this paper. In view of the fact that the biosynthesis of flavonoids and isoflavonoids is probably the best-known metabolic pathway of natural plant products, the review of achievements of recent years in the field of metabolic engineering was shown with the example of flavonoids. The modifications of flavonoid biosynthetic pathways were related to changes in the expression level of structural or regulatory genes, silencing of competitive genes or modifying catalytic properties of enzymes using techniques of protein engineering. The paper also presents the achievements of microorganism engineering in the field of application of fermentation processes as a source of specific flavonoid compounds, which was possible by designing the phenylpropanoid biosynthetic pathway in cells of microorganisms such as the bacterium E. coli or S. cerevisiae, baker's yeast. Both approaches can be used in the production of flavonoids attractive in terms of application.

The proportion of approved chiral drugs and drug candidates under medical studies has surged dramatically over the past two decades. As a consequence, the efficient synthesis of enantiopure pharmaceuticals or their synthetic intermediates poses a profound challenge to medicinal and process chemists. The significant advancement in asymmetric catalysis has provided an effective and reliable solution to this challenge. The successful application of transition metal catalysis, organocatalysis, and biocatalysis to the medicinal and pharmaceutical industries has promoted drug discovery by efficient and precise preparation of enantio-enriched therapeutic agents, and facilitated the industrial production of active pharmaceutical ingredient in an economic and environmentally friendly fashion. The present review summarizes the most recent applications (2008–2022) of asymmetric catalysis in the pharmaceutical industry ranging from process scales to pilot and industrial levels. It also showcases the latest achievements and trends in the asymmetric synthesis of therapeutic agents with state of the art technologies of asymmetric catalysis.