Identification, characterization and molecular adaptation of class I redox systems for the production of hydroxylated diterpenoids

Actinomycetes as Producers of Biologically Active Terpenoids: Current Trends and Patents

Terpenes and their derivatives (terpenoids and meroterpenoids, in particular) constitute the largest class of natural compounds, which have valuable biological activities and are promising therapeutic agents. The present review assesses the biosynthetic capabilities of actinomycetes to produce various terpene derivatives; reports the main methodological approaches to searching for new terpenes and their derivatives; identifies the most active terpene producers among actinomycetes; and describes the chemical diversity and biological properties of the obtained compounds. Among terpene derivatives isolated from actinomycetes, compounds with pronounced antifungal, antiviral, antitumor, anti-inflammatory, and other effects were determined. Actinomycete-produced terpenoids and meroterpenoids with high antimicrobial activity are of interest as a source of novel antibiotics effective against drug-resistant pathogenic bacteria. Most of the discovered terpene derivatives are produced by the genus Streptomyces; however, recent publications have reported terpene biosynthesis by members of the genera Actinomadura, Allokutzneria, Amycolatopsis, Kitasatosporia, Micromonospora, Nocardiopsis, Salinispora, Verrucosispora, etc. It should be noted that the use of genetically modified actinomycetes is an effective tool for studying and regulating terpenes, as well as increasing productivity of terpene biosynthesis in comparison with native producers. The review includes research articles on terpene biosynthesis by Actinomycetes between 2000 and 2022, and a patent analysis in this area shows current trends and actual research directions in this field.

Isolation and Investigation of Natural Rare Earth Metal Chelating Agents From Calothrix brevissima - A Step Towards Unraveling the Mechanisms of Metal Biosorption

In this study water soluble compounds that form complexes with Rare Earth Elements (REE) and other metals were isolated from Calothrix brevissima biomass with chromatographic methods for the first time. Molecular characterization showed that the isolated compounds are most likely polysaccharides comprised of arabinose, xylose, mannose, galactose and glucose. FT-IR analysis revealed functional groups involved in the binding mechanism of Tb are likely sulfate- and to a lesser extend hydroxyl-groups. The binding specificity of the isolated compounds was investigated with different metal solutions. Here, ions of the alkali and alkaline earth metals Na, K, Mg and Ca showed no competition for Tb-binding even at 10-fold excess concentration. Ions of the elements Co and Pb on the other hand replaced Tb at higher concentrations. Addition of the isolated compounds significantly reduced the precipitation of Eu at pH-values between 6.7 and 9.5, indicating that the interaction between the isolated chelators and Rare Earth Metals is stable even at high pH-values.

Unrivalled diversity: the many roles and reactions of bacterial cytochromes P450 in secondary metabolism

Covering: 2000 up to 2018 The cytochromes P450 (P450s) are a superfamily of heme-containing monooxygenases that perform diverse catalytic roles in many species, including bacteria. The P450 superfamily is widely known for the hydroxylation of unactivated C-H bonds, but the diversity of reactions that P450s can perform vastly exceeds this undoubtedly impressive chemical transformation. Within bacteria, P450s play important roles in many biosynthetic and biodegradative processes that span a wide range of secondary metabolite pathways and present diverse chemical transformations. In this review, we aim to provide an overview of the range of chemical transformations that P450 enzymes can catalyse within bacterial secondary metabolism, with the intention to provide an important resource to aid in understanding of the potential roles of P450 enzymes within newly identified bacterial biosynthetic pathways.

Metabolic engineering and synthetic biology approaches driving isoprenoid production in Escherichia coli

Isoprenoids comprise the largest family of natural organic compounds with many useful applications in the pharmaceutical, nutraceutical, and industrial fields. Rapid developments in metabolic engineering and synthetic biology have facilitated the engineering of isoprenoid biosynthetic pathways in Escherichia coli to induce high levels of production of many different isoprenoids. In this review, the stem pathways for synthesizing isoprene units as well as the branch pathways deriving diverse isoprenoids from the isoprene units have been summarized. The review also highlights the metabolic engineering efforts made for the biosynthesis of hemiterpenoids, monoterpenoids, sesquiterpenoids, diterpenoids, carotenoids, retinoids, and coenzyme Q₁₀ in E. coli. Perspectives and future directions for the synthesis of novel isoprenoids, decoration of isoprenoids using cytochrome P450 enzymes, and secretion or storage of isoprenoids in E. coli have also been included.

Opportunities and challenges for the sustainable production of structurally complex diterpenoids in recombinant microbial systems

With over 50.000 identified compounds terpenes are the largest and most structurally diverse group of natural products. They are ubiquitous in bacteria, plants, animals and fungi, conducting several biological functions such as cell wall components or defense mechanisms. Industrial applications entail among others pharmaceuticals, food additives, vitamins, fragrances, fuels and fuel additives. Central building blocks of all terpenes are the isoprenoid compounds isopentenyl diphosphate and dimethylallyl diphosphate. Bacteria like Escherichia coli harbor a native metabolic pathway for these isoprenoids that is quite amenable for genetic engineering. Together with recombinant terpene biosynthesis modules, they are very suitable hosts for heterologous production of high value terpenes. Yet, in contrast to the number of extracted and characterized terpenes, little is known about the specific biosynthetic enzymes that are involved especially in the formation of highly functionalized compounds. Novel approaches discussed in this review include metabolic engineering as well as site-directed mutagenesis to expand the natural terpene landscape. Focusing mainly on the validation of successful integration of engineered biosynthetic pathways into optimized terpene producing Escherichia coli, this review shall give an insight in recent progresses regarding manipulation of mostly diterpene synthases.