Whole-cell biotransformation of oleanolic acid by free and immobilized cells of Nocardia iowensis: Characterization of new metabolitesIn this study, Nocardia iowensis was used to transform oleanolic acid (OA) into oleanane derivatives. The first derivative, which was found after 24 h of cultivation, was the known and already described OA methyl ester. After 1 week, two other derivatives (oleanonic acid methyl ester and an unknown metabolite) were identified as new products of a biotransformation by N. iowensis. These oleanane metabolites were characterized by HPLC, HPLC-ESI-MS, and HPLC-1 H NMR spectroscopy. The biotransformation was performed by suspended and immobilized cells (ICs) of N. iowensis. Cells immobilized in alginate beads were used in order to prepare a continuous process. The substrate uptake of free and ICs was similar, whereas the peak area of OA methyl ester of the ICs was only about 10% of the native cells. However, the final product (oleanonic acid methyl ester) concentrations were similar in both approaches, whereas the unknown metabolite 3 was only detected transiently in the medium of ICs. Based on these results, a new biosynthetic pathway for the biotechnological production of oleanonic acid methyl ester is proposed.
Diazotrophic cyanobacteria are able to fix N2 from the atmosphere and release it as bioavailable nitrogen what other organisms can utilize. Thus, they could be used as living nitrogen supplier whereby the use of fertilizer could be reduced in agricultural industry what results in a decrease of laughing gas released during fertilizer production. The diazotroph cyanobacterium Desmonostoc muscorum (D. muscorum) was characterized in shake flasks cultivated in nitrogen‐free and nitrogen‐containing medium. Similar growth rates were reached in both cultivations and the release of ammonium by D. muscorum was detected under nitrogen depletion. Subsequently, D. muscorum was co‐cultivated with Arabidopsis thaliana (A. thaliana) in nitrogen‐free medium. Additionally, the plant was cultivated in nitrogen containing and nitrogen‐free medium without D. muscorum as reference. A co‐cultivation led to higher growth rates of the cyanobacterium and similar growth of A. thaliana with similar maximum photochemical efficiency of photosystem II compared to the growth of nitrogen containing medium. Further, accumulation of cyanobacterial cells around the roots of A. thaliana was detected, indicating a successfully induced artificial symbiosis. Based on these results, D. muscorum could be a promising cyanobacterium as living nitrogen supplier for plants.
Plant in vitro cultures are a prospective alternative for biochemicals production, for example the triterpenes oleanolic and ursolic acid present in plants and cell cultures of Salvia sp. Our objective was to develop a suitable analysis protocol for evaluation of triterpenic acid yield in plant raw material and in vitro cultures supporting selection processes. Moreover, valuable bioactive compounds had to be revealed. Thus, different strategies enhancing the separation for a sensitive and effective HPLC-UV method were investigated and the developed method was validated for linearity, precision, accuracy, limits of detection and quantification. A baseline separation of these isomers enabled detection limits of below 0.4 µg/mL and quantification limits of about 1.2 µg/mL. Over the tested concentration range a good linearity was observed (R² > 0.9999). The variations in the method were below 6% for intra-and inter-day assays of concentration. Recoveries were between 85-98% for both compounds using ethanol as extraction solvent. Additionally, metabolite profiling of cell suspension culture extracts by GC-MS has shown the production variability of different plant metabolites and especially the presence of plant phenols and sterols. These studies provide a method suitable for screening plant and cell culture productivity of triterpenic acids and highlighted interesting co-products of plant cell cultures.
In the course of combining the Sustainable Development
Goals (SDGs)
with the science education curriculum, the relevance of the micro-
and macroalgae in education is based on the biotechnological future-oriented
significance and the ever-growing trend toward plant-based nutrition.
So, the micro- and macroalgae are finding their way onto the food
shelves and creating biotechnological solutions with regard to climate
change (SDG4; SDG13). Their colored photopigments and phycobiliproteins
are already established as important natural dyes in the food and
textile industries. In addition to being essential in photosynthesis,
photopigments have a variety of functions and effects that influence
almost all aspects of our lives. The article presents experimental
protocols developed based on the established methods for the extraction
of photopigments from plants and optimized for the use of phototrophic
micro- and macroalgae (Chlorella vulgaris, Arthrospira platensis, and Palmaria palmata). Besides the green chlorophylls and yellow-orange carotenoids in
plants, cyanobacteria and red algae developed additional light antenna
complexes, so-called phycobilisomes, consisting of different phycobiliproteins.
For this purpose, experiments that are simple to execute have been
developed to make the colorful world of photopigments visible to the
students from the upper secondary level and can be used in both university
and school educational settings. Furthermore, a column chromatography
was developed, which allows the preparation of the pigment and phycobiliprotein
extracts from A. platensis. This procedure is based
on the established “supermarket column” and was optimized
according to the use of powdered amounts of A. platensis. Additionally, results from a first implementation in a classroom
setting will be discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.