Pilot-plant cultivation of Streptomyces griseus producing homologues of nonactin by precursor-directed biosynthesis and their identification by LC/MS-ESI

Abstract

Precursor-directed biogenetic approach was used to produce a range of nonactin homologues in a 50 l fermentor cultivation of strain Streptomyces griseus 34/249 obtained by UV mutagenesis. The production medium contained sodium propionate, isobutyrate and isovalerate as individual precursors, and 10 g l À1 Diaion HP20 styrene-divinylbenzene resin that maintains suitable precursor concentration by reversibly adsorbing and releasing it. The produced nonactin homologues were separated on two C18 reversed-phase liquid chromatography columns in series and analyzed by MS with ESI source in the positive ion mode. Formation of doubly charged ions was suppressed by an excess of Na + ions throughout the process. The production of the homologues increased up to day 5 and then it leveled off. Cultivations with individual precursors yielded a total of 18 nonactin homologues whose spectrum depended on the precursor used. The total production of the homologues was lowered but their spectrum was shifted to higher-molecular-weight compounds.

Combination of high‐throughput microfluidics and FACS technologies to leverage the numbers game in natural product discovery

“…Dereplication of active fractions revealed the presence of the macrotetrolides nonactin, monactin, dinactin and macrotetrolide G (Fig. S9 , 14–17 ) (Phillies, 1975 ; Řezanka et al ., 2010 ). Additionally, the presence of macrotetrolide D ( 18 ) was shown by molecular networking (Fig.…”

Separation of regioisomers and enantiomers of triacylglycerols containing branched fatty acids (iso and/or anteiso)

“…The cultivation of the mutant strain S. avermitilis C‐18 from the collection of the Institute of Microbiology has been described previously [16]. Similarly, as in our previous article [17], cultivation was performed in production medium containing sodium propionate, isobutyrate, and isovalerate as individual precursors at a concentration of 10 g/L. The obtained biomass was after centrifugation lyophilized, and used for extraction of total lipids.…”

“…Optical purity and other characteristics such as tR, m/z value of DAGs ions, abundance of these ions or ECN (effective carbon number) are given in Table 2. Another method used to identify relevant molecular species of TAGs was to use the ability of S. avermitilis to utilize various sources of carbons [16,17]. Streptomycetes are able to biosynthesize both primary (e.g., FAs) and secondary (e.g., antibiotics) metabolites using precursor direct biosynthesis.…”