Exploring the extremes: applying high concentration of yeast extract leads to drastic morphological changes and elimination of (+)-geodin and asterric acid production in Aspergillus terreus submerged cultures

Abstract

Objective Evaluation of morphology and secondary metabolites production in Aspergillus terreus ATCC 20542 cultures over a wide range of lactose and yeast extract concentrations from 0.2 up to an extremely high level of 200 g l−l. Results The morphological differences of mycelial objects were quantified with the use of morphological parameters calculated by applying the tools of digital image analysis. At 200 g l−l of yeast extract clumps and loose hyphae were recorded instead of pellets commonly observed in submerged cultures of A. terreus. Under these conditions the biosynthesis of (+)-geodin and asterric acid was totally blocked, lovastatin formation was found to be at a relatively low level and biomass production turned out to be greater than in the remaining variants, where the pelleted growth was observed. At 200 g l−l of lactose the production of lovastatin, (+)-geodin and asterric acid was visibly stimulated compared to the media containing 0.2, 2 and 20 g l−l of the sugar substrate, but at the same time no traces of butyrolactone I could be detected in the broth. Lactose at the extremely high concentration of 200 g l−l did not induce the drastic morphological changes observed in the case of 200 g l-1 of yeast extract. It was proved that at the C/N values as low as 4 and as high as 374 A. terreus not only continued to display growth but also exhibited the production of secondary metabolites. The use of cultivation media representing the equivalent C/N ratios led to different metabolic and morphological outcomes depending on the concentration of lactose and yeast extract that contributed to the given C/N value. Conclusion The extremely high concentration of yeast extract leads to marked morphological changes of A. terreus and the elimination of (+)-geodin and asterric production, while applying the excess of lactose is stimulatory in terms of lovastatin production.

Enhanced Oxytetracycline Production by Streptomyces rimosus in Submerged Co-Cultures with Streptomyces noursei

“…Here, when the morphological results obtained for the “ S. rimosus versus S. noursei ” co-cultivation were compared with the data gathered for other (less effective) co-cultures, there was no evidence that the morphology could be a key factor determining the effectiveness of this variant. It needs to be mentioned that the morphological variations recorded in the present work should be seen as rather subtle when compared with the ones found in our previous studies, e.g., when the high concentration of yeast extract resulted in the transition from the pelleted to loose morphology in A. terreus [ 24 ] or when the star-shaped pellets were formed in aluminum oxide-supplemented bioreactor cultures of C. globosum [ 17 ].…”

Tunable population dynamics in a synthetic filamentous coculture

“…Then it was analyzed how the population dynamics can be tuned using different osmolalities, and shaking frequencies. Osmolality can alter the growth kinetics and productivity of filamentous organisms (Boruta et al, 2021 ; Wucherpfennig et al, 2011 ). Furthermore, shaking frequency and thereby power input is a crucial parameter for filamentous organisms.…”

Secondary metabolites from the deep-sea derived fungus Aspergillus terreus MCCC M28183

“…Terrein, with its 4H-furan-3-one framework, demonstrates multifaceted biological activities, including antitumor and anti-inflammatory effects, and inhibits melanin synthesis, suggesting therapeutic applications in hyper-pigmentation ( Zhao et al, 2016 ). The dihydroxyphenylalanine (DOPA) pigments, geodin and epi -geodin, are noted for their antibiotic activity and metal ion chelation capabilities ( Boruta et al, 2021 ). This spectrum of metabolites, each with unique structural and pharmacological properties, underscores the importance of Aspergillus terreus in pharmaceutical and industrial applications.…”