Combinatorial strategies for production improvement of anti-tuberculosis antibiotics ilamycins E1/E2 from deep sea-derived Streptomyces atratus SCSIO ZH16 ΔilaR

Abstract

Ilamycins E1/E2 are novel cyclic heptapeptides from Streptomyces atratus SCSIO ZH16, which have the MIC value of 9.8 nM against Mycobacterium tuberculosis H37Rv. However, the lower fermentative titer of ilamycins E1/E2 cut off further development for novel anti-TB lead drugs. In order to break the obstacle, the combinatorial strategy of medium optimization, fermentative parameters optimization, exogenous addition of metal ions, precursors, and surfactants was developed to promoted the production of ilamycins E1/E2. Addition of 1 mM ZnCl2 at 0 h, 1 g/L tyrosine at 96 h, and 2 g/L shikimic acid at 48 h increased the production of ilamycins E1/E2 from 13.51 to 762.50 ± 23.15, 721.39 ± 19.13, and 693.83 ± 16.86 mg/L, respectively. qRT-PCR results showed that the transcription levels of key genes in Embden–Meyerhof–Parnas pathway, hexose phosphate shunt pathway, and shikimic acid pathway were upregulated. In addition, the production of ilamycins E1/E2 reached 790.34 mg/L in a 5-L bioreactor by combinatorial strategy. Combinatorial strategies were used for improving ilamycins E1/E2 production in S. atratus ΔilaR and provided a sufficient basis on further clinic development. Graphical Abstract

Efficient ilamycins production utilizing Enteromorpha prolifera by metabolically engineered Streptomyces atratus

“…Other process parameters (temperature, liquid volume, rotational speed, etc.) optimized were consistent with our previous work [11] (Zhu et al, 2022). Another research in our lab found that addition of Zn 2+ can further improve the yield of ilamycins, and we found in this work that 1 mmol/L is the best Zn 2+ concentration for EP powder-containing medium.…”

“…By Plackett-Burman design model, single factor optimization, pH coordinated feeding and continuous pulse feeding, achieved 415.7 ± 29.2 mg/L ilamycin E yield in a 300-L bioreactor [10]. Our previous research also improved the production of ilamycin E from 13.51 to 762.50 mg/L in a 5-L bioreactor, and found the crucial role of nitrogen source on cellular growth of ZH16-ΔilaR and the production of ilamycins [11]. Soya soybean powder, the preferable nitrogen source identi ed, has obvious shortcomings such as di cult to sterilize and high cost.…”

“…After 24 hours of drying in a 50 ℃ oven, the dry weight was calculated using subtraction method. For the extraction and quantitative analysis of ilamycins by HPLC, detailed steps were performed as described previously [11]…”

Efficient ilamycins production utilizing Enteromorpha prolifera by metabolically engineered Streptomyces atratus

“…Due to the specific impact of any kind of organic nitrogen source on the growth of bacteria and synthesis of natural products, one bacterium or its genetic mutant has unique preference for organic nitrogen sources. Previous studies indicated the significant effect of the selection of organic nitrogen source on the yield of ilamycins in S. atratus SCSIO ZH16 Δ ilaR [ 7 , 24 ]. In view of this, this study started with the systematic screening of composite nitrogen sources on S .…”

“…By Plackett–Burman design model, single factor optimization, pH coordinated feeding and continuous pulse feeding, [ 7 ] achieved 415.7 ± 29.2 mg/L ilamycin E yield in a 300 L bioreactor. Our previous research also improved the production of ilamycin E from 13.51 to 762.50 mg/L in a 5 L bioreactor, and found the crucial role of nitrogen source on cellular growth of ZH16-Δ ilaR and the production of ilamycins [ 24 ]. Soybean powder, the preferable nitrogen source identified, has obvious shortcomings, such as difficult to sterilize and high cost.…”