Medium optimization and subsequent fermentative regulation enabled the scaled‐up production of anti‐tuberculosis drug leads ilamycin‐E1/E2

Abstract

Background: Tuberculosis (TB) and its evolving drug resistance have exerted severe threats on the global health, hence it is still essential to develop novel anti-TB antibiotics. Ilamycin-E1/E2 is a pair of cycloheptapeptide enantiomers obtained from a marine Streptomyces atratus SCSIO ZH16-ΔilaR mutant, and has presented significant anti-TB activities as promising drug lead compounds, but their clinical development has been hampered by low fermentation titers. Main methods and major results:By applying the statistical Plackett-Burman design (PBD) model, bacterial peptone was first screened out as the only significant but negative factor to affect the ilamycin-E1/E2 production. Subsequent single factor optimization in shaking flasks revealed that the replacement of bacterial peptone with malt extract could not only eliminate the accumulation of porphyrin-type competitive byproducts but also improve the titer of ilamycin-E1/E2 from original 13.6 ± 0.8 to 142.7 ± 5.7 mg L −1 , about 10.5-fold increase. Next, a pH coordinated feeding strategy was adopted in 30 L fermentor and obtained 169.8 ± 2.5 mg L −1 ilamycin-E1/E2, but further scaled-up production in 300 L fermentor only gave a titer of 131.5 ± 7.5 mg L −1 due to the unsynchronization of feeding response and pH change. Consequently, a continuous pulse feeding strategy was utilized in 300 L fermentor to solve the above problem and finally achieved 415.7 ± 29.2 mg L −1 ilamycin-E1/E2, representing a 30.5-fold improvement.Implication: Our work has provided a solid basis to acquire sufficient ilamycin-E1/E2 lead compounds and then support their potential anti-TB drug development.

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

“…The inactivation of ilaA and overexpression of ilaB increased the total production of ilamycins to 3.0-and 1.9-fold compared to those in the wild-type S. atratus SCSIO ZH16, respectively (He et al 2020). Medium optimization and subsequent fermentative regulation strategy enabled the scaled-up production of ilamycins E 1 /E 2 to 415.7 ± 29.2 mg/L in S. atratus SCSIO ZH16 ΔilaR in a 300-L bioreactor (Fan et al 2022). However, there are few reports of titer enhancement of ilamycins E 1 /E 2 by fermentative process parameters optimization in wild-type strains and their mutants, especially.…”

“…Medium optimization and subsequent fermentative regulation strategy enabled the scaled-up production of ilamycins E 1 /E 2 to 415.7 ± 29.2 mg/L in S . atratus SCSIO ZH16 Δ ilaR in a 300-L bioreactor (Fan et al 2022 ). However, there are few reports of titer enhancement of ilamycins E 1 /E 2 by fermentative process parameters optimization in wild-type strains and their mutants, especially.…”

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 .…”

“…atratus SCSIO ZH16, nonribosomal peptides ilamycins, especially ilamycin E, show brilliant anti-tuberculosis properties [ 9 ], and require yield improvement for the realization of industrial production or process. 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 ].…”

Recent progress of atmospheric and room‐temperature plasma as a new and promising mutagenesis technology

“…As biosynthesis has become increasingly popular, traditional methods usually have the problems of difficult process, complex by‐products, low yield, and shortage of supply. In response, a number of efforts have been made, such as media optimization, 131 metabolic pathway modification, 132 and traditional breeding methods 133 . However, these methods and techniques are still limited and inefficient in obtaining the desired phenotype.…”