Polyamines Upregulate Cephalosporin C Production and Expression of β-Lactam Biosynthetic Genes in High-Yielding Acremonium chrysogenum Strain

The high-yielding production of pharmaceutically significant secondary metabolites in filamentous fungi is obtained by random mutagenesis; such changes may be associated with shifts in the metabolism of polyamines. We have previously shown that, in the Acremonium chrysogenum cephalosporin C high-yielding strain (HY), the content of endogenous polyamines increased by four- to five-fold. Other studies have shown that the addition of exogenous polyamines can increase the production of target secondary metabolites in highly active fungal producers, in particular, increase the biosynthesis of β-lactams in the Penicillium chrysogenum Wis 54–1255 strain, an improved producer of penicillin G. In the current study, we demonstrate that the introduction of exogenous polyamines, such as spermidine or 1,3-diaminopropane, to A. chrysogenum wild-type (WT) and HY strains, leads to an increase in colony germination and morphological changes in a complete agar medium. The addition of 5 mM polyamines during fermentation increases the production of cephalosporin C in the A. chrysogenum HY strain by 15–20% and upregulates genes belonging to the beta-lactam biosynthetic cluster. The data obtained indicate the intersection of the metabolisms of polyamines and beta-lactams in A. chrysogenum and are important for the construction of improved producers of secondary metabolites in filamentous fungi.

Modelling, optimization and control of continuous two-stage Cephalosporin C production

Cephalosporin is one of the most consumed antibiotics for its effectiveness against a wide variety of infections. Most cephalosporin products are the semi-derivatives of Cephalosporin C (CPC), a metabolite of the fungus Acremonium chrysogenum. Since naturally the desired metabolite is not produced in a large amount by the fungus, an innovative operational strategy is required to increase its yield for the production of the antibiotic to be economically feasible. One way to increase the cephalosporin productivity is by increasing the concentration of thin hyphae cell in the bioreactor, but this will lead to a higher blower power requirement for providing adequate availability of oxygen in the fermentation broth. Lack of oxygen will retard the growth rate and reduce the productivity. Conversely, excessive aeration of the fermentation broth will lead to high shear stress that can kill the cells. The present work investigates through dynamic simulation the effectiveness of a continuous two-stage aerobic fermentation for the CPC production. The operating conditions are optimized to determine an optimal trade-off between the cephalosporin productivity and blower power. An increase of the dissolved oxygen in the first bioreactor from 10 % to 20 % can increase CPC productivity by 75.5 % from 24.42 mg/L.hr to 42.86 mg/L.hr.

PENINGKATAN PRODUKSI SEFALOSPORIN C DARI Acremonium chrysogenum CB2/11/1.10.6 DENGAN OPTIMASI MEDIA MENGGUNAKAN METODE RESPON PERMUKAAN

Cephalosporin is a β-lactam antibiotic produced by Acremonium chrysogenum using submerged fermentation. Carbon and nitrogen are the most influential medium ingredients for cephalosporin formation. The purpose of this study was to obtain the best composition of media for cephalosporin C production. Response surface methodology was used for production optimization. The results showed that molasses of 70 g/Lwas the best carbon source, while the best nitrogen source was the combination of corn steep liquor, urea and ammonium sulphate. DL-methionine, carbon, and nitrogen source significantly affected the production of cephalosporin C. The mathematically modelled optimization showed that the highest production of cephalosporin C (3876 mg/L) was obtained using medium composition of 68.28 g/L molasses, 71.61 g/L nitrogen, and 0.4 g/L DL-methionine. Laboratory verification using the same medium composition produced 3696 mg/L of cephalosporin C, being 4.65% different from the mathematically optimized results. Medium optimization increased the cephalosprin C production which was 1.48 times higher than that using the previous medium, where the maximum production was only 2487 mg / L.Keywords: Carbon, cephalosporin C, cultivation medium, nitrogen, A. chrysogenum ABSTRAKSefalosporin C adalah golongan antibiotik β-lactam yang dihasilkan Acremonium chrysogenum melalui fermentasi cair. Komponen yang sangat berpengaruh terhadap produksi sefalosporin C adalah sumber karbon dan nitrogen. Penelitian ini bertujuan mendapatkan komposisi media terbaik untuk produksi sefalosporin C. Optimasi dilakukan menggunakan metode respon permukaan. Hasil menunjukkan bahwa molases 70 g/L adalah sumber karbon terbaik dan kombinasi corn steep liquor, urea dan ammonium sulfat adalah sumber nitrogen terbaik. DL-methionin, sumber karbon, dan nitrogen berpengaruh nyata terhadap produksi sefalosporin C. Optimasi menggunakan model matematika menunjukkan produksi sefalosporin C tertinggi (3876 mg/L) yang diperoleh dengan komposisi media 68,28 g/L molases, 71,61 g/L nitrogen, dan 0,4 g/L DL-methionin. Verfikasi di laboratorium menggunakan komposisi media yang sama menghasilkan sefalosporin C sebesar 3696 mg/L, berbeda 4,65% dibanding dengan hasil optimasi matematis. Optimasi media mampu meningkatkan produksi sefalosprin C sebesar 1,48 kali dibanding media yang digunakan sebelumnya, dimana maksimal hanya menghasilkan 2487 mg/L.Kata kunci: Karbon, sefalosporin C, media kultivasi, nitrogen, A. chrysogenum