Biotransformation of mestanolone and 17-methyl-1-testosterone byRhizopus stolonifer

Enhancing the biotransformation of progesterone to the anticancer compound testololactone by Penicillium chrysogenum Ras3009: kinetic modelling and efficiency maximization

BACKGROUND

Biotransformation of steroid compounds into therapeutic products using microorganisms offers an eco-friendly and economically sustainable approach to the pharmaceutical industry rather than a chemical synthesis way. The biotransformation efficiency of progesterone into the anticancer compound testololactone using Penicillium chrysogenum Ras3009 has been investigated. Besides, maximization of testololactone formation was achieved by studying the kinetic modelling and impact of some fermentation conditions on the biotransformation process.

RESULTS

The fungal strain Ras3009 was selected among twelve fungal strains as the most runner for the transformation of 81.18% of progesterone into testololactone. Ras3009 was identified phenotypically and genotypically as Penicillium chrysogenum, its 18 S rRNA nucleotide sequence was deposited in the GenBank database by the accession number OR480104. Studying the impact of fermentation conditions on biotransformation efficiency indicated a positive correlation between substrate concentration and testololactone formation until reaching the maximum velocity vmax. Kinetic studies revealed that vmax was [Formula: see text] gL- 1hr- 1 with high accuracy, giving R2 of 0.977. The progesterone transformation efficiency generally increased with time, reaching a maximum of 100% at 42 h with testololactone yield (Ypt/s) 0.8700 mg/mg. Moreover, the study indicated that the enzymatic conversion by P. chrysogenum Ras3009 showed high affinity to the substrate, intracellularly expressed, and released during cell disruption, leading to higher efficiency when using whole microbial cell extract.

CONCLUSIONS

Fungi can be promising biocatalysts for steroid transformation into valuable chemicals and pharmaceutical compounds. The study revealed that the new fungal isolate P. chrysogenum Ras3009 possesses a great catalytic ability to convert progesterone into testololactone. Kinetic modelling analysis and optimization of the fermentation conditions lead to higher transformation efficiency and provide a better understanding of the transformation processes.

Biotransformation of androst-4-ene-3,17-dione by three fungal species Fusarium solani BH1031, Aspergillus awamori MH18 and Mucor circinelloides W12

The microbial transformation of androst-4-ene-3,17-dione (4-AD; I) by three fungal species, involved Fusarium solani BH1031, Aspergillus awamori MH18 and Mucor circinelloides W12, has been studied. The latter two fungi were studied for the first time on biotransformation of 4-AD. The main product obtained by Fusarium solani BH1031 was 17α-oxa-D-homo-androst-1,4-diene-3,17-dione (testolactone; IV), which can be used as an anticancer agent. The main derivative yielded by Aspergillus awamori MH18 was 11α-hydroxyandrost-4-ene-3,17-dione (11α-OH-4-AD; VI), which was an important intermediate to produce Eplerenone. Meanwhile, the microbial transformation of 4-AD by Mucor circinelloides W12 produced three derivatives. Possible metabolic pathway of 4-AD via Fusarium solani BH1031 was proposed. Furthermore, the optimization for the production of 11α-OH-4-AD was carried out and the conversion rate reached to 84.0%. In this process, the dextrin and corn flour showed significant effects by response surface analysis.

Microbial transformation of mestanolone byMacrophomina phaseolinaandCunninghamella blakesleeanaand anticancer activities of the transformed products

The microbial transformation of anabolic androgenic steroid mestanolone (1) with Macrophomina phaseolina and Cunninghamella blakesleeana has afforded seven metabolites. The structures of these metabolites were characterized as 17β-hydroxy-17α-methyl-5α-androsta-1-ene-3,11-dione (2), 14α,17β-dihydroxy-17α-methyl-5α-androstan-3,11-dione (3), 17β-hydroxy-17α-methyl-5α-androstan-1,14-diene-3,11-dione (4), 17β-hydroxy-17α-methyl-5α-androstan-3,11-dione (5), 11β,17β-dihydroxy-17α-methyl-5α-androstan-1-ene-3-one (6), 9α,11β,17β-trihydroxy-17α-methyl-5α-androstan-3-one (7), and 1β,11α,17β-trihydroxy-17α-methyl-5α-androstan-3-one (8). All the metabolites, except 5 and 6, were identified as new compounds. Substrate 1 (IC₅₀ = 27.6 ± 1.1 μM), and its metabolites 2 (IC₅₀ = 19.2 ± 2.9 μM) and 6 (IC₅₀ = 12.8 ± 0.6 μM) exhibited moderate cytotoxicity against the HeLa cancer cell line (human cervical carcinoma). All metabolites were noncytotoxic to 3T3 (mouse fibroblast) and H460 (human lung carcinoma) cell lines. The metabolites were also evaluated for immunomodulatory activity, and all were found to be inactive.

The microbial transformation of anabolic androgenic steroid mestanolone (1) with Macrophomina phaseolina and Cunninghamella blakesleeana has afforded seven metabolites. Some of them have exhibited moderate cytotoxicity against HeLa cancer cell line.