Biotransformation of 6-dehydroprogesterone with Aspergillus niger and Gibberella fujikuroi

Characteristics of microbial community in EGSB system treating with oxytetracycline production wastewater

In order to realize the efficient and stable operation of anaerobic digestion for oxytetracycline (OTC) production wastewater which contains high concentration refractory organic matters and antibiotic residues, two laboratory-scale EGSB reactors (the experimental reactor and the control reactor) were constructed for pre-treating OTC production wastewater and the complex characteristics and connections among anaerobic fermentative bacteria, methanogens and fungi were analyzed. The experimental reactor gradually increased OTC doses of 0-200 mg/L by four phases compared with the control reactor which was fed without OTC addition during 280 days' operation. The average COD removal efficiency of 91.44% with the average OTC removal efficiency of 27.90% was achieved at OTC concentration of 200 mg/L. The addition of OTC did not affect the preponderant methanogen type, and Methanosaeta, a strict aceticlastic methanogen genus, was dominant both in working and controlling reactors on day 280. Redundancy analysis revealed that OTC and VFAs were the main environmental factors affecting the microbial communities and molecular ecological networks analysis indicated that the key genera principally belonged to Methanosaeta, Proteobacteria and Apiotrichum. Additionally, the fungi genus Apiotrichum might be related to the degradation of complex organic contaminants in OTC production wastewater treatment system.

Endophytic Fungi-Mediated Biocatalysis and Biotransformations Paving the Way Toward Green Chemistry

Catalysis is a process carried out in the presence of a heterogenous catalyst for accelerating the rate of a chemical reaction. It plays a pivotal role in transition from take, make, and dispose technology to sustainable technology via chemo- and biocatalytic processes. However, chemocatalyzed reactions are usually associated with copious amounts of perilous/hazardous environmental footprints. Therefore, whole-cell biotransformations or enzyme cocktails serve as cleaner biocatalytic alternatives in replacing the classical chemical procedures. These benchmark bioconversion reactions serve as important key technology in achieving the goals of green chemistry by eliminating waste generation at source. For this, nature has always been a driving force in fuelling natural product discovery and related applications. The fungal endophytic community, in particular, has undergone co-evolution with their host plant and has emerged as a powerful tool of genetic diversity. They can serve as a treasure trove of biocatalysts, catalyzing organic transformations of a wide range of substances into enantiopure compounds with biotechnological relevance. Additionally, the biocatalytic potential of endophytic fungi as whole-intact organisms/isolated enzyme systems has been greatly expanded beyond the existing boundaries with the advancement in high-throughput screening, molecular biology techniques, metabolic engineering, and protein engineering. Therefore, the present review illustrates the promising applications of endophytic fungi as biocatalysts for the synthesis of new structural analogs and pharmaceutical intermediates and refinement of existing proteins for novel chemistries.

Biotransformation of contraceptive drug desogestrel with Cunninghamella elegans, and anti-inflammatory activity of its metabolites

Biotransformation of an orally active contraceptive drug, desogestrel (1), with Cunninghamella elegans yielded a new metabolite, 13β-ethyl-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-17β-ol-3,6-dione (2), along with five known metabolites, i.e., 13β-ethyl-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3β,6β,17β-triol (3), 13β-ethyl-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-6β,17β-diol-3-one (4), 13β-ethyl-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-17β-ol-3-one (5), 13β-ethyl-11-epoxy-18,19-dinor-17α-pregn-4-en-20-yn-17β-ol-3-one (6), and 13β-ethyl-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-10β,17β-diol-3-one (7). The structure of new metabolite 2 was elucidated by using ¹H-, ¹³C-, and 2D-NMR, EI-, and HREI-MS, IR, and UV spectroscopic data. Compounds 1-7 were evaluated for anti-inflammatory activities, i.e., inhibition of T-cell proliferation, and pro-inflammatory cytokine (TNF-α). Compounds 1 (IC₅₀ = 1.12 ± 0.03 µg/mL), 2 (IC₅₀ = 1.15 ± 0.05 µg/mL), 3 (IC₅₀ = 1.15 ± 0.05 µg/mL), 4 (IC₅₀ = 1.40 ± 0.03 µg/mL), 5 (IC₅₀ = 1.78 ± 0.08 µg/mL), and 6 (IC₅₀ = 1.36 ± 0.07 µg/mL) were identified as potent inhibitors of T-cells proliferation, in comparison to the standard drug, prednisolone (IC₅₀ = 3.51 ± 0.03 µg/mL). Compound 7 (IC₅₀ = 6.18 ± 0.04 µg/mL) showed a good activity. In addition, substrate 1 (IC₅₀ ≤ 1 µg/mL), and its metabolites 2 (IC₅₀ = 4.1 ± 0.60 µg/mL), and 6 (IC₅₀ = 6.8 ± 0.8 µg/mL) also showed a potent inhibition of pro-inflammatory cytokine (TNF-α) production, as compared to the standards drug, pentoxifilline (IC₅₀ = 94.8 ± 2.1 µg/mL). Whereas compounds 3 (IC₅₀ = 57.9 ± 7.6 µg/mL), and 5 (IC₅₀ = 27.2 ± 6.8 µg/mL) showed a moderate inhibition of TNF-α production, while compounds 4 and 7 showed no inhibition. Compounds 1-7 were found to be non-cytotoxic to 3T3 normal cell line (mouse fibroblast).

Whole-cell fungal-mediated structural transformation of anabolic drug metenolone acetate into potent anti-inflammatory metabolites

Seven new derivatives, 6α-hydroxy-1-methyl-3-oxo-5α-androst-1-en-17-yl acetate (2), 6α,17β-dihydroxy-1-methyl-3-oxo-5α-androst-1-en (3), 7β-hydroxy-1-methyl-3-oxo-5α-androst-1-en-17-yl acetate (4), 15β,20-dihydroxy-1-methyl-3-oxo-5α-androst-1-en-17-yl acetate (5), 15β-hydroxy-1-methyl-3-oxo-5α-androst-1-en-17-yl acetate (6), 12β,17β-dihydroxy-1-methyl-3-oxoandrosta-1,4-dien (11), and 7β,15β,17β-trihydroxy-1-methyl-3-oxo-5α-androst-1-en (14), along with six known metabolites, 17β-hydroxy-1-methyl-3-oxoandrosta-1,4-dien (7), 17β-hydroxy-1-methyl-3-oxo-5α-androst-1-en (8), 17β-hydroxy-1-methyl-3-oxo-5β-androst-1-en (9), 1-methyl-5β-androst-1-en-3,17-dione (10), 1-methyl-3-oxoandrosta-1,4-dien-3,17-dione (12), and 17β-hydroxy-1α-methyl-5α-androstan-3-one (13) of metenolone acetate (1), were synthesized through whole-cell biocatalysis with Rhizopus stolonifer, Aspergillus alliaceous, Fusarium lini, and Cunninghamella elegans. Atamestane (12), an aromatase inhibitor, was synthesized for the first time via F. lini-mediated transformation of 1 as the major product. Hydroxylation, dehydrogenation, and reduction were occurred during biocatalysis. Study indicated that F. lini was able to catalyze dehydrogenation reactions selectively. Structures of compounds 1-14 were determined through NMR, HRFAB-MS, and IR spectroscopic data. Compounds 1-14 were identified as non-cytotoxic against BJ human fibroblast cell line (ATCC CRL-2522). Metabolite 5 (81.0 ± 2.5%) showed a potent activity against TNF-α production, as compared to the substrate 1 (62.5 ± 4.4%). Metabolites 2 (73.4 ± 0.6%), 8 (69.7 ± 1.4%), 10 (73.2 ± 0.3%), 11 (60.1 ± 3.3%), and 12 (71.0 ± 7.2%), also showed a good inhibition of TNF-α production. Compounds 3 (IC50 = 4.4 ± 0.01 µg/mL), and 5 (IC50 = 10.2 ± 0.01 µg/mL) showed a significant activity against T-cell proliferation. Identification of selective inhibitors of TNF-α production, and T-cell proliferation is a step forward towards the development of anti-inflammatory drugs.

New 6,19-oxidoandrostan derivatives obtained by biotransformation in environmental filamentous fungi cultures

Background

Steroid compounds with a 6,19-oxirane bridge possess interesting biological activities including anticonvulsant and analgesic properties, bacteriostatic activity against Gram-positive bacteria and selective anti-glucocorticoid action, while lacking mineralocorticoid and progestagen activity.

Results

The study aimed to obtain new derivatives of 3β-acetyloxy-5α-chloro-6,19-oxidoandrostan-17-one by microbial transformation. Twelve filamentous fungal strains were used as catalysts, including entomopathogenic strains with specific activity in the transformation of steroid compounds. All selected strains were characterised by high biotransformation capacity for steroid compounds. However, high substrate conversions were obtained in the cultures of 8 strains: Beauveria bassiana KCh BBT, Beauveria caledonica KCh J3.4, Penicillium commune KCh W7, Penicillium chrysogenum KCh S4, Mucor hiemalis KCh W2, Fusarium acuminatum KCh S1, Trichoderma atroviride KCh TRW and Isaria farinosa KCh KW1.1. Based on gas chromatography (GC) and nuclear magnetic resonance (NMR) analyses, it was found that almost all strains hydrolysed the ester bond of the acetyl group. The strain M. hiemalis KCh W2 reduced the carbonyl group additionally. From the P. commune KCh W7 and P. chrysogenum KCh S4 strain cultures a product of D-ring Baeyer–Villiger oxidation was isolated, whereas from the culture of B. bassiana KCh BBT a product of hydroxylation at the 11α position and oxidation of the D ring was obtained. Three 11α-hydroxy derivatives were obtained in the culture of I. farinosa KCh KW1.1: 3β,11α-dihydroxy-5α-chloro-6,19-oxidoandrostan-17-one, 3β,11α,19-trihydroxy-5α-chloro-6,19-oxidoandrostan-17-one and 3β,11α-dihydroxy-5α-chloro-6,19-oxidoandrostan-17,19-dione. They are a result of consecutive reactions of hydrolysis of the acetyl group at C-3, 11α- hydroxylation, then hydroxylation at C-19 and its further oxidation to lactone.

Conclusions

As a result of the biotransformations, seven steroid derivatives, not previously described in the literature, were obtained: 3β-hydroxy-5α-chloro-6,19-oxidoandrostan-17-one, 3β,17α-dihydroxy-5α-chloro-6,19-oxidoandrostane, 3β-hydroxy-5α-chloro-17α-oxa-D-homo-6,19-oxidoandrostan-17-one, 3β,11α-dihydroxy-5α-chloro-17α-oxa-D-homo-6,19-oxidoandrostan-17-one and the three above–mentioned 11α-hydroxy derivatives. This study will allow a better understanding and characterisation of the catalytic abilities of individual microorganisms, which is crucial for more accurate planning of experiments and achieving more predictable results.

Microbial transformation of oral contraceptive ethisterone by Aspergillus niger and Cunninghamella blakesleeana

Ethisterone (17α-ethynyl-17β-hydroxyandrost-4-en-3-one) (1) is a synthetic steroidal estrogen. It is extensively used as an oral contraceptive. The current study involves the structural transformation of ethisterone (1) by Aspergillus niger, and Cunninghamella blakesleeana. Fermentation of 1 with C. blakesleeana afforded two new polar metabolites, 17α-ethynyl-6β,15β,17β-trihydroxyandrost-4-en-3-one, and 17α-ethynyl-7β,15β,17β-trihydroxyandrost-4-en-3-one, while transformation of ethisterone with A. niger yielded a new metabolite, 17α-ethynyl-6α,17β-dihydroxyandrost-4-en-3-one, along with a known metabolite, 17α-ethynyl-11α,17β-dihydroxyandrost-4-en-3-one. Modern spectroscopic techniques were used to characterize the structures of all transformed products.

Biotransformation of progestonic hormone dydrogesterone with Macrophomina phaseolina, and study of the effect of biotransformed products on phagocytes oxidative burst

Biotransformation of a synthetic progestonic hormone dydrogesterone (1), C₂₁H₂₈O₂, with a plant pathogenic fungus Macrophomina phaseolina yielded two new 2 and 3, and a known 4 metabolites. These analogues were identified as, 3β,11α-dihydroxy-5β,9β,10α-pregna-7-ene-6,20-dione (2), 15β-hydroxy-9β,10α-pregna-4,6-diene-3,20-dione (3), and 8α-hydroxy-9β,10α-pregna-4,6-diene-3,20-dione (4). Major structural changes were observed in metabolite 2. New metabolite 3 showed anti-inflammatory potential, and was found to be the potent inhibitor of intracellular reactive oxygen species (ROS) from whole blood phagocytes (IC₅₀ = 4.2 ± 0.3 μg/mL), as compared to standard drug Ibuprofen (IC₅₀ = 11.2 ± 1.9 μg/mL). The metabolites 2, 3, and 4 were found to be non-toxic to NIH-3T3 (CRL-1658) normal cell line. This indicated anti-inflammatory potential of resulting metabolites.

Microbial biotransformation of bioactive and clinically useful steroids and some salient features of steroids and biotransformation

Steroids are perhaps one of the most widely used group of drugs in present day. Beside the established utilization as immunosuppressive, anti-inflammatory, anti-rheumatic, progestational, diuretic, sedative, anabolic and contraceptive agents, recent applications of steroid compounds include the treatment of some forms of cancer, osteoporosis, HIV infections and treatment of declared AIDS. Steroids isolated are often available in minute amounts. So biotransformation of natural products provides a powerful means in solving supply problems in clinical trials and marketing of the drug for obtaining natural products in bulk amounts. If the structure is complex, it is often an impossible task to isolate enough of the natural products for clinical trials. The microbial biotransformation of steroids yielded several novel metabolites, exhibiting different activities. The metabolites produced from pregnenolone acetate by Cunning hamella elegans and Rhizopus stolonifer were screened against tyrosinase and cholinesterase showed significant inhibitory activities than the parent compound. Diosgenin and its transformed sarsasapogenin were screened for their acetyl cholinesterase and butyryl cholinesterase inhibitory activities. Sarsasapogenin was screened for phytotoxicity, and was found to be more active than the parent compound. Diosgenin, prednisone and their derivatives were screened for their anti-leishmanial activity. All derivatives were found to be more active than the parent compound. The biotransformation of steroids have been reviewed to a little extent. This review focuses on the biotransformation and functions of selected steroids, the classification, advantages and agents of enzymatic biotransformation and examines the potential role of new enzymatically transformed steroids and their derivatives in the chemoprevention and treatment of other diseases. tyrosinase and cholinesterase inhibitory activities, severe asthma, rheumatic disorders, renal disorders and diseases of inflammatory bowel, skin, gastrointestinal tract.

Biotransformation, spectroscopic investigation, crystal structure and electrostatic properties of 3,7α-dihydroxyestra-1,3,5(10)-trien-17-one monohydrate studied using transferred electron-density parameters

The biologically transformed product of estradiol valerate, namely 3,7α-dihydroxyestra-1,3,5(10)-trien-17-one monohydrate, C₁₈H₂₂O₃·H₂O, has been investigated using UV-Vis, IR, ¹H and ¹³C NMR spectroscopic techniques, as well as by mass spectrometric analysis. Its crystal structure was determined using single-crystal X-ray diffraction based on data collected at 100 K. The structure was refined using the independent atom model (IAM) and the transferred electron-density parameters from the ELMAM2 database. The structure is stabilized by a network of hydrogen bonds and van der Waals interactions. The topology of the hydrogen bonds has been analyzed by the Bader theory of `Atoms in Molecules' framework. The molecular electrostatic potential for the transferred multipolar atom model reveals an asymmetric character of the charge distribution across the molecule due to a substantial charge delocalization within the molecule. The molecular dipole moment was also calculated, which shows that the molecule has a strongly polar character.

Hydroxylative activity of Aspergillus niger towards androst-4-ene and androst-5-ene steroids

Aspergillus niger, one of fungal species most frequently used for experimental and industrial-scale biotransformations of various organic compounds, is generally known to transform steroids at 16β position. In this work, application of the strain A. niger KCH910 to bioconversion of dehydroepiandrosterone (DHEA), androstenediol and testosterone is described, with emphasis on the metabolic steps leading to the products. Evidence from this study indicated that incubated 5-ene steroids underwent bioconversion within two metabolic pathways: oxidation by the action of 3β-HSD (3β-hydroxysteroid dehydrogenase) to 4-ene steroids, and minor allylic hydroxylation to epimeric 7-alcohols. Further transformation of the 3-oxo-4-ene metabolites resulted in non-selective 16-hydroxylation. It is the first report on an A. niger strain able to introduce not only 16β- but also 16α-hydroxyl function into steroids.

Regio- and stereo-selective hydroxylations of ingenane diterpenoids by Mortierella ramanniana and Gibberella fujikuroi

The regio- and stereo-selective hydroxylations of two ingenane diterpenoids, 20-deoxyingenol (1) and 13-oxyingenol dodecanoat (2), by the filamentous fungi Mortierella ramanniana and Gibberella fujikuroi were investigated in the present study. Four undescribed metabolites (3-6) of substrate 1 and two undescribed metabolites (7 and 8) of substrate 2 were isolated. All the metabolites were identified as hydroxylated ingenane derivatives by extensive NMR and HR-ESI-MS data analyses. All the biotransformed compounds and the substrates were evaluated for their cytotoxicities against three human cancer cell lines, including human colon cancer Caco-2, breast cancer MCF-7, and adriamycin (ADM)-resistant MCF-7/ADM cell lines. All ingenane alcohols (1, and 3-6) displayed no significant cytotoxic activities. The substrate 13-oxyingenol dodecanoat (2) showed moderate cytotoxicity with IC₅₀ values being 35.59 ± 5.37 μmol·L^-1 (Caco-2), 24.04 ± 4.70 μmol·L^-1 (MCF-7), and 22.24 ± 5.19 μmol·L^-1 (MCF-7/ADM). However, metabolites 7 and 8 displayed no significant cytotoxicity. These results indicated that the hydroxylation at the C-13 aliphatic acid ester of substrate 2 can significantly reduce the cytotoxic activity.

Review on fate and mechanism of removal of pharmaceutical pollutants from wastewater using biological approach

Due to research advancement and discoveries in the field of medical science, maintains and provides better human health and safer life, which lead to high demand for production of pharmaceutical compounds with a concomitant increase in population. These pharmaceutical (biologically active) compounds were not fully metabolized by the body and excreted out in wastewater. This micro-pollutant remains unchanged during wastewater treatment plant operation and enters into the receiving environment via the discharge of treated water. Persistence of pharmaceutical compounds in both surface and ground waters becomes a major concern due to their potential eco-toxicity. Pharmaceuticals (emerging micro-pollutants) deteriorate the water quality and impart a toxic effect on living organisms. Therefore, from last two decades, plenty of studies were conducted on the occurrence, impact, and removal of pharmaceutical residues from the environment. This review provides an overview on the fate and removal of pharmaceutical compounds via biological treatment process.