Microbial transformation of sterols to C19-steroids by Rhodococcus equi

A wild-type strain of Rhodococcus equi, isolated from soil, degraded cholesterol, -sitosterol, stigmasterol and mixed sterois to androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD). A definite preference for a relatively simply structured cholesterol side chain was observed. Highest specific cholesterol side-chain cleavage was associated with active growth of the culture. Maximum yield of ADD was obtained when sodium acetate and cholesterol were incorporated together in the medium. Specific side-chain cleavage required the presence of 2,2-dipyridyl, an inhibitor of ring cleavage.S. Ahmad and B.N. Johri are with the Department of Microbiology, College of Basic Sciences and Humanities, G.B. Pant University of Agriculture and Technology, Pantriagar 263 145, Nainital, UP, India. P.K. Roy, A.W. Khan and S.K. Basu are at Fermentation Technology Division, Central Drug Research Institute, Lucknow, India.     

Microbial conversion of sterols

By preselection of microorganisms which preferentially attack the side chain of cholesterol we have been able to isolate a mutant of Corynebacterium spec. Chol 73 which forms 20-carboxy-pregna-1,4-dien-3-one (BNC) from cholesterol in nearly quantitative yields. The structure of this compound has been established by means of¹³C NMR-,¹H NMR and CD spectroscopy.Dedicated to Dr. Bruno Werdelmann     

Microbial physiology of sidechain degradation of sterols

Summary A large number of valuable starting materials for steroids synthesis (e.g. 4-androstene-3,17-dione, 1,4-androstadiene-3,17-dione, 9-hydroxy-4-androsten-17-one) have been produced by microbial transformation methods. This review helps to evaluate the microbial physiological interest of the widely used sterol sidechain degradation processes. Four inducible groups of the catabolic enzymes are involved in the sterol sidechain degradation pathway; the fatty acid -oxidation system, the -oxidase reaction, a methyl-crotonyl-CoA carboxylation system and the propionyl-CoA carboylase system.Altogether nine catabolic enzymes are involved in the -sitosterol sidechain degradation pathway. They work in 14 consecutive enzymatic steps. Summing up: three molecules of FADH₂, three molecules of propionyl-SCoA, three of NADH and one molecule of acetic acid are formed, while the sidechain of one mole of sitosterol is removed selectively. The metabolism of the propionates and the acetate yield 18 molecules of NADH and 7 molecules of FADH₂. Taking into consideration the whole process more than 80 molecules of ATP could be formed during the sitosterol sidechain degradation process.     

Microbial transformation of xanthohumol

Microbial transformation of xanthohumol using the culture broth of Pichia membranifaciens afforded three metabolites, (E)-2"-(2"'-hydroxyisopropyl)-dihydrofurano[2",3":4',3']-2', 4-dihydroxy-6'-methoxychalcone, (2S)-2"-(2"'-hydroxyisopropyl)-dihydrofurano[2",3":7,8]-4'-hydroxy-5-methoxyflavanone and (E)-2"-(2"'-hydroxyisopropyl)-dihydrofurano[2",3":2',3']-4'-hydroxy-5-methoxychalcone.     

Microbial transformation of cannabinoids

Summary We tested 163 strains of fungi and bacteria for their ability to (–)-¹-(3R, 4R)-tetrahydrocannabinol (= ¹-THC) in vivo. In the experiments 51 strains were found to be active and were further tested under varying conditions. The screening is described and the metabolites of ¹-THC obtained from the incubations are characterized by their two-dimensional thin-layer Rf values and the color of the azo dyes formed by reacting the cannabinoids with Fast Blue B Salt reagent on the thin-layer plates. Cell-free systems were prepared from four strains of fungi and tested for in vitro conversion of ¹-THC. In two of these systems conversion of ¹-THC to metabolites could be demonstrated.Part 1, see Binder (1976)     

Microbial transformation of steroids

При помощи ?ерменентации со 191 штаммом 94 видов рода Penicillium исследовались превращения прогестерона. Качественный анализ метаболитов при помощи хроматогра?ии на бумаге с различной детекцией при сравнении со стандартными образцами обнаружил З основных типа превращений, а именно, отщепление боковой цепи прогестерона на С₁₇ при образовании. с другой сторны, тестололактона, а с другой стороны, тестостерона в качечестве конечного метаболита и гидроксилирование лрогестерона в положении 11, а также в положении 15 стероидного скелета. У некоторых видов рода Penicillium была установлена неспособность превращать молекулу прогестерона в другое стероидное соединение. Отдельные виды Penicillium были разделены на 5 групп по способности их ?ерментных систем вызывать превращения стероидной молекулы прогестерона.     

Microbial transformation of mesterolone

The microbial transformation of mesterolone (= (1alpha,5alpha,17beta)-17-hydroxy-1-methylandrostan-3-one; 1), by a number of fungi yielded (1alpha,5alpha)-1-methylandrostane-3,17-dione (2), (1alpha,3beta,5alpha,17beta)-1-methylandrostane-3,17-diol (3), (5alpha)-1-methylandrost-1-ene-3,17-dione (4), (1alpha,5alpha,15alpha)-15-hydroxy-1-methylandrostane-3,17-dione (5), (1alpha,5alpha,6alpha,17beta)-6,17-dihydroxy-1-methylandrostan-3-one (6), (1alpha,5alpha,7alpha,17beta)-7,17-dihydroxy-1-methylandrostan-3-one (7), (1alpha,5alpha,11alpha,17beta)-11,17-dihydroxy-1-methylandrostan-3-one (8), (1alpha,5alpha,15alpha, 17beta)15,17-dihydroxy-1-methylandrostan-3-one (9), and (5alpha,15alpha,17beta)-15,17-dihydroxy-1-methylandrost-1-en-3-one (10). Metabolites 5-10 were found to be new compounds. All metabolites, except 2, 3, 6, and 7, exhibited potent anti-inflammatory activity. The structures of these metabolites were characterized on the basis of spectroscopic studies, and the structure of 5 was also determined by single-crystal X-ray-diffraction analysis.     

Microbial transformation of papaveraldine

Preparative-scale fermentation of papaveraldine (1), the known benzylisoquinoline alkaloid, with Mucor ramannianus 1839 (sih) has resulted in a stereoselective reduction of the ketone group and the isolation of S-papaverinol (2) and S-papaverinol N-oxide (3). The structure elucidation of both metabolites was based primarily on 1D-, 2D-NMR analyses and chemical transformations. The absolute configuration of 2 was determined using Horeau's method of asymmetric esterification. These metabolism results were consistent with the previous plant cell transformation studies on papaverine and isopapaverine.     

Microbial transformation of steroids

A systematic study of transformation reactions of Actinomycetes with respect to the progesterone molecule was undertaken. The results obtained, i.e. the types of transformation reactions in different actinomycete species, were evaluated from the point of view of taxonomy. The actinomycetes tested were divided according to the transformation types into three groups: (1) a group of species transforming progesterone in the 16α-position; (2) a group of species transforming progesterone in the β-position; (3) a group of species in which no capacity to transform progesterone into another steroid derivative was established. From the point of view of Actinomycete classification the transformation reactions on the steroid molecule fulfil all the requirements of taxonomic features of Actinomycetes. They appear to be specific properties, independent of strictly cultivation conditions and common to all the strains of individual actinomycete species tested.     

Microbial transformation of ethylpyridines

Pyridine and its derivatives have been found as pollutants in the environment. Although alkylpyridines constitute the largest class of pyridines contaminating the environment, little information is available concerning the fate and transformation of these compounds. In this investigation ethylpyridines have been used as model compounds for investigating the biodegradability of alkylpyridines. A mixed culture of ethylpyridine-degrading microorganisms was obtained from a soil that had been exposed to a variety of pyridine derivatives for several decades. The enrichment culture was able to degrade 2-, 3-, and 4-ethylpyridine (100 mg/L) at 28° C and pH 7 within two weeks under aerobic conditions. The degradation rate was greatest for 2-ethylpyridine and least for 3-ethylpyridine. Transformation of ethylpyridines was dependent on substrate concentration, pH, and incubation temperature. Studies on the metabolic pathway of 4-ethylpyridine revealed two products; these chemicals were identified by MS and NMR analyses as 4-ethyl-2(1H)-pyridone and 4-ethyl-2-piperidone. 6-Ethyl-2(1H)-pyridone was determined to be a product of 2-ethylpyridine degradation. These results indicate that the transformation mechanism of ethylpyridines involves hydroxylation and reduction of the aromatic ring before ring cleavage.     

Microbial transformation of zaluzanin-D

Microbial transformation of zaluzanin-D using different fungi gave 11,13-dihydrozaluzanin-C, zaluzanin-C, 4,16,11,13 - tetrahydro zaluzanin-C, estafiatone, dihydroestafiatol and dihydroestafiatone.     

Microbial transformation of steroid

When studying the transformation reactions of Δ⁴-3-ketosteroids of the pregnane series by strains ofStreptomyces fradiae, 6β-hydroxy-or 6β, 11α-dihydroxy-derivatives were found to be the main metabolites. From the aspect of the taxonomy of Actinomycetes, these reactions can be utilized in classification of the species, since study of different strains ofStreptomyces fradiae showed that this property is stable and that it is characteristic for the given species.     

Microbial transformation of alkaloids

Alkaloids continue to provide mankind with a plethora of medicines, poisons and potions. Because many valuable drugs are derived from such natural compounds, there is much interest in their transformation to provide new compounds or intermediates for the synthesis of new or improved drugs. This review aims to provide a survey of alkaloid transformations, and concerns microbial transformations and microbially expressed recombinant plant enzymes and their biotechnological applications.     

Microbial transformation of chlorinated benzoates

Chlorinated benzoates enter the environment through their use as herbicides or as metabolites of other halogenated compounds. Ample evidence is available indicating biodegradation of chlorinated benzoates to CO₂ and chloride in the environment under aerobic as well as anaerobic conditions. Under aerobic conditions, lower chlorinated benzoates can serve as sole electron and carbon sources supporting growth of a large list of taxonomically diverse bacterial strains. These bacteria utilize a variety of pathways ranging from those involving an initial degradative attack by dioxygenases to those initiated by hydrolytic dehalogenases. In addition to monochlorinated benzoates, several bacterial strains have been isolated that can grow on dichloro-, and trichloro- isomers of chlorobenzoates. Some aerobic bacteria are capable of cometabolizing chlorinated benzoates with simple primary substrates such as benzoate. Under anaerobic conditions, chlorinated benzoates are subject to reductive dechlorination when suitable electron-donating substrates are available. Several halorespiring bacteria are known which can use chlorobenzoates as electron acceptors to support growth. For example, Desulfomonile tiedjei catalyzes the reductive dechlorination of 3-chlorobenzoate to benzoate. The benzoate skeleton is mineralized by other microorganisms in the anaerobic environment. Various dichloro- and trichlorobenzoates are also known to be dechlorinated in anaerobic sediments.     

Microbial transformation of 3-desoxy-dihydromorphinanes

Summary 3-Desoxymorphinanes should be transformed by microbial hydroxylation of the aromatic ring to morphinanes. Instead of this reaction the investigated N-derivatives (H, CH₃, COCH₂OH and COCH₂OCH₂CH₃) are reduced by several fungi to the 6-(R)-hydroxy structures. Rhizopus achlamydosporus cleaved additionally the ethoxy-acetyl-group to a hydroxy-acetate.     

Microbial transformation of antimalarial terpenoids

The fungal and bacterial transformation of terpenoids derived from plant essential oils, especially the sesquiterpenoid artemisinin from Artemisia annua, has produced several new candidate drugs for the treatment of malaria. Obtaining new derivatives of terpenoids, including artemisinin derivatives with increased antimalarial activity, is an important goal of research in microbial biotechnology and medicinal chemistry.     

Microbial transformation of 2,4,6-trinitrotoluene

The manufacture and decommissioning of explosives has generated, and continues to generate, large quantities of waste material whose primary toxic and mutagenic component is 2,4,6-trinitrotoluene (TNT). The magnitude of this problem has motivated a great deal of research into treatment processes and environmental fate studies, including characterization of microbial transformations of TNT. This work has encompassed studies with mixed cultures and pure cultures of microorganisms derived from either TNT-exposed or unexposed sources, and studies using microorganisms chosen for their known capacities to degrade other pollutants. Several of these studies are discussed with regard to whether they identified a process that may lead to the complete detoxification or mineralization of TNT. Since oxygen can have a significant influence on the types of biochemical reactions that can occur and on the oxidation of intermediates of TNT transformation processes, studies in which oxygen was not excluded are discussed separately from studies conducted under anaerobic conditions. Received 31 October 1995/ Accepted in revised form 29 March 1996     

Microbial transformation of kepone.

Pseudomonas aeruginosa strain KO3 and a mixed aerobic enrichment culture, isolated from sewage sludge lagoon water, were found to aerobically transform the chlorinated insecticide Kepone, yielding monohydro-Kepone. Identification of the product was confirmed by gas chromatography and electron impact mass spectrometry. The mixed culture and P. aeruginosa strain KO3 produced about 4 and 16%, respectively, dihydro-Kepone, determined by cochromatography using authentic standards. Reduced amounts of monohydro-Kepone, compared with the mixed and pure cultures, were produced by James River sediment microorganisms. Kepone was not utilized as a sole carbon or energy source by any of the bacteria or mixed cultures examined in this study.     

Microbial transformation of baicalin and baicalein

As a result of microbial transformation of baicalin and baicalein the products of 4′-hydroxylation of the B ring, O-methylation at C-6, and both O-methylation at C-6 and hydroxylation at C-4′ were obtained. Transformations of baicalin were accompanied by the reaction of hydrolysis.