Cascade biotransformation of dehydroepiandrosterone (DHEA) by Beauveria species

Abstract

Beauveria bassiana is an entomopathogenic fungus used as a biological control agent. It is a well-known biocatalyst for the transformation of steroid compounds. Hydroxylations at the 7α or 11α position and oxidation to D-homo lactones are described in the literature. In our study, we examined the diversity of metabolism of five different B. bassiana strains and compared them to already known pathways. According to the literature, 7α and 11α-hydroxy derivatives as well as 3β,11α-dihydroxy-17a-oxa-D-homo-androst-5-en-17-one have been observed. Here we describe new DHEA metabolic pathways and two products not described before: 3β-hydroxy-17a-oxa-D-homo-androst-5-en-7,17-dione and 3β,11α-dihydroxyandrost-5-en-7,17-dione. We also used for the first time another species from this genus, Beauveria caledonica, for steroid transformation. DHEA was hydroxylated at the 7α, 7β and 11α positions and then reactions of oxidation and reduction leading to 3β,11α-dihydroxyandrost-5-en-7,17-dione were observed. All tested strains from the Beauveria genus effectively transformed the steroid substrate using several different enzymes, resulting in cascade transformation.

Biotransformation of Methoxyflavones by Selected Entomopathogenic Filamentous Fungi

“…bassiana species are the most common among the entomopathogenic filamentous fungi used in biotransformations, including in the case of flavonoid compounds [ 25 , 26 , 27 ]. In our previous studies concerning the biotransformation of steroids we have observed significant differences in the modification of dehydroepiandrosterone (DHEA) in the cultures of five different strains of this species [ 21 ]. Therefore, in this study, we decided to determine whether flavonoid compounds will also undergo diverse changes in the cultures of different strains of B. bassiana .…”

“…The presence and number of glycosyl substituents in the flavonoid molecule, depending on their position, should exhibit different, although not necessarily positive, properties. Naturally glycosylated derivatives of flavonoids occur widely in the world of plants, but their concentration in cells very often is relatively low [ 21 ], which makes their extraction difficult. New methods of obtaining glycosylated compounds on a larger scale are still necessary.…”

“…The biotransformation of five methoxyflavones with substituents on the B ring is described: 2′-( 1 ), 3′-( 2 ), 4′-( 3 )-methoxyflavones, 2′,5′-dimethoxyflavone( 4 ) and 3′,4′,5′-trimethoxyflavone( 5 ). Listed compounds were biotransformed by the strains of entomopathogenic filamentous fungi belonging to the species Beauveria bassiana KCh J1.5, J2.1, J3.2, J1, BBT, Beauveria caledonica KCh J3.3, J3.4 [ 21 ], Isaria fumosorosea KCh J2 [ 22 ] and Isaria farinosa KCh KW 1.1 [ 21 ]. Fungi of these species are among the most used for biotransformation, along with Aspergillus niger .…”

Distinct Regioselectivity of Fungal P450 Enzymes for Steroidal Hydroxylation

“…Hydroxylation at C-7 produces very useful hydroxysteroids of pharmacological value (32,33). Although many fungi have been reported to mediate 7-hydroxylation of steroids (34)(35)(36)(37)(38)(39)(40)(41)(42), low stereoselectivity (7␣/7␤) (38,41) and side hydroxylation reactions (37,42) have often been observed, thus presenting great challenges in developing highly regio-and stereoselective 7-hydroxylation processes of steroidal compounds. CYP5150AP3 favors the 7␤-hydroxylation of 11-deoxycortisol, a 3-keto-4-en-C 21 steroid, and may serve as a starting point for addressing these challenges.…”

Microbial Modifications of Androstane and Androstene Steroids by Penicillium vinaceum

“…Such an idea of configurational flexibility of steroid substrates was proposed already in 1967 on the basis of diverse metabolic fates of steroids biotransformed by Aspergillus tamarii cultures [ 28 ]. Some recent examples of the presence of steroidal BVMOs in fungal biotransformation pathways are: lactonization of progesterone and 5-ene steroids [ 29 , 30 ]; lactonization of dehydroepiandrosterone (DHEA), pregnenolone, and androstenedione by filamentous fungi of genus Penicillium [ 31 , 32 ]; lactonization of DHEA by Aspergillus parasiticus [ 33 ]; ring- d lactonization of steroidal C-17 ketones to 11α-hydroxy derivatives by Beauveria bassiana [ 34 ]; activity of Penicillium lanosocoeruleum in ring- d lactonization of C 19 -steroids [ 35 ] and pregnene-based steroids [ 36 ]; biotransformation of DHEA into hydroxylated steroid lactones Spicaria fumoso-rosea [ 37 ]; diverse biotransformation routes of steroids, including ring- d lactonization, in the cultures of Penicillium notatum [ 24 ] and Aspergillus terreus [ 38 ]; formation of testololactone from diverse steroidal substrates with the use of a multifunctional strain of Penicillium simplicissimum [ 39 ]; cascade of DHEA biotransformations by Beauveria species [ 40 ]; and the formation of new derivatives of 3β-acetyloxy-5α-chloro-6,19-oxidoandrostan-17-one [ 41 ]. This rich background of BVMO activity studies in fungal species, combined with the outlined above need for further research in the field of biotransformations, prompted us to investigate in detail metabolic fates of DHEA ( 1 ), epiandrosterone ( 2 ), androsterone ( 3 ), androstenedione ( 4 ), 19-OH-androstenedione ( 5 ), testosterone ( 6 ), 19-nortestosterone ( 7 ), progesterone ( 8 ), and pregnenolone ( 9 ) in the cultures of Penicillium vinaceum AM110.…”