Biotransformation of Progesterone by Penicillium aurantiogriseum

Microbial transformation of progesterone and dydrogesterone by bacteria from swine wastewater: Degradation kinetics and products identification

Natural and synthetic progestogens in livestock environments have become a concern due to the frequent presence and potential adverse effects on aquatic organisms. Here we investigated the biotransformation of progestogens by wastewater-borne bacteria in the field and laboratory under oxic and anoxic conditions. The results showed that all progestogens dissipated faster under oxic conditions than under anoxic conditions, and natural progesterone transformed faster than synthetic progestogens. Meanwhile, dozens of bacterial strains capable of degrading progestogens were successfully isolated from the swine wastewater, and Bacillus sp. P19 and Bacillus sp. DGT2 were found the best for progesterone and dydrogesterone transformation, respectively. In the degradation experiments using a single bacterial strain, progesterone and dydrogesterone dissipated under oxic conditions with half-lives of 11.6 h and 18.2 h, respectively. The transformation pathways were proposed based on the identified transformation products. The findings from this study showed that progestogens can be biotransformed, but not fully mineralized in the environment.

Biotransformation of androstenedione and androstadienedione by selected Ascomycota and Zygomycota fungal strains

Filamentous fungi is a huge phylum of lower eukaryotes with diverse activities towards various substrates, however, their biocatalytic potential towards steroids remains greatly underestimated. In this study, more than forty Ascomycota and Zygomycota fungal strains of 23 different genera were screened for the ability to catalyze structural modifications of 3-oxo-androstane steroids, - androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD). Previously unexplored for these purposes strains of Absidia, Acremonium, Beauveria, Cunninghamella, Doratomyces, Drechslera, Fusarium, Gibberella genera were revealed capable of producing in a good yield valuable 7α-, 7β-, 11α- and 14α-hydroxylated derivatives, as well as 17β-reduced and 1(2)-dehydrogenated androstanes. The bioconversion routes of AD and ADD were proposed based on the key intermediates identification and time courses of the bioprocesses. Six ascomycete strains were discovered to provide effective 7β-hydroxylation of ADD which has not been so far reported. The structures of major products and intermediates were confirmed by HPLC, mass-spectrometry (MS), ¹H and ¹³C NMR analyses. The results contribute to the knowledge on the functional diversity of steroid-transforming filamentous fungi. Previously unexplored fungal biocatalysts capable of effective performing structural modification of AD and ADD can be applied for industrial bioprocesses of new generation.

Biotransformation of progesterone and norgestrel by two freshwater microalgae (Scenedesmus obliquus and Chlorella pyrenoidosa): transformation kinetics and products identification

Natural and synthetic steroid hormones such as progesterone and norgestrel in the aquatic environment may cause adverse effects on aquatic organisms. This study investigated the biotransformation of progesterone and norgestrel in aqueous solutions by two freshwater microalgae Scenedesmus obliquus and Chlorella pyrenoidosa and elucidated their transformation mechanisms. More than 95% of progesterone was transformed by the two microalgae within 5d. For norgestrel, almost complete transformation by S. obliquus was observed after 5 d, but nearly 40% was remained when incubated with C. pyrenoidosa. The results also showed that these two compounds were not accumulated in the algal cells. Biotransformation was found to be the main mechanism for their loss in the aqueous solutions, and it followed the first-order kinetic model. For progesterone, three main transformation products, i.e. 3β-hydroxy-5α-pregnan-20-one, 3,20-allopregnanedione and 1,4-pregnadiene-3,20-dione, and six minor androgens were identified. For norgestrel, only two transformation products, 4,5-dihydronorgestrel and 6,7-dehydronorgestrel, were identified for the first time. Hydroxylation, reduction and oxidation are proposed to be the main transformation pathways. Among the two microalgae species, S. obliquus was found more efficient in the transformation of the two target compounds than C. pyrenoidosa. The results clearly demonstrated the capability of the two microalgae to transform the two progestogens. The biotransformation and products could have significant environmental implications in the fate and effects of the two steroids.

Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake

Fate and removal of 16 steroidal (estrogenic, androgenic and progestogenic) hormones were studied during advanced anaerobic digestion of sludge cake using microwave (MW) pretreatment. Effect of pretreatment temperature (80, 120, 160 °C), operating temperature (mesophilic at 35 ± 2 °C, thermophilic at 55 ± 2 °C) and sludge retention time (SRT: 20, 10, 5 days) were studied employing eight lab-scale semi-continuously fed digesters. To determine the potential effect of MW hydrolysis, hormones were quantified in total (sorbed + soluble) and supernatant (soluble) phases of the digester influent and effluent streams. Seven of 16 hormones were above the method reporting limit (RL) in one or more of the samples. Hormone concentrations in total phase of un-pretreated (control) and pretreated digester feeds ranged in <157-2491 ng/L and <157-749 ng/L, respectively. The three studied factors were found to be statistically significant (95% confidence level) in removal of one or more hormones from soluble and/or total phase. MW hydrolysis of the influent resulted in both release (from sludge matrix) and attenuation of hormones in the soluble phase. Accumulation of estrone (E1) as well as progesterone (Pr) and androstenedione (Ad) in most of the digesters indicated possible microbial transformations among the hormones. Compared to controls, all pretreated digesters had lower total hormone concentrations in their influent streams. At 20 days SRT, highest total removal (E1+E2+Ad +Pr) was observed for the thermophilic control digester (56%), followed by pretreated mesophilic digesters at 120 °C and 160 °C with around 48% efficiency. In terms of conventional performance parameters, relative (to control) improvements of MW pretreated digesters at a 5-d SRT ranged in 98-163% and 57-121%, for volatile solids removal and methane production, respectively.