Search Results (94)

Bioconversion of cortisone leads to the synthesis of the steroid derivatives 1,9β,17,21-tetrahydroxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11,20-dione (SCA) and 1,9β,17,20β,21-pentahydroxy-4-methyl-19-nor-9β-pregna-1,3,5(10)-trien-11-one (SCB), which have been identified as biologically active molecules in affections associated with oxidative stress and inflammation, particularly in the skin and eye. To date, the synthesis of SCA and SCB can only be achieved through a biocatalytic approach, following a biotransformation process catalyzed by Rhodococcus rhodnii DSM 43960, a synthetic pathway that adheres to the principles of green chemistry. To further enhance the sustainability of this process, this study demonstrated that SCA and SCB can be synthesized by bioconversion in a complex medium derived from a dual upcycling process involving olive leaves (UOLM). By formulating a medium based on olive leaves, a by-product derived from the previously reported biotechnological production of lactic acid, and using a concentration of 10% v/v UOLM and 1 g/L cortisone at pH 7.5, bioconversion yields of 90 ± 4.5% were achieved, with a predominance of SCB. Investigations into the addition of supplements, such as tryptone, peptone, and corn steep liquor (CSL), to assess potential improvements in yield were conducted, but no significant positive variations were observed. For the first time, bioactive steroids were synthesized from a medium obtained through a dual upcycling process of olive leaves, introducing an innovative method that opens new possibilities for the investigation of a second generation of biosteroids synthesized from lignocellulosic feedstocks. Full article

We first measured the content of chlorfenapyr and tralopyril in silkworm larvae using HPLC, revealing that chlorfenapyr can be biotransformed into tralopyril in silkworms. Then, a differential transcriptomic database of small RNA was constructed through Illumina RNA-Sequencing. qRT-PCR was conducted to determine the expression levels of Bmo-miR-6497-5p and the target CYP450 gene, and Bmo-miR-6497-5p was significantly upregulated in the L3 silkworm larvae 24, 48, and 72 h after they were treated with chlorfenapyr. Furthermore, the target P450 gene CYP337A2 was downregulated at these time points. Dual-luciferase validation revealed that the luciferase activity significantly decreased after Bmo-miR-6497-5p bound to CYP337A2. In addition, miRNA mimics/inhibitor injection and bioassays of chlorfenapyr and tralopyril revealed that the mortality of third silkworm larvae injected with the antagomir of Bmo-miR-6497-5p was significantly increased after exposure to a sublethal concentration of chlorfenapyr. These results imply that Bmo-miR-6497-5p targets CYP337A2, regulating its expression. Also, silkworms increase their tolerance to chlorfenapyr by upregulating Bmo-miR-6497-5p expression, thereby inhibiting the biotransformation of chlorfenapyr to toxic tralopyril catalyzed by CYP337A2. The present study reveals the function of microRNA in silkworm tolerance to chlorfenapyr and improves understanding regarding insecticide resistance in Lepidopteran insects. Full article

(R)-3-aminobutyric acid is an important raw material for dolutegravir production, which is a key antiretroviral medicine for AIDS treatment. Currently, the industrial production of (R)-3-aminobutyric acid relies on chiral resolution methods, which are plagued by high pollution and low yield efficiency. Here, we report an efficient pathway for (R)-3-aminobutyric acid production via engineered aspartase-driven biotransformation in recombinant E. coli. The engineered aspartase mutants, obtained through rational design based on catalytic mechanisms, were specifically employed to catalyze the production of (R)-3-aminobutyric acid from crotonic acid. The engineered T187L/N142R/N326L aspartase mutant exhibited the highest enzyme activity of 1516 U/mg. Through cell permeabilization, the system achieved (R)-3-aminobutyric acid yield of 287.6 g/L (96% productivity) within 24 h. Subsequent scale-up in a 7 L fermenter achieved a final product yield of 284 g/L (95% productivity) within 24 h. Economic balance showed that the cost of industrial production (¥116.21/kg) is about 1/4 of the laboratory production (¥479.76/kg). In summary, the engineered aspartase-mediated bioconversion pathway using recombinant E. coli offers an industrially viable approach for (R)-3-aminobutyric acid production, featuring mild reaction conditions, environmental sustainability, streamlined processing, high yield, and cost-effective substrates. Full article

Glycosylation is a critical enzymatic modification that involves the attachment of sugar moieties to target compounds, considerably influencing their physicochemical and biological characteristics. This review explored the role of two primary enzyme classes—glycosyltransferases (GTs) and glycoside hydrolases (GHs, glycosidases)—in catalyzing the glycosylation of natural products, with a specific focus on Ganoderma triterpenoids. While GTs typically use activated sugar donors, such as uridine diphosphate glucose, certain GHs can leverage more economical sugar sources, such as sucrose and starch, through transglycosylation. This paper also reviewed strategies for producing novel terpenoid glycosides, particularly recently isolated bacterial GTs and GHs capable of glycosylating terpenoids and flavonoids. It summarized the newly synthesized glycosides’ structures and biotransformation mechanisms, enhanced aqueous solubility, and potential applications. The regioselectivity and substrate specificity of GTs and GHs in catalyzing O-glycosylation (glucosylation) at distinct hydroxyl and carboxyl groups were compared. Furthermore, a special case in which the novel glycosylation reactions were mediated by GHs, including the formation of unique glycoside anomers, was included. The advantages and specific capabilities of GT/GH enzymes were evaluated for their potential in biotechnological applications and future research directions. Novel fungal triterpenoid glycosides produced through various glycosidases and sugars is expected to expand their potential applications in the future. Full article

Ustiloxins are a kind of cyclopeptide mycotoxins produced by rice false smut pathogen Villosiclava virens, which seriously threatens the safe production of rice and health of humans and animals. Hydroxylation, a biotransformation reaction that regio- and stereoselectively introduces a hydroxyl group into the molecule catalyzed by the hydroxylase produced by organisms, has been considered an efficient way to detoxify mycotoxins. In this study, the endophytic fungus Petriella setifera Nitaf10 was found to be able to detoxify ustiloxin A, the main toxic component in V. virens. In addition to the two main transformed products previously identified, ustiloxins A1 and A2, an additional transformed product was obtained by using cell-free extract (CFE) of P. setifera Nitaf10 prepared with 5 mmol/L of pH 9.0 carbonate-buffered solution (CBS). It was structurally characterized as a novel ustiloxin analog named 13-hydroxy ustiloxin A (1) by analysis of the 1D and 2D NMR and HRESIMS spectra as well as by comparison with known ustiloxins. Biotransformation reaction of ustiloxin A was found to proceed via hydroxylation, and was possibly catalyzed by the intracellular hydroxylase in the CFE. The cytotoxic and phytotoxic activities of 13-hydroxy ustiloxin A (1) were much weaker than those of ustiloxin A. Detoxification of ustiloxin A by hydroxylation of P. setifera will be an efficient strategy. Full article

The extensive use of pharmaceuticals in human and veterinary medicine has led to their persistent environmental release, posing ecological and public health risks. Major sources include manufacturing effluents, excretion, aquaculture, and improper disposal, contributing to bioaccumulation and ecotoxicity. Mycoremediation is the fungal-mediated biodegradation of pharmaceuticals, offers a promising and sustainable approach to mitigate pharmaceutical pollution. Studies have reported that certain fungal species, including Trametes versicolor and Pleurotus ostreatus, can degrade up to 90% of pharmaceutical contaminants, such as diclofenac, carbamazepine, and ibuprofen, within days to weeks, depending on environmental conditions. Fungi produce a range of extracellular enzymes, such as laccases and peroxidases, alongside intracellular enzymes like cytochrome P450 monooxygenases, which catalyze the transformation of complex pharmaceutical compounds. These enzymes play an essential role in modifying, detoxifying, and mineralizing xenobiotics, thereby reducing their environmental persistence and toxicity. The effectiveness of fungal biotransformation is influenced by factors such as substrate specificity, enzyme stability, and environmental conditions. Optimal degradation typically occurs at pH 4.5–6.0 and temperatures of 20–30 °C. Recent advancements in enzyme engineering, immobilization techniques, and bioreactor design have improved catalytic efficiency and process feasibility. However, scaling up fungal-based remediation systems for large-scale applications remains a challenge. Addressing these limitations with synthetic biology, metabolic engineering, and other biotechnological innovations could further enhance the enzymatic degradation of pharmaceuticals. This review highlights the enzymatic innovations, applications, and challenges of pharmaceutical mycoremediation, emphasizing the potential of fungi as a transformative solution for sustainable pharmaceutical waste management. Full article

Selenium (Se), a potentially toxic trace element, undergoes complex biogeochemical cycling in the environment, largely driven by microbial activity. The reduction in selenate or selenite to elemental selenium is an environmentally beneficial process, as it decreases both Se toxicity and mobility. This reduction is catalyzed by enzymes encoded by various related genes. The link between Se reduction gene clusters and specific taxonomic groups is significant for elucidating the ecological roles and processes of Se reduction in diverse environments. In this study, a new species of Se-reducing microorganism belonging to the genus Anaerobacillus was isolated from a mining site. A comparative analysis of the growth characteristics reveals that Anaerobacillus species exhibit notable metabolic versatility, particularly in their fermentation abilities and utilization of diverse electron donors and acceptors. Genome analysis identified a diverse array of gene clusters associated with selenate uptake (sul, pst), selenate reduction (ser), and selenite reduction (hig, frd, trx, and bsh). Since selenate reduction is the first crucial step in Se reduction, genes linked to selenate reductase are the focus. The serA gene clusters analysis suggests that the serA gene is highly conserved across Anaerobacillus species. The surrounding genes of serA show significant variability in both presence and gene size. This evolutionary difference in coenzyme utilization and serA regulation suggests distinct survival strategies among Anaerobacillus species. This study offers insights into Se bio-transformations and the adaptive strategies of Se-reducing microorganisms. Full article

Ustiloxins are a group of cyclopeptide mycotoxins produced by rice false smut pathogen Villosiclava virens (anamorph: Ustilaginoidea virens) which seriously threaten the safety production of rice and the health of humans and livestock. Ustiloxin A, accounting for 60% of the total ustiloxins, is the main toxic component. Biotransformation, a process of modifying the functional groups of compounds by means of regio- or stereo-specific reactions catalyzed by the enzymes produced by organisms, has been considered as an efficient way to detoxify mycotoxins. In this study, the endophytic fungus Petriella setifera Nitaf10 was found to be able to detoxify ustiloxin A through biotransformation. Two transformed products were obtained by using the cell-free extract (CFE) containing intracellular enzymes of P. setifera Nitaf10. They were structurally characterized as novel ustiloxin analogs named ustiloxins A1 (1) and A2 (2) by analysis of the 1D and 2D NMR and HRESIMS spectra as well as by comparison with known ustiloxins. The cytotoxic activity of ustiloxins A1 (1) and A2 (2) was much weaker than that of ustiloxin A. The biotransformation of ustiloxin A was found to proceed via oxidative deamination and decarboxylation and was possibly catalyzed by the intracellular amine oxidase and oxidative decarboxylase in the CFE. An appropriate bioconversion was achieved by incubating ustiloxin A with the CFE prepared in 0.5 mol/L phosphate buffer (pH 7.0) for 24 to 48 h. The optimum initial pH values for the bioconversion of ustiloxin A were 7–9. Among eight metal ions (Co²⁺, Cu²⁺, Fe³⁺, Zn²⁺, Ba²⁺, Ca²⁺, Mg²⁺ and Mn²⁺) tested at 5 mmol/L, Cu²⁺, Fe³⁺ and Zn²⁺ totally inhibited the conversion of ustiloxin A. In conclusion, detoxification of ustiloxin A through oxidative deamination and decarboxylation is an efficient strategy. Full article

The quest for novel therapeutic agents has rekindled interest in natural products, particularly those derived from biotransformation processes. Dihydrochalcones, a class of plant secondary metabolites, exhibit a range of pharmacological properties. Chalcone and dihydrochalcone compounds with the characteristic 4’-hydroxy substitution are present in ‘dragon’s blood’ resin, known for its traditional medicinal uses and complex composition, making the isolation of these compounds challenging. This study investigates the efficient production of 4′-hydroxydihydrochalcones using non-conventional yeast strains. We evaluated the biotransformation efficiency of various 4′-hydroxychalcone substrates utilizing yeast strains such as Yarrowia lipolytica KCh 71, Saccharomyces cerevisiae KCh 464, Rhodotorula rubra KCh 4 and KCh 82, and Rhodotorula glutinis KCh 242. Our findings revealed that Yarrowia lipolytica KCh 71, Rhodotorula rubra KCh 4 and KCh 82, and Rhodotorula glutinis KCh 242 exhibited the highest conversion efficiencies, exceeding 98% within one hour for most substrates. The position of methoxy substituents in the chalcone ring significantly influenced hydrogenation efficiency. Moreover, we observed isomerization of trans-4′-hydroxy-2-methoxychalcone to its cis isomer, catalyzed by light exposure. This study underscores the potential of using yeast strains for the sustainable and efficient production of dihydrochalcones, providing a foundation for developing new therapeutic agents and nutraceuticals. Full article

Xanthohumol (1) is a major prenylated flavonoid in hops (Humulus lupulus L.) which exhibits a broad spectrum of health-promoting and therapeutic activities, including anti-inflammatory, antioxidant, antimicrobial, and anticancer effects. However, due to its lipophilic nature, it is poorly soluble in water and barely absorbed from the gastrointestinal tract, which greatly limits its therapeutic potential. One method of increasing the solubility of active compounds is their conjugation to polar molecules, such as sugars. Sugar moiety introduced into the flavonoid molecule significantly increases polarity, which results in better water solubility and often leads to greater bioavailability. Entomopathogenic fungi are well known for their ability to catalyze O-glycosylation reactions. Therefore, we investigated the ability of selected entomopathogenic filamentous fungi to biotransform xanthohumol (1). As a result of the experiments, one aglycone (2) and five glycosides (3–7) were obtained. The obtained (2″E)-4″-hydroxyxanthohumol 4′-O-β-D-(4‴-O-methyl)-glucopyranoside (5) has never been described in the literature so far. Interestingly, in addition to the expected glycosylation reactions, the tested fungi also catalyzed chalcone–flavanone cyclization reactions, which demonstrates chalcone isomerase-like activity, an enzyme typically found in plants. All these findings undoubtedly indicate that entomopathogenic filamentous fungi are still an underexploited pool of novel enzymes. Full article

Cytochrome P450 enzymes (P450s) play a critical role in drug metabolism, with the CYP3A subfamily being responsible for the biotransformation of over 50% of marked drugs. While CYP3A enzymes are known for their extensive catalytic versatility, one intriguing and less understood function is the ability to mediate carbon–carbon (C–C) bond cleavage. These uncommon reactions can lead to unusual metabolites and potentially influence drug safety and efficacy. This review focuses on examining examples of C–C bond cleavage catalyzed by CYP3A, exploring the mechanisms, physiological significance, and implications for drug metabolism. Additionally, examples of CYP3A-mediated ring expansion via C–C bond cleavages are included in this review. This work will enhance our understanding of CYP3A-catalyzed C–C bond cleavages and their mechanisms by carefully examining and analyzing these case studies. It may also guide future research in drug metabolism and drug design, improving drug safety and efficacy in clinical practice. Full article

Salinispirillum sp. LH 10-3-1 was newly isolated from the alkali lake water samples collected in Inner Mongolia. In this study, a gene coding for D-lactate dehydrogenase from the strain LH 10-3-1 (SaLDH) was cloned and characterized. The recombinant enzyme was a tetramer with a native molecular mass of 146.2 kDa. The optimal conditions for SaLDH to reduce pyruvate and oxidize D-lactic acid were pH 8.0 and pH 5.0, at 25 °C. Cu²⁺ and Ca²⁺ slightly promoted the oxidation and reduction activities of SaLDH, respectively. To improve the stability of SaLDH, the enzyme was immobilized on Cu₃(PO₄)₂-based inorganic hybrid nanoflowers. The results showed that the reduction activity of the hybrid nanoflowers disappeared, and the optimum temperature, specific activity, thermostability, and storage stability of the immobilized SaLDH were significantly improved. In addition, the biotransformation of D-lactic acid to pyruvate catalyzed by SaLDH and the hybrid nanoflowers was investigated. The maximum conversion of D-lactic acid catalyzed by the immobilized SaLDH was 25.7% higher than by free enzymes, and the immobilized SaLDH could maintain 84% of its initial activity after six cycles. Full article

This study provides a comprehensive computational exploration of the inhibitory activity and metabolic pathways of 8-methoxypsoralen (8-MP), a furocoumarin derivative used for treating various skin disorders, on cytochrome P450 (P450). Employing quantum chemical DFT calculations, molecular docking, and molecular dynamics (MD) simulations analyses, the biotransformation mechanisms and the active site binding profile of 8-MP in CYP1B1 were investigated. Three plausible inactivation mechanisms were minutely scrutinized. Further analysis explored the formation of reactive metabolites in subsequent P450 metabolic processes, including covalent adduct formation through nucleophilic addition to the epoxide, 8-MP epoxide hydrolysis, and non-CYP-catalyzed epoxide ring opening. Special attention was paid to the catalytic effect of residue Phe268 on the mechanism-based inactivation (MBI) of P450 by 8-MP. Energetic profiles and facilitating conditions revealed a slight preference for the C4′=C5′ epoxidation pathway, while recognizing a potential kinetic competition with the 8-OMe demethylation pathway due to comparable energy demands. The formation of covalent adducts via nucleophilic addition, particularly by phenylalanine, and the generation of potentially harmful reactive metabolites through autocatalyzed ring cleavage are likely to contribute significantly to P450 metabolism of 8-MP. Our findings highlight the key role of Phe268 in retaining 8-MP within the active site of CYP1B1, thereby facilitating initial oxygen addition transition states. This research offers crucial molecular-level insights that may guide the early stages of drug discovery and risk assessment related to the use of 8-MP. Full article

The synthetic cytokinin forchlorfenuron (FCF), while seemingly presenting relatively low toxicity for mammalian organisms, has been the subject of renewed scrutiny in the past few years due to its increasing use in fruit crops and potential for bioaccumulation. Despite many toxicological properties of FCF being known, little research has been conducted on the toxicological effects of its secondary metabolites. Given this critical gap in the existing literature, understanding the formation of relevant FCF secondary metabolites and their association with mammalian metabolism is essential. To investigate the formation of FCF metabolites in sufficient quantities for toxicological studies, a panel of four fungi were screened for their ability to catalyze the biotransformation of FCF. Of the organisms screened, Cunninghamella elegans (ATCC 9245), a filamentous fungus, was found to convert FCF to 4-hydroxyphenyl-forchlorfenuron, the major FCF secondary metabolite identified in mammals, after 26 days. Following the optimization of biotransformation conditions using a solid support system, media screening, and inoculation with a solid pre-formed fungal mass of C. elegans, this conversion time was significantly reduced to 7 days—representing a 73% reduction in total reaction time as deduced from the biotransformation products and confirmed by LC-MS, NMR spectroscopic data, as well as a comparison with synthetically prepared metabolites. Our study provides the first report of the metabolism of FCF by C. elegans. These findings suggest that C. elegans can produce FCF secondary metabolites consistent with those produced via mammalian metabolism and could be used as a more efficient, cost-effective, and ethical alternative for producing those metabolites in useful quantities for toxicological studies. Full article

Aflatoxin B1 (AFB1) is a hazardous mycotoxin that often contaminates animal feed and may potentially induce severe liver damage if ingested. The liver is the primary organ responsible for AFB1 detoxification through enzyme-catalyzed xenobiotic metabolism and bile acid (BA)-associated excretion. In this study, we sought to investigate whether exogenous BA improves hepatic AFB1 detoxification to alleviate AFB1-induced liver injury in broiler chickens. Five-day-old broiler chicks were randomly assigned to three groups. CON and AFB1 received a basal diet; AFB1 + BA received a basal diet with 250 mg/kg BA for 20 days. After a 3-day pre-feed, AFB1 and AFB1 + BA were daily gavaged with 250 μg/kg BW AFB1, while CON received gavage solvent for AFB1 treatment. Dietary BA supplementation protected chickens from AFB1-induced hepatic inflammation and oxidative stress. The hepatic biotransformation of AFB1 to its metabolite AFBO was improved, with accelerated excretion to the gallbladder and cecum. Accordantly, AFB1-induced down-regulation of detoxification genes, including cytochrome P450 enzymes, glutathione S-transferases, and the bile salt export pump, was rescued by BA supplementation. Moreover, liver X receptor α, suppressed by AFB1, was enhanced in BA-treated broiler chickens. These results indicate that dietary BA supplementation improves hepatic AFB1 detoxification and excretion through LXRα-involved regulation of xenobiotic enzymes. Full article