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Ciguatoxins (CTXs), potent neurotoxins produced by dinoflagellates of the genera Gambierdiscus and Fukuyoa, accumulate in commonly consumed fish species, causing human ciguatera poisoning. Field collections of Pacific reef fish reveal that consumed CTXs undergo oxidative biotransformations, resulting in numerous, often toxified analogs. Following our study showing rapid CTX accumulation in flesh of an herbivorous fish, we used the same laboratory model to examine the tissue distribution and metabolization of Pacific CTXs following long-term dietary exposure. Naso brevirostris consumed cells of Gambierdiscus polynesiensis in a gel food matrix over 16 weeks at a constant dose rate of 0.36 ng CTX3C equiv g-1 fish d-1. CTX toxicity determination of fish tissues showed CTX activity in all tissues of exposed fish (eight tissues plus the carcass), with the highest concentrations in the spleen. Muscle tissue retained the largest proportion of CTXs, with 44% of the total tissue burden. Moreover, relative to our previous study, we found that larger fish with slower growth rates assimilated a higher proportion of ingested toxin in their flesh (13% vs. 2%). Analysis of muscle extracts revealed the presence of CTX3C and CTX3B as well as a biotransformed product showing the m/z transitions of 2,3-dihydroxyCTX3C. This is the first experimental evidence of oxidative transformation of an algal CTX in a model consumer and known vector of CTX into the fish food web. These findings that the flesh intended for human consumption carries the majority of the toxin load, and that growth rates can influence the relationship between exposure and accumulation, have significant implications in risk assessment and the development of regulatory measures aimed at ensuring seafood safety.

Subsurface treatment systems, such as constructed wetlands, riverbank filtration systems, and managed aquifer recharge systems, offer a low-cost means of removing trace organic contaminants from treated municipal wastewater. To assess the processes through which trace organic contaminants are removed in subsurface treatment systems, pharmaceuticals and several major metabolites were measured in porewater, sediment, and plants within a horizontal levee (i.e., a subsurface flow wetland that receives treated municipal wastewater). Concentrations of trace organic contaminants in each wetland compartment rapidly declined along the flow path. Mass balance calculations, analysis of transformation products, microcosm experiments, and one-dimensional transport modeling demonstrated that more than 60% of the contaminant removal could be attributed to transformation. Monitoring of the system with and without nitrate in the wetland inflow indicated that relatively biodegradable trace organic contaminants, such as acyclovir and metoprolol, were rapidly transformed under both operating conditions. Trace organic contaminants that are normally persistent in biological treatment systems (e.g., sulfamethoxazole and carbamazepine) were removed only when Fe(III)- and sulfate-reducing conditions were observed. Minor structural modifications to trace organic contaminants (e.g., hydroxylation) altered the pathways and extents of trace organic contaminant transformation under different redox conditions. These findings indicate that subsurface treatment systems can be designed to remove both labile and persistent trace organic contaminants via transformation if they are designed and operated in a manner that results in sulfate-and Fe(III)-reducing conditions.

Abstract Background Vanillin is a flavoring substance derived from vanilla. We are currently developing a biotransformation method for vanillin production using glucose. This report describes the last step in vanillin production: the conversion of vanillic acid to vanillin. First, we selected Corynebacterium glutamicum as the host owing to its high vanillin resistance. The aromatic aldehyde reductase gene (NCgl0324) and vanillic acid demethylase protein subunits A and B gene (vanAB, NCgl2300-NCgl2301) were deleted in C. glutamicum genome to avoid vanillin degradation. Next, we searched for an aromatic carboxylic acid reductase (ACAR), which converts vanillic acid to vanillin. Seventeen ACAR homologs from various organisms were introduced into C. glutamicum. Results In vivo conversion experiments showed that eight ACARs were successfully expressed and produced vanillin. In terms of conversion activity and substrate specificity, the ACARs from Gordonia effusa, Coccomyxa subellipsoidea, and Novosphingobium malaysiense are promising candidates for commercial production. Conclusions Corynebacterium glutamicum harboring Gordonia effusa ACAR produced 22 g/L vanillin, which is, to the best of our knowledge, the highest accumulation reported in the literature. At the same time, we discovered ACAR from Novosphingobium malaysiense and Coccomyxa subellipsoidea C-169 with high substrate specificity. These findings are useful for reducing the byproducts.

Abstract Background The fish embryo acute toxicity (FET) test with the zebrafish (Danio rerio) was developed to assess the acute fish toxicity of chemicals or environmental samples as a replacement for the Acute Fish Test (AFT) with juvenile fish. However, the FET is not yet established in the regulatory context. One reason is the (postulated) difference between the biotransformation capacities of embryos and juvenile fish. The present study was designed to develop a procedure for external metabolization of test substances prior to testing in the FET. The workflow allows simultaneous exposure of the embryos to the maternal substances and their potential metabolites throughout the entire exposure period. After a 2 h incubation of the samples at 37 °C with non-toxic concentrations of a rat liver S9 homogenate or an animal-free (ewoS9R) metabolization system, freshly fertilized zebrafish embryos are added and incubated up to 120 h post-fertilization at 26 °C. Five biotransformable model substances (allyl alcohol, benzo[a]pyrene (B[a]P), chlorpyrifos (CP), tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and bisphenol A (BPA)) were evaluated for embryotoxicity with and without external metabolization. Results Only for allyl alcohol, external metabolization with both rat S9 and ewoS9R resulted in significantly higher embryotoxicity than under non-premetabolized conditions and, thus, in a better correlation of FET and AFT data. For B[a]P, CP, TDCPP and BPA, there was no relevant difference between data derived from the FET (with and without pre-metabolization) and literature AFT data; even though the FET results with and without pre-metabolization differed significantly for BPA (with rat S9 and ewoS9R) and TDCPP (rat S9 only). Conclusions External pre-metabolization appears a promising add-on to the FET protocol to improve the correlation with AFT data of certain biotransformable substances and might help to strengthen the FET as an alternative to the AFT and finally to reduce or replace sentient animals used for acute fish toxicity data in the regulatory context. Graphical Abstract

Abstract Background Isoquercitrin (quercetin-3-O-β-D-glucopyranoside) has exhibited promising therapeutic potentials as cardioprotective, anti-diabetic, anti-cancer, and anti-viral agents. However, its structural complexity and limited natural abundance make both bulk chemical synthesis and extraction from medical plants difficult. Microbial biotransformation through heterologous expression of glycosyltransferases offers a safe and sustainable route for its production. Despite several attempts reported in microbial hosts, the current production levels of isoquercitrin still lag behind industrial standards. Results Herein, the heterologous expression of glycosyltransferase UGT78D2 gene in Bacillus subtilis 168 and reconstruction of UDP-glucose (UDP-Glc) synthesis pathway led to the synthesis of isoquercitrin from quercetin with titers of 0.37 g/L and 0.42 g/L, respectively. Subsequently, the quercetin catabolism blocked by disruption of a quercetin dioxygenase, three ring-cleavage dioxygenases, and seven oxidoreductases increased the isoquercitrin titer to 1.64 g/L. And the hydrolysis of isoquercitrin was eliminated by three β-glucosidase genes disruption, thereby affording 3.58 g/L isoquercitrin. Furthermore, UDP-Glc pool boosted by pgi (encoding glucose-6-phosphate isomerase) disruption increased the isoquercitrin titer to 10.6 g/L with the yield on quercetin of 72% and to 35.6 g/L with the yield on quercetin of 77.2% in a 1.3-L fermentor. Conclusion The engineered B. subtilis strain developed here holds great potential for initiating the sustainable and large-scale industrial production of isoquercitrin. The strategies proposed in this study provides a reference to improve the production of other flavonoid glycosides by engineered B. subtilis cell factories.

In order to develop chitin and chitosan bioconversion of active oligosaccharides and achieve the application of chitinase in food preservation and biocontrol, chitinase (ChiA-Sa62) was isolated and purified from Streptomyces aureofaciens XZ-Sa62, and its bioconversion and antibacterial function were studied. ChiA-Sa62 was purified by Q-Sepharose Fast Flow, Sephadex G-100 chromatography, and reverse phase high performance liquid chromatography (RP-HPLC), with a purification factor of 41.3 and a specific activity of 1 119.8 U/mg. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) showed that ChiA-Sa62 was a single subunit protein with a molecular weight of 62.55 kDa. ChiA-Sa62 exhibited maximum activity at 50 ℃ and pH 5, and exhibited good stability below 60 ℃ and within pH range of 3.0-9.0. Ca2+, Mn2+, Mg2+, and Co2+ could activate enzyme activity. ChiA-Sa62 had a specific endonucleating hydrolysis activity on chitin and chitosan with a degree of deacetylation of 75%. Thin layer chromatography (TLC) showed that the hydrolysis products were 2-5 N-acetylglucosamine (GlcNAc) units of chitosan oligosaccharides and 2-4 D-glucosamine (GlcN) units of chitosan oligosaccharides, respectively. The colloidal chitin was used as the substrate, with ChiA-Sa62 Km and Vmax values of 2.75 mg/mL and 64.52 U/mg, respectively. ChiA-Sa62 strongly inhibited the tested pathogenic fungi, and propidium iodide (PI) staining showed that ChiA-Sa62 disrupted the integrity of the cell membrane of Botrytis cinerea. The hydrolyzed chitosan oligosaccharide had antibacterial activity against pathogenic G- bacteria (Escherichia coli and Pseudomonas aeruginosa) and G+ bacteria (Staphylococcus aureus and Bacillus cereus). LIVE/DEAD staining showed that chitosan oligosaccharide could cause the death of S. aureus. ChiA-Sa62 chitin and chitosan have great potentials for application in biotransformation, food preservation, and biological control.

Monoterpenes, such as Geraniol (G), Geranyl acetate (GA), Citral (CT), Limonene (LN), and Linalool (LL), are the most widely used phytochemicals in the aroma, food, and pharmaceutical industries. Here, we screened several bacteria and fungi to assess their potential to biotransform the selected monoterpenes (G, GA, CT, LN, and LL) through the substrate toxicity test. Three bacteria Pseudomonas fluorescens MTCC2421, Streptococcus mutans MTCC497, and Escherichia coli were found to be resistant to G, GA, and LN while two P. aeruginosa, and S. epidermidis MTTC 435 to GA and LN. In general, all fungal strains did not show resistance to any of the monoterpenes used, except Candida albicans and Fusarium oxysporum, which were slightly resistant to lower concentrations (0.05-0.1%) of GA. Interestingly, none of the bacteria and fungi showed any resistance to CT. The maximum concentrations of monoterpenes to which bacteria exhibited resistance ranged from 0.05-0.2%. The growth and biomass profiles of bacteria revealed that P. fluorescens and S. mutans grew well in the presence of monoterpenes GA and LN. Based on this, Pseudomonas fluorescens was capable of biotransforming GA and LN, while S. mutans only LN. The biotransformation of GA by P. fluorescens produced G and LL on the day 5th and 7th of the incubation. Hence, the study revealed the three potential bacteria, which may be useful in producing new aromatic derivatives from selected monoterpenes through biotransformation.

Due to low immobilized ligand density, limited binding capacity, and severe interference from serum proteins, developing ideal peptide-based biomaterials for precise recognition and in vivo analysis of biopharmaceuticals remains a huge challenge. In this study, mimotope peptide modified pompon mum-like biomimetic magnetic microparticles (MMPs, 3.8 μm) that mimic the specific functionalities of CD20 on malignant B cells were developed for the first time. Benefit from the numerous ligand binding sites (Ni2+) on the pompon mum-like MMPs, these novel materials achieved ≥10 times higher peptide ligand densities (>2300 mg/g) and antibody binding capacities (1380 mg/g) compared to previous reported biomaterials. Leveraging the high specificity of the mimotope peptide, rituximab can be precisely recognized and enriched from cell culture media or serum samples. We also established an LC‒MS/MS method using the MMPs for tracking rituximab biotransformation in patient serum. Intriguingly, deamidation of Asn55 and Asn33, as well as oxidation of Met81 and Met34 were observed at the key complementarity determining regions of rituximab, which could potentially influence antibody function and require careful monitoring. Overall, these versatile biomimetic MMPs demonstrate superior recognition and enrichment capabilities for target antibodies, offering interesting possibilities for biotransformation analysis of biopharmaceuticals in patient serum.

Abstract Bufadienolides, naturally occurring steroids primarily found in toads, have garnered attention for their pharmacological properties and ecological significance. In this study, we isolated and identified 21 bufadienolides from the gallbladders of Bufo gargarizans, comprising four new compounds and 17 known ones. Notably, the predominance of 15 bufadienolides with a 3α-OH configuration in toad bile differs significantly from the 3β-OH bufadienolides found in venom secreted by toad glands. Moreover, our investigation into the biotransformation of 3β-OH and 3α-OH bufadienolides in the liver and kidney tissues of toads revealed an irreversible conversion from 3β-OH to 3α-OH bufadienolides, suggesting a crucial role in toad self-detoxification. These findings provide valuable insights into the structural diversity of bufadienolides and advance our understanding of their medical and ecological significance. Graphical Abstract

Background: Vanillin is a flavoring substance derived from vanilla. We are currently developing a biotransformation method for vanillin production using glucose. This report describes the last step in vanillin production: the conversion of vanillic acid to vanillin. First, we selected Corynebacterium glutamicum as the host owing to its high vanillin resistance. The aromatic aldehyde reductase gene (NCgl0324) and vanillic acid demethylase protein subunits A and B gene (vanAB, NCgl2300-NCgl2301) were deleted in C. glutamicum genome to avoid vanillin degradation. Next, we searched for an aromatic carboxylic acid reductase (ACAR), which converts vanillic acid to vanillin. Seventeen ACAR homologs from various organisms were introduced into C. glutamicum. Results: In vivo conversion experiments showed that eight ACARs were successfully expressed and produced vanillin. In terms of conversion activity and substrate specificity, the ACARs from Gordonia effusa, Coccomyxa subellipsoidea, and Novosphingobium malaysiense are promising candidates for commercial production. Conclusions: Corynebacterium glutamicum harboring Gordonia effusa ACAR produced 22 g/L vanillin, which is, to the best of our knowledge, the highest accumulation reported in the literature. At the same time, we discovered ACAR from Novosphingobium malaysiense and Coccomyxa subellipsoidea C-169 with high substrate specificity. These findings are useful for reducing the byproducts. [ABSTRACT FROM AUTHOR]

AbstractHeavy metals (HMs) are widely used in various industries. High concentrations of HMs can be severely toxic to plants, animals and humans. Microorganism-based bioremediation has shown significant potential in degrading and detoxifying specific HM contaminants. In this study, we cultivated a range of bacterial strains in liquid and solid nutrient medium containing different concentrations of different HMs to select and analyze bacteria capable of transforming HMs. The bacterial strains most resistant to selected HMs and exhibiting the ability to remove HMs from contaminated soils were identified. Then, the bacterial species capable of utilizing HMs in soil model experiments were selected, and their ability to transform HMs was evaluated. This study has also generated preliminary findings on the use of plants for further removal of HMs from soil after microbial bioremediation. Alcaligenes faecalis, Delftia tsuruhatensis and Stenotrophomonas sp. were selected for their ability to grow in and utilize HM ions at the maximum permissible concentration (MPC) and two times the MPC. Lysinibacillus fusiformis (local microflora) can be used as a universal biotransformation tool for many HM ions. Brevibacillus parabrevis has potential for the removal of lead ions, and Brevibacillus reuszeri and Bacillus safensis have potential for the removal of arsenic ions from the environment. The bacterial species have been selected for bioremediation to remove heavy metal ions from the environment. [ABSTRACT FROM AUTHOR]

Practical Application The utilization of coffee leaves in kombucha production has intrigued researchers; however, the lack of understanding regarding the characteristics of coffee leaf kombucha (CK) and its differentiation from black tea kombucha (BK) has impeded its application in the beverage industry. Therefore, this study aimed to characterize and compare the physiochemical properties, phytochemical compositions, antioxidant activity, and α‐glucosidase inhibitory ability of kombucha prepared from the leaves of Coffea arabica (CK) and black tea (Camellia sinensis, BK) and their extracts (CT and BT). After fermentation, pH and the contents of total sugars, reducing sugars, and free amino acids of BK and CK were decreased, whereas the levels of total acids and organic acids, such as gluconic, lactic, and acetic acid were increased. Notably, the concentration of vitamin C in CK was 48.9% higher than that in BK. HPLC analysis exhibited that 5‐caffeoylquinic acid in CT was significantly decreased by 48.0% in CK, whereas the levels of 3‐caffeoylquinic acid and 4‐caffeoylquinic acid were significantly increased after fermentation. The content of caffeine was significantly (p < 0.05) reduced by 9.5% and 22.0% in BK and CK, respectively, whereas the theobromine level was significantly increased in CK. Notably, CK has superior total phenolic and flavonoid contents and antioxidant activity than BK, whereas BK possesses higher α‐glucosidase inhibitory capacity. Electronic nose analysis demonstrated that sulfur‐containing organics were the main volatiles in both kombuchas, and fermentation significantly increased their levels. Our study indicates that coffee leaves are a promising resource for preparing kombucha.This article investigates the differences in physicochemical properties, bioactive constituents, antioxidant activity, and α‐glucosidase inhibitory activity of kombucha preparation from black tea and coffee leaves. We have found that after fermentation BK had brighter soup color and higher α‐glucosidase inhibitory capacity, whereas CK had higher levels of total phenols, flavonoids, vitamin C, and antioxidants and lower contents of sugars. This study provides valuable information for the preparation of CK with high‐quality attributes and antioxidant activity. [ABSTRACT FROM AUTHOR]

Fertilisers maintain agricultural productivity for world needs, Despite the numerous advantages of controlled release fertilisers (CRFs), production expenses and impacts on the environment and soil quality limit widespread adoption. This research focuses on valorising agro-industrial waste through a biotransformation process (anaerobic and aerobic digestion). The resulting biofertilisers, when associated with phosphogypsum (PG) using the simplex-centroid design, create organo-mineral fertilisers with controlled nutrient release. A balanced formulation with 33.33% of each component (digestate, compost, and phosphogypsum) demonstrates a promising sustainable approach, contributing nutritional elements with exceptional control and sustained release characteristics, all without the previous use of coating materials. This environment-friendly approach accords with the Sustainable Development Goals, particularly 2, 3, 12, and 15. [ABSTRACT FROM AUTHOR]

In the current study, chromatographic and in silico techniques were applied to investigate the biotransformation of ethyl 5-(4-bromophenyl)-1-(2-(2-(2-hydroxybenzylidene) hydrazinyl)-2-oxoethyl)-2-methyl-1H-pyrrole-3-carboxylate (11b) in hepatocytic media. The initial chromatographic procedure was based on the employment of the conventional octadecyl stationary phase method for estimation of the chemical stability. Subsequently, a novel and rapid chromatographic approach based on a phenyl–hexyl column was developed, aiming to separate the possible metabolites. Both methods were performed on a Dionex 3000 ThermoScientific (ACM 2, Sofia, Bulgaria) device equipped with a diode array detector set up at 272 and 279 nm for analytes detection. An acetonitrile: phosphate buffer of pH 3.5: methanol (17:30:53 v/v/v) was eluted isocratically as a mobile phase with a 1 mL/min flow rate. A preliminary purification from the biological media was achieved by protein precipitation with methanol. A validation procedure was carried out, where the method was found to correspond to all ICH (Q2) and M10 set criteria. Additionally, an in silico-based approach with the online server BioTransformer 3.0 was applied in an attempt to predict the possible metabolites of the title compound 11b. It was hypothesized that four CYP450 isoforms (1A2, 2C9, 3A4, and 2C8) were involved in the phase I metabolism, resulting in the formation of 12 metabolites. Moreover, docking studies were conducted to evaluate the formation of stable complexes between 11b and the aforementioned isoforms. The obtained data indicated three metabolites as the most probable products, two of which (M9_11b and M10_11b) were synthesized by a classical approach for verification. Finally, liquid chromatography with a mass detector was implemented for comprehensive and summarized analysis, and the obtained results revealed that the metabolism of the 11b proceeds possibly with the formation of glucuronide and glycine conjugate of M11_11b. [ABSTRACT FROM AUTHOR]

Betulinic acid (BA), a betulin derivative, is an important plant-based natural product. BA has many biological activities and attracts attention especially as a promising antitumour drug. Extraction from plants or semi-synthesis from betulin are the common methods to obtain BA, but these methods have some drawbacks. In recent years, microbial biotransformation of betulin to BA has been anticipated as an alternative method. Betulin is abundant in the outer bark of birch (Betula spp.) and obtained from these plants, however endophytes of Betula spp. have not been investigated for biotransformation of betulin to BA before. Therefore, this study aimed to investigate the culturable endophytes of Betula pubescens var. litwinowii (Doluch.) Ashburner & McAll and to determine their biotransformation capacity of betulin to BA. To this end, bacterial and fungal endophytes were isolated from the surface-sterilized root, stem, and branch samples. A total of 37 endophytes (11 bacteria and 26 fungi) were identified by polyphasic approach. All endophytes were screened for the biotransformation of betulin to BA. Betulin and BA content of the extracts were determined by RP-HPLC analysis. Two different bacterial and fungal biotransformation processes were designed. It was found that the fungus BRF59 produced BA via betulin biotransformation under the Fungal Biotransformation Process-2 when the fungus was acclimatized to betulin before biotransformation, and glycerol was used as a carbon source, instead of glucose, during bioprocess. The highest BA yield and BA concentration was obtained as 12.22±0.94 % and 80.85±2.64 µg/ml, respectively, under non-optimized conditions. The fungal isolate BRF59, belonging to the genus Fusarium according to ITS analysis, was further identified based on RPB2 sequence analysis and found that Fusarium lacertarum. In conclusion, this study demonstrated that betulin was biotransformed to BA by an endophytic fungus isolated from the genus Betula for the first time. F. lacertarum BRF59 might be a good candidate for production of BA through betulin biotransformation and, using glycerol as a carbon source during biotransformation might enable this by-product to convert value-added chemical. [Display omitted] • Culturable endophytes of Betula pubescens var. litwinowii (Doluch) was investigated. • Biotransformation of betulin to betulinic acid by endophytes was investigated. • Fusarium lacertarum BRF59 produced betulinic acid via betulin biotransformation. • The highest betulinic acid production was 80.85±2.64 µg/ml. • Acclimatization to betulin and using glycerol induced betulinic acid production. [ABSTRACT FROM AUTHOR]

The α-L-arabinofuranosidase enzyme plays a crucial role in the degradation of ginsenosides. In this study, we successfully cloned and expressed a novel α-L-arabinofuranosidase bsafs gene (1503 bp, 501 amino acids, 55 kDa, and pI = 5.4) belonging to glycosyl hydrolase (GH) family 51 from Bacillus subtilis genome in Escherichia coli BL21 cells. The recombinant protein Bsafs was purified using Ni2+ sepharose fastflow affinity chromatography and exhibited a specific activity of 2.91 U/mg. Bsafs effectively hydrolyzed the α-L-arabinofuranoside at C20 site of ginsenoside Rc to produce Rd as the product. The Km values for hydrolysis of pNP-α-L-arabinofuranoside (pNPαAraf) and ginsenoside Rc were determined as 0.74 and 4.59 mmol/L, respectively; while the Vmax values for these substrates were found to be 24 and 164 μmol/min/mg, respectively; furthermore, the Kcat values for these enzymes were calculated as 22.3 and 1.58 S−1 correspondingly. [ABSTRACT FROM AUTHOR]

Gastrodin is an important plant-derived medicinal ingredient that has been used to treat various diseases. Biosynthesis is an effective strategy for gastrodin production, but the expression and activity of natural glycosyltransferases (GTs) is generally a limiting factor. To identify highly efficient GTs, four plant-derived enzymes were identified by homologous sequence analysis and expressed in Escherichia coli BL21 (DE3). A GT from Arabidopsis thaliana (AtUGT) displayed the highest activity of 0.45 U/mg, with an optimal pH of 9.0 and high thermostability. Under optimized conditions, 10 mM p-hydroxybenzyl alcohol and uridine diphosphate glucose were converted into 2.67 g/L gastrodin, corresponding to a conversion rate of 94.34% in 12 h. Furthermore, molecular docking simulations were performed between AtUGT and p-hydroxybenzyl alcohol, revealing the catalytic mechanism of AtUGT. This study provides a novel and effective biocatalyst for the synthesis of gastrodin. [ABSTRACT FROM AUTHOR]

The stems and leaves of Panax notoginseng contain high saponins, but they are often discarded as agricultural waste. In this study, the predominant ginsenosides Rg1, Rc, and Rb2, presented in the stems and leaves of ginseng plants, were biotransformed into value-added rare ginsenosides F1, compound Mc1 (C-Mc1), and Rd2, respectively. A fungal strain YMS6 (Penicillium sp.) was screened from the soil as a biocatalyst with high selectivity for the deglycosylation of major ginsenosides. Under the optimal fermentation conditions, the yields of F1, C-Mc1, and Rd2 were 97.95, 68.64, and 79.58%, respectively. This study provides a new microbial resource for the selective conversion of protopanaxadiol-type and protopanaxatriol-type major saponins into rare ginsenosides via the whole-cell biotransformation and offers a solution for the better utilization of P. notoginseng waste. [ABSTRACT FROM AUTHOR]

Chlorzoxazone (CZX), a benzoxazolone derivative, has been approved for the treatment of musculoskeletal disorders to relieve localized muscle spasm. However, its idiosyncratic toxicity reported in patients brought attention, particularly for hepatotoxicity. The present study for the first time aimed at the relationship between CZX-induced hepatotoxicity and identification of oxirane intermediate resulting from metabolic activation of CZX. Two N-acetylcysteine (NAC) conjugates (namely M1 and M2) and two glutathione (GSH) conjugates (namely M3 and M4) were detected in rat & human microsomal incubations with CZX (200 μM) fortified with NAC or GSH, respectively. The formation of M1-M4 was NADPH-dependent and these metabolites were also observed in urine or bile of SD rats given CZX intragastrically at 10 mg/kg or 25 mg/kg. NAC was found to attach at C-6' of the benzo group of M1 by sufficient NMR data. CYPs3A4 and 3A5 dominated the metabolic activation of CZX. The two GSH conjugates were also observed in cultured rat primary hepatocytes after exposure to CZX. Inhibition of CYP3A attenuated the susceptibility of hepatocytes to the cytotoxicity of CZX (10–400 μM). The in vitro and in vivo studies provided solid evidence for the formation of oxirane intermediate of CZX. This would facilitate the understanding of the underlying mechanisms of toxic action of CZX. [ABSTRACT FROM AUTHOR]

Key message: Both bacterial and fungal endophytes exhibited one or more plant growth-promoting (PGP) traits. Among these strains, the Paenibacillus peoriae SYbr421 strain demonstrated the greatest activity in the direct biotransformation of tuber powder from D. nipponica into diosgenin. Endophytes play crucial roles in shaping active metabolites within plants, significantly influencing both the quality and yield of host plants. Dioscorea nipponica Makino accumulates abundant steroidal saponins, which can be hydrolyzed to produce diosgenin. However, our understanding of the associated endophytes and their contributions to plant growth and diosgenin production is limited. The present study aimed to assess the PGP ability and potential of diosgenin biotransformation by endophytes isolates associated with D. nipponica for the efficient improvement of plant growth and development of a clean and effective approach for producing the valuable drug diosgenin. Eighteen bacterial endophytes were classified into six genera through sequencing and phylogenetic analysis of the 16S rDNA gene. Similarly, 12 fungal endophytes were categorized into 5 genera based on sequencing and phylogenetic analysis of the ITS rDNA gene. Pure culture experiments revealed that 30 isolated endophytic strains exhibited one or more PGP traits, such as nitrogen fixation, phosphate solubilization, siderophore synthesis, and IAA production. One strain of endophytic bacteria, P. peoriae SYbr421, effectively directly biotransformed the saponin components in D. nipponica. Moreover, a high yield of diosgenin (3.50%) was obtained at an inoculum size of 4% after 6 days of fermentation. Thus, SYbr421 could be used for a cleaner and more eco-friendly diosgenin production process. In addition, based on the assessment of growth-promoting isolates and seed germination results, the strains SYbr421, SYfr1321, and SYfl221 were selected for greenhouse experiments. The results revealed that the inoculation of these promising isolates significantly increased the plant height and fresh weight of the leaves and roots compared to the control plants. These findings underscore the importance of preparing PGP bioinoculants from selected isolates as an additional option for sustainable diosgenin production. [ABSTRACT FROM AUTHOR]

Microbial biotransformation is an efficient process for making high-value natural products in a controlled and environment friendly manner. Bioconversion of low value monoterpenes to high value products using fungi offers an effective strategy for producing desirable products. Efficient conversion of D-limonene, a monoterpene, into carveol is reported in this study by using an endophytic fungus, Aspergillus flavus IIIMF4012, isolated from the root of Rosa damascena. By optimizing different parameters, isolated strain resulted in the hydroxylation of D-limonene to carveol effectively and the process was carried out at 1 L scale which resulted in the formation of a mixture of carveol isomers (cis- carveol 23.82%, trans- carveol 17.21%). Further, the biotransformation was scaled up in 5 L fermenter and the product was characterized by GC-MS and NMR (1H & 13C). As a result, an efficient procedure was established for biotransforming a low-value molecule i.e., D-limonene into a high-value product i.e.,carveol. [ABSTRACT FROM AUTHOR]

Herein, we report the use of whole cells of Brazilian marine-derived fungi in the biotransformation and biodegradation of organic compounds, particularly, Knoevenagel adducts. A preliminary screening with five marine-derived fungi revealed that these microorganisms promoted the bioreduction and biodegradation of four Knoevenagel adducts. Additionally, a biotransformation pathway for these compounds was proposed, which suggested the presence of ene-reductase and alcohol dehydrogenase in the marine-derived fungi, which catalysed the microbial transformation of the substrates. In summary, the fast biodegradation of organic molecules has an ecological relevance since several of these compounds and their biotransformed products have aquatic environment impact. [ABSTRACT FROM AUTHOR]

Verbenone is a natural monoterpene present as an essential component in rosemary oil from Rosmarinus officinalis, Verbena triphylla and Eucalyptus globule. Microbial biotransformation of monoterpenoids to value-added products has immense industrial potential. This study involves the biotransformation of (-)-verbenone to (-)-10-hydroxyverbenone by a fungus i.e. Talaromyces purpurogenus strain MRS-F13 in fermentation broth during the exponential phase. Biotransformation reaction has been successfully demonstrated at 15 L scale in the bioreactor with 70% conversion within 96 h. The anti-inflammatory activity investigations revealed that (-)-verbenone and its biotransformed product exhibited moderate inhibition of TNF-α and nitric oxide, whereas (-)-10-hydroxyverbenone presented an improved anti-oxidant activity. Talaromyces purpurogenus catalysed biotransformation of (-)-verbenone to (-)-10-hydroxyverbenone has been demonstrated. Approximately 70% bioconversion was obtained in 96 h in submerged culture at 15L bioreactor scale. Biotransformed product (-)-10-hydroxyverbenone has shown improved anti-inflammatory activity without cytotoxicity. [ABSTRACT FROM AUTHOR]

In this work, biotransformations of pregnenolone 1 by Ulocladium chartarum MRC 72584, Cladosporium sphaerospermum MRC 70266 and Cladosporium cladosporioides MRC 70282 have been reported. U. chartarum MRC 72584 only hydroxylated 1 at C-7β and hydroxylated 1 at either C-7β or C-14α, accompanied with a concurrent epoxidation from the β-face. The same fungus hydroxylated a small amount of 1 at both C-7 and C-14α, accompanied with a subsequent oxidation at C-7. 3β,14α-Dihydroxy-5β,6β-epoxypregnan-20-one 4 and 3β,7β-dihydroxy-5β,6β-epoxypregnan-20-one 5 obtained from the incubation of 1 with this fungus were determined as new metabolites. C. sphaerospermum MRC 70266 converted most of 1 into a 3-keto-4-ene steroid and independently hydroxylated it at C-6α, C-6β and C-7β. This fungus also hydroxylated 1 at C-7 and C-11α and then oxidized it at C-7. C. cladosporioides MRC 70282 converted almost half of 1 into a 3-keto-4-ene steroid. The same fungus reduced some of this 3-keto-4-ene steroid by a 5α-reductase activity while it hydroxylated the rest at C-6α and C-6β. [ABSTRACT FROM AUTHOR]

AbstractCr(VI) is one of the most widely used elements in various industrial sectors and, hence, extensively found as a toxicant in the ecosystem. The biotransformation of Cr(VI) via microorganisms is considered an ecofriendly approach for its detoxification. The present study focused on the isolation of an indigenous bacterium from municipal solid waste dumpsite soils with relatively higher Cr(VI) resistance (>1000 mg L−1 in broth) and a 97% reduction of Cr(VI) (100 mg L−1) under conditions of 37 °C, pH 7, and 120 rpm in 48 h. The biochemical and 16 S rRNA gene sequencing showed that the isolate exhibits 99% similarity with Mammaliicoccus sciuri. Partial reductase gene sequences were retrieved, showing 96% similarity to NADPH-dependent FMN reductases. Fourier transform infrared spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy showed the presence of Cr products on bacterial cells. X-ray photoelectron spectroscopic analysis confirmed the valence state of the residual Cr present as Cr(III). Furthermore, quantitative localization of reduced Cr products and transmission electron microscopic analysis confirmed the intracellular accumulation of the Cr(III). A multifaceted mechanism, including surface adsorption and bioaccumulation after biotransformation, confers a potential solid identity for the strain Mammaliicoccus sciuri jv5 toward Cr(VI) remediation in the Cr polluted environment niche. [ABSTRACT FROM AUTHOR]

In microbial electrochemical cells (MECs), electroactive microbial biofilms can transmit electrons from organic molecules to anodes. To further understand the production of anodic biofilms, it is essential to investigate the composition and distribution of extracellular polymeric substance (EPS) in the MECs. In this study, the structure of EPS was examined in microbial electrolysis cells from mixed cultures forming biofilm using carbon fiber fabric anode. EPS was extracted from the anode biofilm of microbial electrolysis cells inoculated with mixed microbial culture. The anode biofilm yielded 0.4 mg of EPS, of which 51.2% was humic substance, 16.2% was protein, 12.6% was carbohydrates, and 20% consisted of undetermined substances. Using epifluorescence microscopy, the composition of bacterial cells and their location inside EPS were studied, and the distribution of microbial communities was compared based on current density results in the presence of various carbohydrates. On the electrode surface, bacteria and EPS gathered or overlapped in various locations can affect microbial electrochemical performance. Our findings showed that EPS formation in electroactive biofilms would be important for enhanced efficiency of electricity- or hydrogen-producing microbial electrolysis cells. [ABSTRACT FROM AUTHOR]

Monoterpenes, such as Geraniol (G), Geranyl acetate (GA), Citral (CT), Limonene (LN), and Linalool (LL), are the most widely used phytochemicals in the aroma, food, and pharmaceutical industries. Here, we screened several bacteria and fungi to assess their potential to biotransform the selected monoterpenes (G, GA, CT, LN, and LL) through the substrate toxicity test. Three bacteria Pseudomonas fluorescens MTCC2421, Streptococcus mutans MTCC497, and Escherichia coli were found to be resistant to G, GA, and LN while two P. aeruginosa, and S. epidermidis MTTC 435 to GA and LN. In general, all fungal strains did not show resistance to any of the monoterpenes used, except Candida albicans and Fusarium oxysporum, which were slightly resistant to lower concentrations (0.05-0.1%) of GA. Interestingly, none of the bacteria and fungi showed any resistance to CT. The maximum concentrations of monoterpenes to which bacteria exhibited resistance ranged from 0.05-0.2%. The growth and biomass profiles of bacteria revealed that P. fluorescens and S. mutans grew well in the presence of monoterpenes GA and LN. Based on this, Pseudomonas fluorescens was capable of biotransforming GA and LN, while S. mutans only LN. The biotransformation of GA by P. fluorescens produced G and LL on the day 5th and 7th of the incubation. Hence, the study revealed the three potential bacteria, which may be useful in producing new aromatic derivatives from selected monoterpenes through biotransformation. [ABSTRACT FROM AUTHOR]

Tyrosinase hydroxylates monophenols to ortho-diphenols through monophenolase activity and oxidizes the ortho-diphenols to ortho-quinones through diphenolase activity. Here, the biotransformation of naringenin, a flavonoid having various biological activities, was attempted using a recombinant tyrosinase of Bacillus megaterium DY804 strain (DY804) as a biocatalyst. DY804 sequentially produced two hydroxylated products, eriodictyol (a catechol) and dihydrotricetin (a gallol), from naringenin (a phenol) in the presence of L-ascorbic acid. The k cat and K m values of DY804 toward naringenin were 161 min−1 and 1060 μM, respectively, to produce eriodictyol. When eriodictyol was the substrate, the k cat and K m of DY804 were 25.7 min−1 and 130 μM, respectively. The maximum concentrations of eriodictyol and dihydrotricetin produced by DY804 were 1074 μM (54% yield) and 315 μM (16% yield), respectively. The maximum productivities were 1038 μM/h (299 mg/L/h) of eriodictyol and 241 μM/h (73 mg/L/h) of dihydrotricetin. The activity of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase was reduced by naringenin, eriodictyol, and dihydrotricetin, their half maximal inhibitory concentration (IC 50) values were 1192, 2401, and 751 µM, respectively. Therefore, three tested flavonoid compounds can be used as antihyperlipidemic agents. It is suggested that DY804 can be applied in the pharmaceutical industry as a biocatalyst to produce high-value-added flavonoids. [Display omitted] • Tyrosinase DY804 produced dihydrotricein from naringenin through eriodictyol. • Kinetic parameters of DY804 toward naringenin and eriodicytol were determined. • Ability of DY804 to produce catechol and gallol compounds was investigated. • Naringenin, eriodictyol, and dihydrotricetin showed cholesterol-lowering efficacy. [ABSTRACT FROM AUTHOR]

Chlorinated paraffins (CPs) are widely used persistent organic pollutants (POPs). Based on the carbon chain length, CPs can be classified as short-chain (C10-13) CPs (SCCPs), medium-chain (C14-17) CPs (MCCPs), and long-chain (C≥18) CPs (LCCPs). Since SCCPs have been listed as POPs of particular concern by the Stockholm Convention, the production of MCCPs and LCCPs is increased sharply. Therefore, the number of studies focusing on MCCPs and LCCPs has increased recently. Herein, we comprehensively reviewed recent studies on the biological occurrence, bioaccumulation, transmission, and transformation of CPs. CPs are pervasively distributed across biotas and exhibit diverse accumulation properties in different tissues. MCCPs and LCCPs are more abundant than SCCPs in some organisms. The absorption, translocation, and elimination behaviors of CPs directly influence their accumulation in organisms. The maternal transfer is an elimination pathway for CPs and could explain the discrepancy in CPs accumulation in opposite sexes of some organisms. With the establishment of novel screening methods, several transformation products of CPs have been identified in plants, microorganisms, and humans. By comparing the biotransformation pathways of CPs in different organisms, common and unique pathways have been identified in various species, although further studies on the transformation of CPs in humans and other animals are required. This review describes some noteworthy and prospective studies focused on the biological behavior of CPs. The review also derives novel conclusions based on recent studies in this field to provide a comprehensive understanding of the environmental fate of CPs. [ABSTRACT FROM AUTHOR]

Coumarin and its derivatives, presenting in many organisms (plants, fungi, and bacteria), are critical metabolites composed of fused benzene and α-pyrone rings. With unique biological and chemical properties, coumarin derivatives possess great technological potential in the agrochemicals, pharmaceuticals, food, and cosmetic industries. The increasing demand for coumarin derivatives accelerates the research in biological and chemical synthesis to provide stable and scalable sources of coumarins. However, the complex structures and unknown pathways have limited the progress in the biosynthesis of coumarin derivatives. Here, we summarize recent developments and provide a detailed analysis of coumarin derivative biosynthetic pathways in different organisms.

Abstract Biliverdin, a bile pigment hydrolyzed from heme by heme oxygenase (HO), serves multiple functions in the human body, including antioxidant, anti-inflammatory, and immune response inhibitory activities. Biliverdin has great potential as a clinical drug; however, no economic and efficient production method is available currently. Therefore, the production of biliverdin by the biotransformation of exogenous heme using recombinant HO-expressing yeast cells was studied in this research. First, the heme oxygenase-1 gene (HO1) encoding the inducible plastidic isozyme from Arabidopsis thaliana, with the plastid transport peptide sequence removed, was recombined into Pichia pastoris GS115 cells. This resulted in the construction of a recombinant P. pastoris GS115-HO1 strain that expressed active HO1 in the cytoplasm. After that, the concentration of the inducer methanol, the induction culture time, the pH of the medium, and the concentration of sorbitol supplied in the medium were optimized, resulting in a significant improvement in the yield of HO1. Subsequently, the whole cells of GS115-HO1 were employed as catalysts to convert heme chloride (hemin) into biliverdin. The results showed that the yield of biliverdin was 132 mg/L when hemin was added to the culture of GS115-HO1 and incubated for 4 h at 30 °C. The findings of this study have laid a good foundation for future applications of this method for the economical production of biliverdin. Graphical Abstract

A biotransformation system (LSBT) consisting of Lactococcus lactis and Streptococcus lactis was used to eliminate the yeasty odor of eight yeast extracts with different characteristics (FG10, FM88, FM31, KU012, FIG12LS, F58, FIG03 and KA02) with a focus on flavor substances and amino acids. Meanwhile, the applicability and universality of LSBT were evaluated. All yeast extracts had no longer any yeasty flavor after being treated with LSBT, and FG10 and FM88 were provided with a fermented sauce flavor. Producing no indole was found to be one of the key factors for the success of LSBT. At the same time, the lactic acid content of the transformed yeast extract should not be less than 10.00 g/L. The difference of raw materials played an important role in the LSBT. In particular, the deficiency of aspartic acid and excessive accumulation of threonine in raw materials were likely reasons for the unsuccessful conversion of LSBT. Overall, LSBT is applicable to most yeast extracts, but other microbial combination techniques or fermentation conditions need to be explored for specific yeast extracts such as F58, FIG03 and KA02.

Abstract Background Chitinases are widely distributed enzymes that perform the biotransformation of chitin, one of the most abundant polysaccharides on the biosphere, into useful value-added chitooligosaccharides (COS) with a wide variety of biotechnological applications in food, health, and agricultural fields. One of the most important group of enzymes involved in the degradation of chitin comprises the glycoside hydrolase family 18 (GH18), which harbours endo- and exo-enzymes that act synergistically to depolymerize chitin. The secretion of a chitinase activity from the ubiquitous yeast Mestchnikowia pulcherrima and their involvement in the post-harvest biological control of fungal pathogens was previously reported. Results Three new chitinases from M. pulcherrima, MpChit35, MpChit38 and MpChit41, were molecularly characterized and extracellularly expressed in Pichia pastoris to about 91, 90 and 71 mU ml− 1, respectively. The three enzymes hydrolysed colloidal chitin with optimal activity at 45 ºC and pH 4.0-4.5, increased 2-times their activities using 1 mM of Mn2+ and hydrolysed different types of commercial chitosan. The partial separation and characterization of the complex COS mixtures produced from the hydrolysis of chitin and chitosan were achieved by a new anionic chromatography HPAEC-PAD method and mass spectrometry assays. An overview of the predicted structures of these proteins and their catalytic modes of action were also presented. Depicted their high sequence and structural homology, MpChit35 acted as an exo-chitinase producing di-acetyl-chitobiose from chitin while MpChit38 and MpChit41 both acted as endo-chitinases producing tri-acetyl-chitotriose as main final product. Conclusions Three new chitinases from the yeast M. pulcherrima were molecularly characterized and their enzymatic and structural characteristics analysed. These enzymes transformed chitinous materials to fully and partially acetylated COS through different modes of splitting, which make them interesting biocatalysts for deeper structural-function studies on the challenging enzymatic conversion of chitin.

Abstract Citrus plants have diverse methoxyflavonoids including, chrysoeriol, isosakuranetin, and nobiletin. In plants, O-methyltransferases (OMTs) participate in the methylation of a vast array of secondary metabolites, including flavonoids, phenylpropanoids, and alkaloids. To identify functional OMTs involved in the formation of methoxyflavonoids, orange (Citrus sinensis) OMT (CsOMT) genes were retrieved from the Citrus Genome Database. The phylogenetic relationships with functional OMTs suggested that three CsOMTs, CsOMT15, CsOMT16, and CsOMT30, are possible candidates for flavonoid OMTs (FOMTs). These CsOMTs were heterologously expressed in Escherichia coli, and their OMT activity was examined with flavonoid substrates. Of the examined CsOMTs, CsOMT16 catalyzed the regiospecific 3'-O-methylation of flavonoids to the respective 3'-methoxyflavonoids. A kinetic study demonstrated that CsOMT16 accepts diverse flavonoids as a substrate with a comparable preference. The flavonoids eriodictyol, luteolin, and quercetin were efficiently converted to homoeriodictyol, chrysoeriol, and isorhamnetin by CsOMT16-transformed E. coli cells, respectively. These findings suggest that CsOMT16 contributes to the methoxyflavonoid formation in orange and is applicable to the biotechnological production of 3'-methoxyflavonoids.

Current challenges in (eco)toxicology are in understanding the transformation of (reactive) substances, and how transformation affects toxic modes of action. Empirical assessment of transformation products of, practically an infinite number of substances, via experimentation, is impossible. Predicting transformation products for (benchmarking) compounds from conditions, facilitates risk analyses. This study applied calculus to predict transformation products of an important environmental and medicinal/toxicological marker, carbamazepine. As radicals are ubiquitous in humans and the environment, we looked into radical-mediated transformations of carbamazepine as a benchmark. We calculated proportions of their speciation states as function of redox conditions, which we took as pH and O2 concentration, describing transformation via covalent and ionic interactions. Formation of ring-contracted products with neuro-immunological activity is thermodynamically favored under anaerobic conditions and at low pH. Experimentally observed product distributions and toxicities reflect that pattern. Our predictive method may support toxicity predictions for other substances and conditions 'similar' to the current case study via interpolation. This paves the way for a more coherent, effective and easier risk assessment of transformation products.

Biotransformation and biodegradation of estrogenic compounds by bacteria and even fungi have been reported widely, but the role of microalgae in the elimination of estrogens from municipal wastewater treatment plants and their interaction with other microorganisms in wastewater are not clear. This study reported the feasibility of repeatedly removing a mixture of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), each was 100 μg L−1, from primary settled municipal sewage by Selenastrum capricornutum (SC), a ubiquitous microalga, in four exposure cycles, each lasted 7 days, and how they interacted with the microbial consortium in sewage. Mixed estrogen in sewage stimulated the growth of SC, and the indigenous microorganisms in sewage also affected the microalgal growth. The indigenous microorganisms, particularly bacteria, could easily remove E2 (with 99.5% removal), so the role of SC was insignificant. On the contrary, EE2 was difficult to remove by indigenous microorganisms but the removal was significantly enhanced by SC, with almost all spiked EE2 being removed, even at the end of the fourth cycle (with 99.0% removal). These results indicated that SC, together with the indigenous microorganisms in wastewater, could be repeatedly used for simultaneous removal of E2 and EE2 from municipal sewage. HIGHLIGHTS Growth of S. capricornutum (SC) was affected by estrogen and sterilization.; The role of SC to remove E2 was insignificant as indigenous microbes were effective.; The inoculation of SC significantly enhanced the removal of EE2 in sewage.; SC could be repeatedly used to remove synthetic EE2 from sewage.;

ABSTRACTPleurotus ostreatus is an edible fungus with several functional compounds. Previous studies have shown that solid-state fermentation of Phaseolus vulgaris and Avena sativa with P. ostreatus improves their functional properties. Since bread is a highly consumed foodstuff, the objective of this work was to improve its nutritional and functional properties based on P. vulgaris and A. sativa grains biotransformed by P. ostreatus. Results showed that bread made with flour of solid-state fermented grains, provided a higher antioxidant capacity compared to bread made without fermented grains flour. The antioxidant capacity was maintained even after in vitro simulated digestion assays. Bioaccessible protein and fiber content results showed an increase compared to commercial breads. Fermented-flour bread showed lower hardness in its crumb, changed color, and had a good sensory acceptability. This makes these flours potential ingredients in the development of baking goods, making the bread a vehicle for nutrient delivery.

Vanillin is one of the most important flavoring agents worldwide. Currently, consumers' awareness and concern for biovanillin production has been increasing. This study aimed to screen the potential of clove rhizospheric bacteria isolates producing vanillin through a biotransformation process of eugenol and to conduct the preliminary optimization of the biotransformation condition. Twenty-eight bacteria isolates were screened for their capability to transform eugenol into vanillin. BKL 15 isolate, which was identified as Lysinibacillus xylanilyticus, was selected as the highest vanillin producer among the isolates. The optimum molar yield of vanillin produced by the selected isolate was 4.99% (1.11 g/L) after 168 hours of biotransformation process in the medium consisting of TSB (30 g/L), eugenol (24 g/L), yeast extract (20 g/L), and concentration of casamino acid (20 g/L). Throughout the publications we have read, this is the first report of L. xylanolyticus that produces vanillin. [ABSTRACT FROM AUTHOR]

Phytoremediation is a low-cost and sustainable green technology that uses plants to remove organic and inorganic pollutants from aquatic environments. The aim of this study was to investigate the phytoextraction, phytoaccumulation, and phytotransformation of three fluoroquinolones (FQs) (ciprofloxacin [CIP], enrofloxacin [ENF], and levofloxacin [LVF]) by Japanese radish (Raphanus sativus var. longipinnatus) and duckweed (Lemma minor). Determination of FQs and identification of their transformation products (TPs) were performed using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS). Inter-tissue translocation of FQs in Japanese radish tissues depended on their initial concentration in the medium. CIP (IT = 14.4) and ENF (IT = 17.0) accumulated mainly in radish roots, while LVF in leaves (IT = 230.8) at an initial concentration of 10 µg g−1. CIP (2,104 ng g−1) was detected in the highest concentration, followed by ENF (426.3 ng g−1) and LVF (273.3 ng g−1) in the tissues of both plants. FQs' bioaccumulation factors were significantly higher for duckweed (1.490–18.240) than Japanese radish (0.027–0.103). The removal of FQs from water using duckweed was mainly due to their photolysis and hydrolysis than plant sorption. In the screening, analysis detected 29 FQ TPs. The biotransformation pathways of FQs are described in detail, and the factors that influence their formation are indicated. This study has presented the efficiency of fluoroquinolone (FQ) residues phytoextraction from water by two plant species (water duckweed, Japanese radish). The use of two plant species allowed for a holistic study of the FQ phytoremediation process by determining the efficiency of extraction, tissue distribution, bioaccumulation tendency, and biotransformation. The research gap regarding FQ transformation products in the phytoremediation process and the factors determining their formation has been filled. This study indicated that duckweed can be used with great efficiency to purify water from FQ contamination. [ABSTRACT FROM AUTHOR]

Carbon catabolite repression (CCR) is a highly conserved mechanism that regulates carbon source utilization in Streptomyces. CCR has a negative impact on secondary metabolite fermentation, both in industrial and research settings. In this study, CCR was observed in the daunorubicin (DNR)-producing strain Streptomyces coeruleorubidus DM, which was cultivated in high concentration of carbohydrates. Unexpectedly, DM exhibited a high ability for anthraquinone glucuronidation biotransformation under CCR conditions with a maximum bioconversion rate of 95% achieved at pH 6, 30°C for 24 h. The co-utilization of glucose and sucrose resulted in the highest biotransformation rate compared to other carbon source combinations. Three novel anthraquinone glucuronides were obtained, with purpurin-O-glucuronide showing significantly improved water solubility, antioxidant activity, and antibacterial bioactivity. Comparative transcript analysis revealed that glucose and sucrose utilization were significantly upregulated as DM cultivated under CCR condition, which strongly enhance the biosynthetic pathway of the precursors Uridine diphosphate glucuronic acid (UDPGA). Meanwhile, the carbon metabolic flux has significantly enhanced the fatty acid biosynthesis, the exhaust of acetyl coenzyme A may lead to the complete repression of the biosynthesis of DNR, Additionally, the efflux transporter genes were simultaneously downregulated, which may contribute to the anthraquinones intracellular glucuronidation. Overall, our findings demonstrate that utilizing CCR can be a valuable strategy for enhancing the biotransformation efficiency of anthraquinone O-glucuronides by DM. This approach has the potential to improve the bioavailability and therapeutic potential of these compounds, opening up new possibilities for their pharmaceutical applications.

Biomethylation is an effective means of arsenic detoxification by organisms living in aquatic environments. Ciliated protozoa (including Tetrahymena species) play an important role in the biochemical cycles of aquatic ecosystems and have a potential application in arsenic biotransformation. This study compared arsenic tolerance, accumulation, methylation, and efflux in 11 Tetrahymena species. Nineteen arsenite (As(III)) S-adenosylmethionine (SAM) methyltransferase (arsM) genes, of which 12 are new discoveries, were identified, and protein sequences were studied. We then constructed recombinant cell lines based on the Tetrahymena thermophila (T. thermophila) wild-type SB210 strain and expressed each of the 19 arsM genes under the control of the metal-responsive the MTT1 promoter. In the presence of Cd2+ and As(V), expression of the arsM genes in the recombinant cell lines was much higher than in the donor species. Evaluation of the recombinant cell line identified one with ultra-high arsenic methylation enzyme activity, significantly higher arsenic methylation capacity and much faster methylation rate than other reported arsenic methylated organisms, which methylated 89% of arsenic within 6.5 h. It also had an excellent capacity for the arsenic detoxification of lake water containing As(V), 56% of arsenic was methylated at 250 μg/L As(V) in 48 h. This study has made a significant contribution to our knowledge on arsenic metabolism in protozoa and demonstrates the great potential to use Tetrahymena species in the arsenic biotransformation of aquatic environments.

Deca- and dodecalactones are highly desired natural compounds that are essential for creating flavor formulations with fruity, peachy, creamy, and floral notes. Although natural ingredients are preferred by consumers, these lactones cannot be extracted from natural sources. Therefore, the biotechnological processes that produce these compounds in their natural form are crucial for the flavor industry. Here, we report a study on the biotransformation of vegetable oils into natural deca- and dodecalactones. The proposed process is performed one-pot, through the sequential use of three different biotransformation steps, namely the lipase-mediated hydrolysis of the triglycerides, the use of probiotic bacteria for the hydration of the unsaturated fatty acids and the transformation of the obtained hydroxy-fatty acids into lactones derivatives employing Yarrowia lipolytica. By using a specific vegetable oil in combination with a selected bacterial strain, it is possible to obtain a preferred lactone derivative such as γ-dodecalactone, dairy lactone, tuberose lactone, or δ-decalactone in a concentration ranging from 0.9 to 1.5 g/L. Overall, our method is suitable for the industrial production of these lactones as it is easily scalable, it can be performed in only one bioreactor and it makes use of generally recognized as safe (GRAS) microorganisms. [Display omitted] • Transformation of vegetable oils into natural deca- and dodecalactones. • Microbial Hydration of unsaturated fatty acids. • Biotransformation with probiotic bacteria. • Biotechnological production of flavours. [ABSTRACT FROM AUTHOR]

Lathyrane-type diterpenes have a wide range of biological activities. Among them, euphoboetirane A (1) exerts neurogenesis-promoting activity. In order to increase the structural diversity of this type of lathyrane and explore its potential use in neurodegenerative disorders, the biotransformation of 1 by Streptomyces puniceus BC-5GB.11 has been investigated. The strain BC-5GB.11, isolated from surface sediments collected from the intertidal zone of the inner Bay of Cadiz, was identified as Streptomyces puniceus, as determined by phylogenetic analysis using 16S rRNA gene sequence. Biotransformation of 1 by BC-5GB.11 afforded five products (3–7), all of which were reported here for the first time. The main biotransformation pathways involved regioselective oxidation at non-activated carbons (3–5) and isomerization of the ∆12,13 double bond (6). In addition, a cyclopropane-rearranged compound was found (7). The structures of all compounds were elucidated on the basis of extensive NMR and HRESIMS spectroscopic studies. [ABSTRACT FROM AUTHOR]