Recent Progress on Biocatalysis and Biotransformations in Ionic Liquids

Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liquids or aqueous-ionic liquid biphasic systems. Up to date, there have been many reports on enzyme-exhibited features and enzyme-mediated reactions in ionic liquids. In many cases, remarkable results with respect to yield, catalytic activity, stability and (enantio-, regio-) selectivity were obtained in ionic liquids in comparison with those observed in conventional media. Accordingly, ionic liquids provide new possibilities for the application of new type of solvent in biocatalytic reactions.

Metabolomic studies in the inborn error of metabolism alkaptonuria reveal new biotransformations in tyrosine metabolism

Alkaptonuria (AKU) is an inherited disorder of tyrosine metabolism caused by lack of active enzyme homogentisate 1,2-dioxygenase (HGD). The primary consequence of HGD deficiency is increased circulating homogentisic acid (HGA), the main agent in the pathology of AKU disease. Here we report the first metabolomic analysis of AKU homozygous Hgd knockout (Hgd−/−) mice to model the wider metabolic effects of Hgd deletion and the implication for AKU in humans. Untargeted metabolic profiling was performed on urine from Hgd−/− AKU (n = 15) and Hgd+/− non-AKU control (n = 14) mice by liquid chromatography high-resolution time-of-flight mass spectrometry (Experiment 1). The metabolites showing alteration in Hgd−/− were further investigated in AKU mice (n = 18) and patients from the UK National AKU Centre (n = 25) at baseline and after treatment with the HGA-lowering agent nitisinone (Experiment 2). A metabolic flux experiment was carried out after administration of 13C-labelled HGA to Hgd−/−(n = 4) and Hgd+/−(n = 4) mice (Experiment 3) to confirm direct association with HGA. Hgd−/− mice showed the expected increase in HGA, together with unexpected alterations in tyrosine, purine and TCA-cycle pathways. Metabolites with the greatest abundance increases in Hgd−/− were HGA and previously unreported sulfate and glucuronide HGA conjugates, these were decreased in mice and patients on nitisinone and shown to be products from HGA by the 13C-labelled HGA tracer. Our findings reveal that increased HGA in AKU undergoes further metabolism by mainly phase II biotransformations. The data advance our understanding of overall tyrosine metabolism, demonstrating how specific metabolic conditions can elucidate hitherto undiscovered pathways in biochemistry and metabolism.

A.Flavus Mediated Biotransformations for the Syntheses of Active A-oxyfunctionalized Compounds

1 Results Biotransformations are enzyme- and whole cell-catalysed conversions of non-natural substrates to products.They are important tools in organic synthesis,especially for the syntheses of chiral molecules,where the reactions catalysed may be asymmetric syntheses or the resolution of racemates.The main advantages associated with the use of single enantiomer compounds are increased specificity and the avoidance of adverse side effects[1].Whole cell reactions are advantegous over enzyme-catalyzed rea...

Biotransformation of Gastrodin by Cell Suspension Cultures of Catharanthus roseus

应用长春花 (Catharanthusroseus (L .)G .Don)悬浮细胞培养体系对天麻素进行了生物转化反应研究。经过8d培养形成一个转化产物 ,应用光谱方法鉴定转化产物的结构为对羟基苯甲醇 ,为天麻素水解后形成的甙元。

Biotransformation of Gastrodin by Mucor spinosus

Microbial transformation of gastrodin by Mucor spinosus strain 3.3450, resulted in a product with a transformation rate close to 100 per cent. This product was identified as p-hydroxy benzyl alcohol on the basis of its 1H, 13C NMR and EI-MS spectral data. It could be inferred that the enzyme responsible for the biotransforma-tion reaction was a kind of extracellular and constitutive enzyme since the transformation reaction of the substrate could be carried out in cell free extracts of the fermentation broth of the Mucor spinosus.

RELATIONSHIP BETWEEN GROWTH AND MORPHOLOGY OF METARRHIZIUM ANISOPLIAE IN BIOTRANSFORMATION OF STEROID

The fermentation with mold metarrhizium anisopliae has been carried out to determine the relationship between mycelial morphology and growth.Like the biomass concentration,the mycelial morphology seems to be coupled to growth phases:the fractal dimension,a feature calculated from the morphological images,increases during the late lag phase and the early exponential phase,and culminates at a value near 2.4 at half of the exponential phase.This can be attributed to the marked change of rough and smooth pellet proportions during growth and the change can be well expressed by the fractal analysis of mycelial morphology.The mycelial morphology is also strongly related to the biotransformation activity:a mycelial sample was withdrawn from the culture to use for fractal analysis before the steroid substrate (16α,17α epoxy 4 pregnene 3,20 dione) was added;the higher fractal dimension corresponds to the higher conversion rate of steroid biotransformation.And the maximum of fractal dimension appeared prior to the maximum of biomass concentration.It is therefore possible to utilize the fractal dimension curve to supervise the fermentation process more timely and availably than to use the conventional biomass curve to do.

Study on Anti-oxidation and Inhibitory Effect on Nonenzymatic Glycation Reaction of Fermentation Extract from Biotransformation of Ginkgo biloba L. (EGB) by Hericium erinaceus

[ Objective] In order to study the anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of EGB fermentation extraction biotransformed by Hericium erinaceus. [ Method ] The free radical scavenging ability and reducing capacity of DPPH as well as inhibitory rate of nonenzymatic glycation reaction were measured targets for comparing changes of anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of fermentation lyophilizer and fermentation extraction before and after EGB fermention adsorbed by AB-8 macroporous resin. The EGB fermention was biotransformed by Hericium erinaceus. [ Result ] After adsorbed by AB-8 macroporous resin, the bioactive matters were concentrated and separated. The free radical scavenging rate, reducing capacity and inhibitory rate of nonenzymatic glycation reaction were increased significantly after adsorbed by AB-8 macroporous resin. [ Conclusion] AB-8 macroporous resin could be used for preliminary concentration of EGB fermentation which was biotransformed by Hericium erinaceus.

Biotransformation of Artemisinin by Hairy Root Cultures of Rheum palmatum L.

The biotransformation of artemisinin by hairy root cultures ofRheum palmatum L. was investigated for the first time. The main product, deoxyartemisinin, was isolated and characterized on the basis of its spectral data.

Status quo of soil petroleum contamination and evolution of bioremediation

Along with the rapid development of oil industries internationally,petroleum prospecting and exploitation activities are growing intensively.Especially in China,with the fastest economic growth in the world and shortage of petroleum resources,we are leading the practices of petroleum deep exploitation.Obviously,the risk of damage to the natural environment from these activities is high.Oil contamination in soils and groundwater is becoming a big issue along with pesticide pollution,which makes organic pollution prevention and control （OPPC） much more complex.In this paper,based on recent research on oil-contaminated soil at home and abroad,we make comments on the remediation technologies for polluted soil,emphasizing bioremediation techniques and degradation mechanisms in order to push forward research into bound organic pollution prevention and control （OPPC）,especially in China.

Technologies of Seperating and Exactly 11-α-Hydroxy-Canerenone from Biotransformation Broth

[Objective] The aim was to investigate the effect of four extraction meth- ods on extraction ratio of 11-α-Hydroxy-Canerenone from biotransformation broth. [Method] Previous reported method, soaking, elution method and homogenate meth- ods were used. [Result] Results showed that more than 90% of the biotransformed 11-α-Hydroxy-Canerenone existed in the broth supernatant and mycelia surface. Elu- tion and soaking methods were effective for 11-α-Hydroxy-Canerenone extraction. Extraction yields of 96.0% and 98.8% were obtained by eluting with 400 ml of ethy- lacetate and soaking with ethylacetate for 90 min, respectively. [Conelusion] The method is simple and efficient, showing industrial application potential.

Role of baicalin as a potential therapeutic agent in hepatobiliary and gastrointestinal disorders:A review

Baicalin is a natural bioactive compound derived from Scutellaria baicalensis,which is extensively used in traditional Chinese medicine.A literature survey demonstrated the broad spectrum of health benefits of baicalin such as antioxidant,anticancer,anti-inflammatory,antimicrobial,cardio-protective,hepatoprotective,renal protective,and neuroprotective properties.Baicalin is hydrolyzed to its metabolite baicalein by the action of gut microbiota,which is further reconverted to baicalin via phase 2 metabolism in the liver.Many studies have suggested that baicalin exhibits therapeutic potential against several types of hepatic disorders including hepatic fibrosis,xenobiotic-induced liver injury,fatty liver disease,viral hepatitis,cholestasis,ulcerative colitis,hepatocellular and colorectal cancer.During in vitro and in vivo examinations,it has been observed that baicalin showed a protective role against liver and gut-associated abnormalities by modifying several signaling pathways such as nuclear factor-kappa B,transforming growth factor beta 1/SMAD3,sirtuin 1,p38/mitogen-activated protein kinase/Janus kinase,and calcium/calmodulin-dependent protein kinase kinaseβ/adenosine monophosphate-activated protein kinase/acetyl-coenzyme A carboxylase pathways.Furthermore,baicalin also regulates the expression of fibrotic genes such as smooth muscle actin,connective tissue growth factor,β-catenin,and inflammatory cytokines such as interferon gamma,interleukin-6(IL-6),tumor necrosis factor-alpha,and IL-1β,and attenuates the production of apoptotic proteins such as caspase-3,caspase-9 and B-cell lymphoma 2.However,due to its low solubility and poor bioavailability,widespread therapeutic applications of baicalin still remain a challenge.This review summarized the hepatic and gastrointestinal protective attributes of baicalin with an emphasis on the molecular mechanisms that regulate the interaction of baicalin with the gut microbiota.

Degradation of lignite model compounds by the action of white rot fungi

Three compounds modeled on the lignite structure were chosen for experimental degradation by different fungi strains. Culture conditions and extracellular enzyme activities were optimized. The growth curves of the strains were determined to study mycelium dry weight and protein content changes. Gas chromatography and infrared spectroscopy were used to detect changes of functional groups before and after the action of the fungi on the model compounds. Possible decomposition products and degrada-tion mechanisms were proposed. The research findings show that C. Versicolor and Golden Mushroom can grow in presence of the model compounds. The optimum culture conditions were a pH of 6.0, a carbon-nitrogen ratio of five and a Tween-80 concentration of 0.1%. Newly produced substances were found by gas chromatography. Infrared analysis showed that the model compounds degraded under the action of the microorganisms.

Biotransformation of aesculin by human gut bacteria and identification of its metabolites in rat urine

AIM： To observe the biotransformation process of a Chinese compound, aesculin, by human gut bacteria, and to identify its metabolites in rat urine.METHODS： Representative human gut bacteria were collected from 20 healthy volunteers, and then utilized in vitro to biotransform aesculin under anaerobic conditions. At 0, 2, 4, 8, 12, 16, 24, 48 and 72 h postincubation, 10 mL of culture medium was collected. Metabolites of aesculin were extracted 3 × from rat urine with methanol and analyzed by HPLC. For in vivo metabolite analysis, aesculetin （100 mg/kg） was administered to rats via stomach gavage, rat urine was collected from 6 to 48 h post-administration, and metabolite analysis was performed by LC/ESI-MS and MS/MS in the positive and negative modes.RESULTS： Human gut bacteria could completely convert aesculin into aesculetin in vitro. The biotransformation process occurred from 8 to 24 h post-incubation, with its highest activity was seen from 8 to 12 h. The in vitro process was much slower than the in vivo process. In contrast to the in vitro model, six aesculetin metabolites were identified in rat urine, including 6-hydroxy-7-glucocoumarin（M1）, 6-hydroxy-7-sulf-coumarin （M2）, 6, 7-digluco-coumarin （M3）, 6-glc-7-gluco-coumarin （M4）, 6-O-methyl-7-gluco-coumarin （MS） and 6-O-methyl-7- sulf-coumarin （M6）. Of which, M2 and M6 were novel metabolites.CONCLUSION： Aesculin can be transferred into aesculetin by human gut bacteria and is further modified by the host in vivo. The diverse metabolites of aesculin may explain its pleiotropic pharmaceutical effects.

Effects of benzo(a)pyrene exposure on the antioxidant enzyme activity of scallop Chlamys farreri

Scallop Chlamys farreri was exposed to different concentrations of benzo(a)pyrene (BaP) (0.5 μg/L, 1.0 μg/L, 10.0 μg/L and 50.0 μg/L) for 30 days in seawater. The 7-ethoxyresorufin O-deethylase (EROD) activity was significantly induced, and increased with the increasing BaP concentration. The glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), Glutathione peroxidase (GPx) activities increased in short time at low concentration of BaP, and was significantly depressed at high concentrations. Scallop gill was more sensitive to BaP than the digestive gland, and the digestive gland was the main tissue to deal with oxyradicals. The contents of malondialdehyde (MDA) increased with the exposure time and there was a positive correlation (concentration-effect) between the MDA content and the concentration of BaP. The biomarkers determined in this experiment had important roles in detoxification, and showed great potential as biomarkers for oxidative stress. Controlled laboratory experiments designed to simulate field exposure scenarios are particularly useful in ascertaining biomarkers suitable for use with complex contaminant mixtures in the marine environment.

Early metabolism evaluation making traditional Chinese medicine effective and safe therapeutics

Increasing attention is being paid to the scientific evaluation of traditional Chinese medicine （TCM）. As many TCMs are capable of biotransformation in the gastrointestinal tract, attention to biotransforrnation of TCM in the gastrointestinal tract may lead to discovery of the active components and active mechanisms. In this article, we review reports that host metabolic enzymes and intestinal bacteria may be responsible for the metabolism of TCM. Good understanding of the in vivo course of TCM will help us to know how to conduct metabolism evaluation of TCM by using in vitro human-derived system. This evaluation system will create new views on TCM as effective and safe therapeutic agents.

BIOTRANSFORMATION OF 2α，5α，10β，14β－TETRA－ACETOXY－4（20），11－TAXADIENE BY THE FUNGIJS CUNNINGHAMELLA ECHINULATA

?5α,10β,14β-Tetra-acctoxy-4(20).11-taxadicne (1) could be regioselectively transfonnedinto 6α 10β-dihydroxy-2α,5α,14β-triacetoxy-4(20). 11- taxadiene (2) by Cunninghamella echinnlata infair yield. 6βM.10β-Dihydroxy-2α,5α,14β-triacet 11-taxadienc (3). 10β-hydroxy-2α,5α,14β-triacetoxy-4(20).11-taxadiene (4), 10 β-hyboxy-4β,20-epoxy -2α,5α,14β-triacetoxy- tax - 11- ene (5)asminor prpducts were also isolated

Transformation of berberine to its demethylated metabolites by the CYP51 enzyme in the gut microbiota

Berberine(BBR)is an isoquinoline alkaloid extracted from Coptis chinensis that improves diabetes,hyperlipidemia and inflammation.Due to the low oral bioavailability of BBR,its mechanism of action is closely related to the gut microbiota.This study focused on the CYP51 enzyme of intestinal bacteria to elucidate a new mechanism of BBR transformation by demethylation in the gut microbiota through multiple analytical techniques.First,the docking of BBR and CYP51 was performed;then,the pharmacokinetics of BBR was determined in ICR mice in vivo,and the metabolism of BBR in the liver,kidney,gut microbiota and single bacterial strains was examined in vitro.Moreover,16S rRNA analysis of ICR mouse feces indicated the relationship between BBR and the gut microbiota.Finally,recombinant E.coli containing cyp51 gene was constructed and the CYP51 enzyme lysate was induced to express.The metabolic characteristics of BBR were analyzed in the CYP51 enzyme lysate system.The results showed that CYP51 in the gut microbiota could bind stably with BBR,and the addition of voriconazole(a specific inhibitor of CYP51)slowed down the metabolism of BBR,which prevented the production of the demethylated metabolites thalifendine and berberrubine.This study demonstrated that CYP51 promoted the demethylation of BBR and enhanced its intestinal absorption,providing a new method for studying the metabolic transformation mechanism of isoquinoline alkaloids in vivo.

Identification and Mutagenesis of a New Isolated Strain Bacillus sp.B26 for Producing （R）-α-Hydroxyphenylacetic Acid

A bacterium strain B26 capable of producing(R)-α-hydroxyphenylacetic acid [(R)-HPA](yield,47.5%;enantiomeric excess,99.1%) from phenylglyoxylic acid(PGA) with high optical purity was isolated and identified as Bacillus sp.B26 by 16S rDNA(ribosomal DNA) sequencing.Phylogenic analysis showed that the strain was most similar to Bacillus sp.enrichment culture clone SYW5(FJ601635.1) and Bacillus cereus strain FM-4(EU794727.1).Efforts were made to further improve HPA-production and PGA-tolerance by UV irradiation and UV-LiCl cooperative mutagenesis.Among viable mutants,B.sp.UV-38 and B.sp.ULi-11 exhibited better productivities than the wild type.Comparisons of HPA production and time course among wild strain and two mutants showed that B.sp.ULi-11 was more competent than B.sp.UV-38.HPA production was increased by 39.1% with B.sp.ULi-11(yield,65.4%) compared to that with B.sp.B26(yield,47.0%) when cultured in fermentation broth(pH 7.2) at 32℃ with an agitation speed of 180 r·min-1 and PGA final concentration of 15 mmol·L-1 for 25 h.

One new bufadienolide biotransformed from cinobufagin by Cunninghamella elegans

Cunninghamella elegans has been employed for the biotransformation of cinobufagin （1） to afford one metabolites. The structure of the transformation product has been characterized as 7β,12β-dihydroxylcinobufagin （2）. Product 2 is a new compound. In vitro cytotoxic activities of the biotransformation product and the substrate-cinobufagin have been assayed against HeLa; they all showed cytotoxic activities.

A Taxatetraene from Microbial Transformation of Sinenxan A

Sinenxan A [2α, 5α, 10β, 14β-tetraacetoxytaxa-4(20), 11-diene, 1] was biotransformed by a filamentous fungus, Aspergillus niger JCM 5546, and an unusual taxatetraene [2α, 5α-acetoxytaxa-4(20), 10(11), 12(18), 13(14)-tetraene, 2], together with two known products, 10β-deacetyl sinenxan A (3) and 10β, 14β-dideacetyl sinenxan A (4) were produced.