Biotransformation of (+)limonene and (-)piperitone by yeasts and yeast-like fungi

Arxula adeninivorans and Yarrowia lipolytica converted (+)limonene to perillic acid (0.06 and 1.0 g/l; yield 3% and 50%) and (-)piperitone to 7-hydroxy-piperitone (0.06 and 0.04 g/l; yield 12% and 8%). Two unclassified strains of the basidiomycetes, Trichosporon, transformed (+)limonene to isopiperitenone (0.05 and 0.4 g/l; yield 2% and 20%) and trans-1,2-dihydroxy-limonene (0.6 g/l; yield 30%) and (-)piperitone to trans-6-hydroxy-piperitone (0.1 and 0.2 g/l; yield 20% and 40%) and 2-isopropyl-5-methyl-hydroquinone (0.8 g/l; yield 16%).     

Biotransformation of limonene by Pseudomonas putida

From a study of three fungal and 15 bacterial strains, it was observed that Pseudomonas putida MTCC 1072 oxidized limonene with the highest efficiency of. Fermentation of limonene by P. putida MTCC 1072 was conducted for 120 h at 30 degrees C at a fixed pH of 5.0. Major bioconversion products were isolated and characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, and by elemental analysis. The bioconversion products were identified as perillyl alcohol and p-menth-1-ene-6,8-diol, and under optimum conditions the yields were 36% and 44%, respectively (a rate kinetic model indicated corresponding limiting yields of 44% and 56%). No further degradation of the products was observed using this bacteria.     

Degradation of PCBs by white rot fungi,methylotrophic and hydrocarbon utilizing yeasts and bacteria

Summary Of the white rot fungi tested, two strains alone and other three in combination with specific yeasts or bacteria degraded PCBs in polluted soil within interval 20–30%. When all organisms were applied together PCB degradation achieved was about 50%.     

Biotransformation of N-acetylphenothiazine by fungi

Cultures of the fungi Aspergillus niger, Cunninghamella verticillata, and Penicillium simplicissimum, grown in a sucrose/peptone medium, transformed N-acetylphenothiazine to N-acetylphenothiazine sulfoxide (from 13% to 28% of the total) and phenothiazine sulfoxide (from 5% to 27%). Phenothiazin-3-one (4%) and phenothiazine N-glucoside (4%) were also produced by C. verticillata. The probable intermediate, phenothiazine, was detected only in cultures of P. simplicissimum (6%). Received: 15 January 1999 / Received revision: 7 May 1999 / Accepted: 21 May 1999     

Biotransformation of albendazole by fungi

Twenty-five fungal cultures were screened for their ability to transform the anthelmintic drug albendazole. A filamentous fungi Cunninghamella blakesleeana transformed albendazole to three metabolites in significant quantities. The transformation of albendazole was identified by HPLC. Based on the LC-MS-MS data, two metabolites were predicted to be albendazole sulfoxide and albendazole sulfone, the major mammalian metabolites reported previously. A new N-methylated metabolite of albendazole sulfoxide was also produced, where the methylation took place on the N-atom of the imidazole ring system. A temperature of 30°C, pH of 8 and high substrate concentrations produced highest transformation of albendazole. Among the various concentrations studied, 2% w/v of glucose produced highest transformation. The results reveal that the microbial model can be used to produce large quantities of mammalian metabolites.     

Uniform categorization of biocommunication in bacteria, fungi and plants

This article describes a coherent biocommunication categorization for the kingdoms of bacteria, fungi and plants. The investigation further shows that, besides biotic sign use in trans-, inter- and intraorganismic communication processes, a common trait is interpretation of abiotic influences as indicators to generate an appropriate adaptive behaviour. Far from being mechanistic interactions, communication processes within organisms and between organisms are sign-mediated interactions. Sign-mediated interactions are the precondition for every cooperation and coordination between at least two biological agents such as cells, tissues, organs and organisms. Signs of biocommunicative processes are chemical molecules in most cases. The signs that are used in a great variety of signaling processes follow syntactic (combinatorial), pragmatic (context-dependent) and semantic (content-specific) rules. These three levels of semiotic rules are helpful tools to investigate communication processes throughout all organismic kingdoms. It is not the aim to present the latest empirical data concerning communication in these three kingdoms but to present a unifying perspective that is able to interconnect transdisciplinary research on bacteria, fungi and plants.     

Biotransformation of 6,7-epoxygeraniol by fungi

The biotransformation of 6,7-epoxygeraniol by resting cells of selected fungi was investigated. The main product obtained from the transformation in Rhodotorula glutinis and R. marina cultures was 6,7-epoxynerol (5–48% of chloroform extracts), whereas Saccharomyces cerevisiae, Candida parapsilosis and C. kefyr reduced this substrate to 6,7-epoxycitronellol (30–33% of chloroform extracts). Cultures of Yarrowia lipolytica, Botrytis cinerea and S. cerevisiae promoted the cyclisation of 6,7-epoxygeraniol to 2-methyl-2-(2-hydroxyethyl)-5-(2-hydroxyprop-2-yl)tetrahydrofuran (11–99% of chloroform extracts). The biotransformation of 6,7-epoxynerol was also investigated. However, none of the tested micro-organisms converted this compound.     

Biotransformation of betulinic and betulonic acids by fungi

Betulinic acid (1), a triterpenoid found in many plant species, has attracted attention due to its important pharmacological properties, such as anti-cancer and anti-HIV activities. The closely related, betulonic acid (2) also has similar properties. In order to obtain derivatives potentially useful for detailed pharmacological studies, both compounds were submitted to incubations with selected microorganisms. In this work, both were individually metabolized by the fungi Arthrobotrys, Chaetophoma and Dematium, isolated from the bark of Platanus orientalis as well as with Colletotrichum, obtained from corn leaves; such fungal transformations are quite rare in the scientific literature. Biotransformations with Arthrobotrys converted betulonic acid (2) into 3-oxo-7beta-hydroxylup-20(29)-en-28-oic acid (3), 3-oxo-7beta,15alpha-dihydroxylup-20(29)-en-28-oic acid (4) and 3-oxo-7beta,30-dihydroxylup-20(29)-en-28-oic acid (5); Colletotrichum converted betulinic acid (1) into 3-oxo-15alpha-hydroxylup-20(29)-en-28-oic (6) acid whereas betulonic acid (2) was converted into the same product and 3-oxo-7beta,15alpha-dihydroxylup-20(29)-en-28-oic acid (4); Chaetophoma converted betulonic acid (2) into 3-oxo-25-hydroxylup-20(29)-en-28-oic acid (7) and both Chaetophoma and Dematium converted betulinic acid (1) into betulonic acid (2). Those fungi, therefore, are useful for mild, selective oxidations of lupane substrates at positions C-3, C-7, C-15, C-25 and C-30.     

Computational analysis of the fructosyltransferase enzymes in plants, fungi and bacteria

Fructosyltransferases (FTases) are enzymes produced by plants, fungi, and bacteria, which are responsible for the synthesis of fructooligosaccharides. In this study, we conducted a computational analysis of reported sequences for FTase from a diverse source of organisms, such as plants, fungi, and bacteria. Ninety-one proteins sequences were obtained; all belonging to the glycoside hydrolase 32 (GH32) and 68 (GH68) families. The sequences were grouped in seven clades, five for plants, one for fungi, and one for bacteria. Our findings suggest that FTases from fungi and bacteria likely evolved from dicotyledonous FTases. The analysis of catalytic domains A, D and E, which contain the amino acids involved in the catalytic binding site, allowed the identification of clade-specific conserved characteristics. The analysis of sequence motifs involved in donor/acceptor molecule affinity showed that additional sequences could be responsible for donor/acceptor molecule affinity. The correlation of this large set of FTases allowed to identify additional features that might be used for the identification and classification of new FTases, and to improve the understanding of these valuable enzymes.     

Biotransformation of hop aroma terpenoids by ale and lager yeasts

Terpenoids are important natural flavour compounds, which are introduced to beer via hopping. It has been shown recently that yeasts are able to biotransform some monoterpene alcohols. As a first step towards examining whether yeasts are capable of altering hop terpenoids during the brewing of beer, we investigated whether they were transformed when an ale and lager yeast were cultured in the presence of a commercially available syrup. Both yeasts transformed the monoterpene alcohols geraniol and linalool. The lager yeast also produced acetate esters of geraniol and citronellol. The major terpenoids of hop oil, however, were not biotransformed. Oxygenated terpenoids persisted much longer than the alkenes.     

Biotransformation of industrial tannins by filamentous fungi

Tannins are secondary metabolites that are widely distributed in the plant kingdom. They act as growth inhibitors for many microorganisms: they are released upon microbial attack, helping to fight infection in plant tissues. Extraction of tannins from plants is an active industrial sector with several applications, including oenology, animal feeding, mining, the chemical industry, and, in particular, the tanning industry. However, tannins are also considered very recalcitrant pollutants in wastewater of diverse origin. The ability to grow on plant substrates rich in tannins and on industrial tannin preparations is usually considered typical of some species of fungi. These organisms are able to tolerate the toxicity of tannins thanks to the production of enzymes that transform or degrade these substrates, mainly through hydrolysis and oxidation. Filamentous fungi capable of degrading tannins could have a strong environmental impact as bioremediation agents, in particular in the treatment of tanning wastewaters.

     

Biotransformation of cycloalkenones by fungi Baeyer-Villiger oxidation of bicycloheptenone by dematiaceous fungi

Summary The biotransformation by ring expansion of a bicyclo [3.2.0]-alkenone has been demonstrated in 29 species of dematiaceous fungi. One of these biocatalysts,Curvularia lunata NRRL 2380 has been shown to produce synthetically-important chiral lactones in high yields.     

Mechanistic aspects in the biogenic synthesis of extracellular metal nanoparticles by peptides,bacteria, fungi,and plants

Metal nanoparticles have been studied and applied in many areas including the biomedical, agricultural, electronic fields, etc. Several products of colloidal silver are already on the market. Research on new, eco-friendly and cheaper methods has been initiated. Biological production of metal nanoparticles has been studied by many researchers due to the convenience of the method that produces small particles stabilized by protein. However, the mechanism involved in this production has not yet been elucidated although hypothetical mechanisms have been proposed in the literature. Thus, this review discusses the various mechanisms provided for the biological synthesis of metal nanoparticles by peptides, bacteria, fungi, and plants. One thing that is clear is that the mechanistic aspects in some of the biological systems need more detailed studies.     

Flocculation and coflocculation of bacteria by yeasts

Biotransformations in natural environments frequently involve interactions between microorganisms. Although there are many reports on the interactions between bacteria, interactions between yeasts and bacteria have not been extensively studied. Previously we reported on the flocculation and coflocculation of Pediococcus damnosus by Saccharomyces cerevisiae. Now we report that several other yeasts, such as Candida utilis, Dekkera bruxellensis, Hanseniaspora guilliermondii, Kloeckera apiculata, and Schizosaccharomyces pombe, induce flocculation with several industrially or medically relevant bacteria, including Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus. Candida utilis was one of the best flocculation inducers. The results are discussed with respect to interactions between yeasts and bacteria and their applications in industry and medicine.     

Biotransformation of biarylic compounds by yeasts of the genus trichosporon

The biotransformation of biphenyl, dibenzofuran, and diphenyl ether by 24 strains belonging to 18 species of the genus Trichosporon was investigated to assess the taxonomic relevance of this property at species and genus level. With the exceptions of T. brassicae and T. porosum CBS 2040, all other strains were able to transform the parent compounds to monohydroxylated intermediates. A second hydroxylation on the same aromatic ring was carried out by fewer strains and depended on the substrate. It appears that this step is the rate-limiting one in the biotransformation of the biarylic compounds tested. Ring fission of dihydroxylated derivatives of biphenyl was observed within 12 species. The aromatic ring system of dihydroxylated dibenzofuran was cleaved by strains of 5 species, while strains of 13 species were able to cleave the aromatic ring system of dihydroxylated diphenyl ether. Only 4 strains out of 18 species were able to cleave the aromatic ring system of all three parent compounds. These most active yeasts belong to the species T. coremiiforme, T. montevideense, T. mucoides, and T. sporotrichoides. In addition, strains of the species Cryptococcus curvatus and Cryptococcus humicola, closely related to the genus Trichosporon, were tested in parallel.     

Regulatory mechanisms of β-glucan synthases in bacteria, fungi, and plants

The evidence accumulated to date indicates that 1,3-β-glucan synthase (EC 2.3.1.12) and 1,4-β-glucan synthase (EC 2.4.1.12) are regulated by different effectors. Further that the same synthase has different effectors, depending upon its presence in green plants, fungi, and bacteria. Synthases from plants require divalent cations and β-linked glucosides whereas fungal enzymes require neither cations nor β-glucosides, but most require nucleoside triphosphates for activation. Two endogenous effectors have been characterized and shown to produce activation in vitro. One is 3',5'-cyclic diguanylic acid that is the activator of cellulose synthase in bacteria. The other is a β-linked glucosyl dioleoyl diglyceride from mung bean, capable of activating synthases that produce both β-(1–3) and β-(1–4) products. The results of product analysis of the β-linked glucoside activated reaction suggest that the synthesis of (1–3) and (1–4) glucosyl linkages may share a common enzyme in plants. All synthases utilize uridine 5'-diphosphoglucose (UDPG) and are associated with the plasma membrane. Efforts to solubilize the synthases from cellular fractions enriched in plasma membranes have been generally successful. The purification of the soluble enzymes, however, remains a major obstacle to the full understanding of their regulation.     

Convergence in the biosynthesis of acetogenic natural products from plants,fungi, and bacteria

This review deals with polyketides to which nature has developed different biosynthetic pathways in the course of evolution. The anthraquinone chrysophanol is the first example of an acetogenic natural product that is, in an organism-specific manner, formed via more than one polyketide folding mode: In eukaryotes, like e.g., in fungi, in higher plants, and in insects, it is synthesized via folding mode F, while in prokaryotes it originates through mode S. It has, more recently, even been found to be synthesized by a third pathway, named mode S′. Thus, chrysophanol is the first polyketide synthase product that originates through a divergent–convergent biosynthesis (depending on the respective producing organisms). A second example of a striking biosynthetic convergence is the isoquinoline alkaloids. While all as yet investigated representatives of this large family of plant-derived metabolites (more than 2500 known representatives!) are formed from aromatic amino acids, the biosynthetic origin of naphthylisoquinoline alkaloids like dioncophylline A is unprecedented in following a route to isoquinolines in plants: we have shown that such naphthylisoquinolines represent the as yet only known polyketidic di- and tetrahydroisoquinolines, originating from acetate and malonate units, exclusively. Both molecular halves, the isoquinoline part and the naphthalene portion, are even synthesized from a joint polyketide precursor, the first proven case of the F-type folding mode in higher plants. The biosynthetic origins of the natural products presented in this paper were elucidated by feeding ¹³C₂-labeled acetate (or advanced precursors) to the respective producing organisms, with subsequent NMR analysis of their ¹³C₂ incorporation patterns using the potent cryoprobe methodology, thus making the full polyketide folding pattern visible.     

Biotransformation of benzothiophene by isopropylbenzene-degrading bacteria.

Isopropylbenzene-degrading bacteria, including Pseudomonas putida RE204, transform benzothiophene to a mixture of compounds. Induced strain RE204 and a number of its Tn5 mutant derivatives were used to accumulate these compounds and their precursors from benzothiophene. These metabolites were subsequently identified by 1H and 13C nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. When strain RE204 was incubated with benzothiophene, it produced a bright yellow compound, identified as trans-4-[3-hydroxy-2-thienyl]-2-oxobut-3-enoate, formed by the rearrangement of cis-4-(3-keto-2,3-dihydrothienyl)-2-hydroxybuta-2,4-dieno ate, the product of 3-isopropylcatechol-2,3-dioxygenase-catalyzed ring cleavage of 4,5-dihydroxybenzothiophene, as well as 2-mercaptophenylglyoxalate and 2'-mercaptomandelaldehyde. A dihydrodiol dehydrogenase-deficient mutant, strain RE213, converted benzothiophene to cis-4,5-dihydroxy-4,5-dihydrobenzothiophene and 2'-mercaptomandelaldehyde; neither trans-4-[3-hydroxy-2-thienyl]-2-oxobut-3-enoate nor 2-mercaptophenylglyoxalate was detected. Cell extracts of strain RE204 catalyzed the conversion of cis-4,5-dihydroxy-4,5-dihydrobenzothiophene to trans-4-[3-hydroxy-2-thienyl]-2-oxobut-3-enoate in the presence of NAD+. Under the same conditions, extracts of the 3-isopropylcatechol-2,3-dioxygenase-deficient mutant RE215 acted on cis-4,5-dihydroxy-4,5-dihydrobenzothiophene, forming 4,5-dihydroxybenzothiophene. These data indicate that oxidation of benzothiophene by strain RE204 is initiated at either ring. Transformation initiated at the 4,5 position on the benzene ring proceeds by three enzyme-catalyzed reactions through ring cleavage. The sequence of events that occurs following attack at the 2,3 position of the thiophene ring is less clear, but it is proposed that 2,3 dioxygenation yields a product that is both a cis-dihydrodiol and a thiohemiacetal, which as a result of this structure undergoes two competing reactions: either spontaneous opening of the ring, yielding 2'-mercaptomandelaldehyde, or oxidation by the dihydrodiol dehydrogenase to another thiohemiacetal, 2-hydroxy-3-oxo-2,3-dihydrobenzothiophene, which is not a substrate for the ring cleavage dioxygenase but which spontaneously opens to form 2-mercaptophenylglyoxaldehyde and subsequently 2-mercaptophenylglyoxalate. The yellow product, trans-4-[3-hydroxy-2-thienyl]-2-oxobut-3-enoate, is a structural analog of trans-o-hydroxybenzylidenepyruvate, an intermediate of the naphthalene catabolic pathway; extracts of recombinant bacteria containing trans-o-hydroxybenzylidenepyruvate hydratase-aldolase catalyzed the conversion of trans-4-[3-hydroxy-2-thienyl]-2-oxobut-3-enoate to 3-hydroxythiophene-2-carboxaldehyde, which could then be further acted on, in the presence of NAD+, by extracts of recombinant bacteria containing the subsequent enzyme of the naphthalene pathway, salicylaldehyde dehydrogenase.