Metabolites ofStreptomyces noursei

Branched chain amino acids are degraded byStreptomyces noursei to the corresponding amides: valine being the precursor of isobutyramide, leucine of isovaleramide and isoleucine of anteisovaleramide. The formation of amides is pyridoxalphosphate dependent and is catalyzed by peroxidase. Furthermore it was found that branched chain amino acids were also degraded via the corresponding 2-oxoacids into acylCoA which can be dehydrogenated to unsaturated acylCoA or hydrolyzed to acids and CoASH.     

Regulation of biosynthesis of secondary metabolites

The quantity of the synthetized and degraded fatty acids during the production phase ofStreptomyces aureofaciens was in vestigated. Of the acids present in the mycelium in the 24th hour, 39% had been degraded between the 24th and 48th hour of growth and 61% between the 24th and 72nd hour of growth. Of the fatty acids synthetized after the 24th hour, 20.7% were degrated towards the 48th hour and 36.3% towards the 72nd hour. The total quantity of fatty acids synthetized during 96 hours of fermentation was calculated on models. From this amount 40% only would remain in the 96th hour mycelium; the remainder would be degraded during fermentation.     

Formalized analysis of associativity of morphogenetic types and humus condition of ground litter in marsh birch forests

There are six morphogenetic types of forest ground litter in the gradient of big grass-sphagnous-dead litter marsh birch forest: deeply degraded litter, half degraded litter, rhizomatous litter (coarsely degraded), peaty litter, turfy-formed litter, and turfy litter. The specificity of their biochemical transformations is caused by the accumulation of humic acids (HA), especially of the first fraction (HA-1), alongside the relatively steady background formation of fulvic acids. The C/N value suggests that the intensity of HA-1 formation is closely associated with the biological activity of the substrate. However, the indistinct difference of these parameters in the forestry-morphological types of litters limits their diagnostic reliability. Grouped biochemical types of litters, such as “soft” (half- and deeply degraded), “intermediate” (rhizomatous, peaty and turfy-formed), and “coarse” (mossy), are considerably discriminated by both the C/N ratio (20, 30, 40) and the level of HA-1 (14, 10, and 6%) respectively.     

The constituent cutin acids of cranbury cuticle

Purified cutin from cranberry (Vaccinium macrocarpon, var. Howes) skin was selectively degraded, and the cutin acids, as methyl esters, separated by TLC into seven classes including monobasic acids, dibasic acids, monohydroxy monobasic acids, monohydroxy epoxymonobasic acids, vic-dihydroxy dibasic acids, dihydroxy monobasic acids and trihydroxy monobasic acids. Of the 41 components identified in cranberry cutin by GLC and MS analysis, 18-hydroxyoctadec-cis-9-enoic acid (9·4%), 18-hydroxy-cis-9,10-epoxyoctadecanoic acid (7·5%), 10,16-dihydroxyhexadecanoic acid (16·7%) and threo-9,10,18-trihydroxyoctadecanoic acid (43·7%) were shown to be the major constituents.     

Cooperation between Lactococcus lactis and Nonstarter Lactobacilli in the Formation of Cheese Aroma from Amino Acids

In Gouda and Cheddar type cheeses the amino acid conversion to aroma compounds, which is a major process for aroma formation, is essentially due to lactic acid bacteria (LAB). In order to evaluate the respective role of starter and nonstarter LAB and their interactions in cheese flavor formation, we compared the catabolism of phenylalanine, leucine, and methionine by single strains and strain mixtures of Lactococcus lactis subsp. cremoris NCDO763 and three mesophilic lactobacilli. Amino acid catabolism was studied in vitro at pH 5.5, by using radiolabeled amino acids as tracers. In the presence of α-ketoglutarate, which is essential for amino acid transamination, the lactobacillus strains degraded less amino acids than L. lactis subsp. cremoris NCDO763, and produced mainly nonaromatic metabolites. L. lactis subsp. cremoris NCDO763 produced mainly the carboxylic acids, which are important compounds for cheese aroma. However, in the reaction mixture containing glutamate, only two lactobacillus strains degraded amino acids significantly. This was due to their glutamate dehydrogenase (GDH) activity, which produced α-ketoglutarate from glutamate. The combination of each of the GDH-positive lactobacilli with L. lactis subsp. cremoris NCDO763 had a beneficial effect on the aroma formation. Lactobacilli initiated the conversion of amino acids by transforming them mainly to keto and hydroxy acids, which subsequently were converted to carboxylic acids by the Lactococcus strain. Therefore, we think that such cooperation between starter L. lactis and GDH-positive lactobacilli can stimulate flavor development in cheese.     

Effect of different supplements on bioprocessing of wheat straw by Phlebia brevispora: changes in its chemical composition, in vitro digestibility and nutritional properties

Bioprocessing of wheat straw was carried out by Phlebia brevispora under solid state conditions. Effect of different supplements on lignocellulolytic enzymes production, degradation of straw cell wall fibers and its resultant effect on nutritional quality of wheat straw were studied. Ammonium chloride and malt extract were more effective in terms of ligninolysis and enhanced in vitro digestibility. The concentration of the selected supplements and the moisture content was worked out using response surface methodology in order to minimize the loss in total organic matter so as to selectively degrade lignin. The experiment was scaled up to batches of 200 g under optimized conditions and the degraded substrate was analyzed for its biochemical properties. P. brevispora degraded 290 g/kg of lignin and enhanced the in vitro digestibility from 150 to 268 g/kg (78%). Crude protein, amino acids, total phenolic contents and antioxidant properties were significantly higher in degraded straw.     

The oxidation of aldoses and aldonic acids with pentavalent vanadium in m sulphuric acid

Aldoses are degraded by vanadium pentaoxide in m sulphuric acid into formic acid and the next lower aldose, and aldonic acids are degraded into carbon dioxide and the next lower aldose. Each reaction consumes two equivalents of oxidant. Glycoaldehyde is oxidized to formic acid via glyoxal, and glycolic acid is oxidized to carbon dioxide and formic acid via glyoxylic acid.     

Microbial Degradation of a Macrotetrolide Miticide in Soil

Macrotetrolide, a miticide consisting of tetranactin, trinactin, and dinactin, was readily biodegradable and hence did not accumulate in soil. [U-¹⁴C]macrotetrolide was rapidly degraded via its constituent hydroxycarboxylic acids to carbon dioxide and water. In culture media, however, the mixture was hydrolyzed to homononactic and nonactic acids by three strains of Bacillus sp. and two of Micrococcus sp. The latter strains were able to hydrolyze 500 μg of the antibiotic per ml within a few days and to grow in the presence of 4,000 μg of the antibiotic per ml. However, they were unable to assimilate the constituent acids which accumulated in the culture medium.     

Structural proteins of Amsacta moorei,Euxoa auxiliaris, and Melanoplus sanguinipes entomopoxviruses

The structural proteins of Amsacta moorei, Euxoa auxiliaris, and Melanoplus sanguinipes entomopoxviruses (EPVs) were separated by electrophoresis on sodium dodecyl sulfate (SDS)-polyacrylamide gels. More than 35 structural proteins were detected in each virus. Based on the distribution and the variation in the molecular weights of the virus structural proteins little homology was detected between the EPVs and vaccinia virus. The molecular weight of Amsacta EPV occlusion body matrix protein (110,000) was determined by SDS-acrylamide gel electrophoresis. The occlusion body matrix protein of Amsacta EPV occluded virus isolated from infected E. acrea larvae was rapidly degraded at pH 10.6 to peptides of approximately 94,000 and 60,000 daltons. After 2 hr incubation at alkaline pH, Amsacta EPV occlusion body protein was degraded to approximately 56,000 daltons. Proteolysis of occlusion body protein was inhibited by SDS. No proteolytic degradation was detected in occlusion body matrix protein isolated from Amsacta EPV infected BTI-EAA cells. Amino acid analysis indicates that entomopoxvirus occlusion body matrix protein consists of approximately 20% acidic amino acids and 9% of the sulfur-containing amino acids cysteine and methionine.     

Degradation of paper mill water components in laboratory tests with pure cultures of bacteria

The degradation of dissolved and colloidal substances from thermomechanical pulp (TMP) by bacteria isolated from a paper mill was studied in a laboratory slide culture system.Burkholderia cepacia strains hydrolysed triglycerides to free fatty acids, and the liberated unsaturated fatty acids were then degraded to some extent. Saturated fatty acids were not notably degraded. However, the branched anteiso-heptadecanoic fatty acid was degraded almost like the unsaturated fatty acids. About 30% of the steryl esters were degraded during 11 days, increasing the concentrations of free sterols. Approximately 25% of the dehydroabietic, and 45% of the abietic and isopimaric resin acids were degraded during 11 days. The degree of unsaturation seemed to be of greater importance for the degradation of fatty acids than the molar mass. No degradation of dissolved hemicelluloses could be observed with any of the nine bacterial strains studied. Burkholderia cepacia strains and one Bacillus coagulans strain degraded monomeric fructose and glucose in winter TMP water, but in summer TMP water, with much lower sugar concentrations, also otherBacillus strains degraded monomeric sugars.     

Isolation of Acinetobacter calcoaceticus strains degrading the volatile fatty acids of swine wastes

Two Acinetobacter calcoaceticus strains were isolated from swine slurry which degraded the volatile fatty acids (VFA) contained in a mineral medium and in sterilized and non-sterilized swine slurry within 21 days at 22°C. Acetic acid was the predominant VFA in the swine wastes. Due to the strict aerobic metabolism of A. calcoaceticus, it is suggested that this organism causes variations in the volatile fatty acids concentration according to the depth of storage of the wastes. Some variations of the VFA concentrations not due to microbial activity were observed.     

Stable-Isotope-Based Labeling of Styrene-Degrading Microorganisms in Biofilters

Deuterated styrene ([²H₈]styrene) was used as a tracer in combination with phospholipid fatty acid (PLFA) analysis for characterization of styrene-degrading microbial populations of biofilters used for treatment of waste gases. Deuterated fatty acids were detected and quantified by gas chromatography-mass spectrometry. The method was evaluated with pure cultures of styrene-degrading bacteria and defined mixed cultures of styrene degraders and non-styrene-degrading organisms. Incubation of styrene degraders for 3 days with [²H₈]styrene led to fatty acids consisting of up to 90% deuterated molecules. Mixed-culture experiments showed that specific labeling of styrene-degrading strains and only weak labeling of fatty acids of non-styrene-degrading organisms occurred after incubation with [²H₈]styrene for up to 7 days. Analysis of actively degrading filter material from an experimental biofilter and a full-scale biofilter by this method showed that there were differences in the patterns of labeled fatty acids. For the experimental biofilter the fatty acids with largest amounts of labeled molecules were palmitic acid (16:0), 9,10-methylenehexadecanoic acid (17:0 cyclo9-10), and vaccenic acid (18:1 cis11). These lipid markers indicated that styrene was degraded by organisms with a Pseudomonas-like fatty acid profile. In contrast, the most intensively labeled fatty acids of the full-scale biofilter sample were palmitic acid and cis-11-hexadecenoic acid (16:1 cis11), indicating that an unknown styrene-degrading taxon was present. Iso-, anteiso-, and 10-methyl-branched fatty acids showed no or weak labeling. Therefore, we found no indication that styrene was degraded by organisms with methyl-branched fatty fatty acids, such as Xanthomonas, Bacillus, Streptomyces, or Gordonia spp.     

Anaerobic Degradation of Normal- and Branched-Chain Fatty Acids with Four or More Carbons to Methane by a Syntrophic Methanogenic Triculture

Syntrophic degradation of normal- and branched-chain fatty acids with 4 to 9 carbons was investigated with a mesophilic syntrophic isobutyrate-butyrate-degrading triculture consisting of the non-spore-forming, syntrophic, fatty acid-degrading, gram-positive rod-shaped strain IB, Methanobacterium formicicum T1N, and Methanosarcina mazei T18. This triculture converted butyrate and isobutyrate to methane and converted valerate and 2-methylbutyrate to propionate and methane. This triculture also degraded caproate, 4-methylvalerate, heptanoate, 2-methylhexanoate, caprylate, and pelargoate. During the syntrophic conversion of isobutyrate and butyrate, a reversible isomerization between butyrate and isobutyrate occurred; isobutyrate and butyrate were isomerized to the other isomeric form to reach nearly equal concentrations and then their concentrations decreased at the same rates. Butyrate was an intermediate of syntrophic isobutyrate degradation. When butyrate was degraded in the presence of propionate, 2-methylbutyrate was synthesized from propionate and isobutyrate formed from butyrate. During the syntrophic degradation of valerate, isobutyrate, butyrate, and 2-methylbutyrate were formed and then degraded. During syntrophic degradation of 2-methylbutyrate, isobutyrate and butyrate were formed and then degraded.     

Changes in fatty acid composition of <Emphasis Type="Italic">Stenotrophomonas maltophilia</Emphasis> KB2 during co-metabolic degradation of monochlorophenols

The changes in the cellular fatty acid composition of Stenotrophomonas maltophilia KB2 during co-metabolic degradation of monochlorophenols in the presence of phenol as well as its adaptive mechanisms to these compounds were studied. It was found that bacteria were capable of degrading 4-chlorophenol (4-CP) completely in the presence of phenol, while 2-chlorophenol (2-CP) and 3-chlorophenol (3-CP) they degraded partially. The analysis of the fatty acid profiles indicated that adaptive mechanisms of bacteria depended on earlier exposure to phenol, which isomer they degraded, and on incubation time. In bacteria unexposed to phenol the permeability and structure of their membranes could be modified through the increase of hydroxylated and cyclopropane fatty acids, and straight-chain and hydroxylated fatty acids under 2-CP, 3-CP and 4-CP exposure, respectively. In the exposed cells, regardless of the isomer they degraded, the most important changes were connected with the increase of the contribution of branched fatty acid on day 4 and the content of hydroxylated fatty acids on day 7. The changes, particularly in the proportion of branched fatty acids, could be a good indicator for assessing the progress of the degradation of monochlorophenols by S. maltophilia KB2. In comparison, in phenol-degrading cells the increase of cyclopropane and straight-chain fatty acid content was established. These findings indicated the degradative potential of the tested strain towards the co-metabolic degradation of persistent chlorophenols, and extended the current knowledge about the adaptive mechanisms of these bacteria to such chemicals.     

Catabolism of Amino Acids by Megasphaera elsdenii LC1

The amino acids in an acid hydrolysate of casein were catabolized more extensively by Megasphaera elsdenii than those in an enzymic hydrolysate. Threonine and serine were most actively degraded, but no resultant increase in growth yield occurred. Branched-chain volatile fatty acid production, which increased as the dilution rate of a glucose-limited chemostat decreased, seemed to be associated with maintenance rather than with growth.     

Abbau chlorierter Benzole,Phenole und Cyclohexan-Derivate durch Benzol und Phenol verwertende Bodenbakterien unter aeroben Bedingungen

From soil samples of different origin (field, grassland and forest soils) small numbers ofNocardin andPseudomonas spec., able to utilize benzene and phenol could be isolated. Organisms which could only utilize phenol and phenolcarboxylic acids were more numerous and consisted mainly ofArthrobacter spec. It was tested to what extent these organisms could also utilize chlorinated aromatic and cyclohexane derivatives. For the degradation studies the bacteria were precultivated on benzene or p-hydroxybenzoic acid and then the compounds used were added. These compounds were labeled by¹⁴C and their degradation rates determined by measuring the¹⁴CO₂ release.Pseudomonas andNocardia spec. precultivated on benzene could also degrade the chlorinated derivatives of benzene and phenol. The monochlorinated derivates were degraded more easily than the di- and trichlorinated derivates. The chlorinated benzenes, especially in higher concentrations, were less degraded than the chlorinated phenols, but with lower concentrations their degradation rates were about similar. This was due to a higher toxicity of the benzenes. The phenol utilizingArthrobacter spec. were only able to degrade phenol and the chlorinated phenols. Benzoic and m-chlorobenzoic acid were degraded to CO₂ by thePseudomonas andNocardia spec. only. The benzene utilizing pseudomonads released more CO₂ from γ-pentachlorocyclohexane than from γ-hexachlorocyclohexane, but none from cyclehexane. Upon precultivation of benzene utilizing pseudomonads in glucose, the aromatic compounds were also degraded, but especially the chlorinated derivatives to a lower extent. In comparison with these soil organisms in pure culture, experiments with soil samples showed a degradation of all compounds which were used by the isolated organisms after variable induction periods. Cyclohexane was degraded slowly to CO₂ by the mixed soil flora in contrast to the benzene or phenol utilizing pure cultures.     

Ueber den abbau von polyphenolen durch pilze der gattung Fusarium

The ability of 16 Fusarium species to degrade polyphenols was investigated. Phenols, benzoic acids, cinnamic acids, flavonoids and isoflavones are efficiently catabolized by all strains investigated. o-coumaric acid is transformed into 4-hydroxycoumarin by 7 species. A pronounced capability for methyl ether cleavage is demonstrated by stepwise o-demethylation of veratric acid and 5,7,4′-trimethoxyisoflavone. The latter compound is degraded via the sequence: 5,7,4′-trimethoxyisoflavone → 5,4′-dimethoxy-7-hydroxyisoflavone → biochanin A → genistein → orobol → ring fission products.     

Degradation of Glucose by Proliferating Cells of Desulfotomaculum nigrificans

Desulfotomaculum nigrificans degraded glucose to acetate, ethyl alcohol, and carbon dioxide. By use of ¹⁴C-glucose labeled at different carbon atoms, two pathways of glucose metabolism were detected. They were the Embden-Meyerhof and the Entner-Doudoroff schemes. Because the observed quantities of acetate and carbon dioxide, arising from glucose, were greater than the expected theoretical values, individual fermentations were conducted with 15 uniformly labeled ¹⁴C-amino acids. The results indicated that amino acids, supplied by the yeast extract or peptone in the fermentation medium, also contributed to the formation of acetate and carbon dioxide.     

Fasciola hepatica: Energy sources and metabolism

Gas chromatographic determination of biliary glucose in the rat showed only low levels were present. Although flukes took up glucose from the bile in vivo, biliary glucose could not be a major energy source as occurs in Hédon Fleig solution in vitro. Alanine, arginine, glutamate, histidine, phenylalanine, and serine were not metabolised in vitro to volatile fatty acids, and mixtures of peptides or amino acids failed to spare glycogen breakdown in the absence of glucose. Although glycerol was metabolised in vitro, the main energy source of the fluke in vivo has not been identified. Labelling studies confirmed that glucose taken up in vitro is degraded via glycolysis rather than the pentose phosphate pathway.     

Industrial biotransformations for the production of d-amino acids

Optically pure d-amino acids are industrially manufactured by biotransformations of cheap starting materials produced by chemical synthesis or fermentation in combination with the development of enzyme catalysts suitable for the starting materials. dl-Alaninamide, an intermediate of the chemical synthesis of dl-alanine, was efficiently converted to d-alanine by stereoselective hydrolysis with a d-isomer specific amidohydrolase produced by Arthrobacter sp. NJ-26. The total utilization system of dl-alaninamide for the production of optically pure d- and l-alanine was constructed by stereospecific amidohydrolases. On the other hand, d-amino acids were also produced from corresponding l-isomers, which are efficiently manufactured by fermentation. d-Glutamic acid was produced from l-glutamic acid. l-Glutamate was converted to the dl-form by the recombinant glutamate racemase of Lactobacillus brevis ATCC8287. Then l-glutamate in a racemic mixture was selectively decarboxylated to γ-aminobutyrate by the l-glutamate decarboxylase of E. coli ATCC11246. As a result of successive enzymatic reactions, d-glutamate was efficiently produced from l-glutamate by a one-pot reaction. d-Proline was produced by the same strategy from l-proline using the recombinant proline racemase of Clostridium sticklandii ATCC12262. In this case, l-proline was degraded by Candida sp. PRD-234. The strategy from l-amino acids to d-amino acids could be applicable to the manufacture of many d-amino acids.