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PubMed1987

Production of Microbial Biomass Protein from Potato Processing Wastes by Cephalosporium eichhorniae.

The use of Cephalosporium eichhorniae 152 (ATCC 38255) (reclassified as Acremonium alabamense; see Addendum in Proof), a thermophilic, acidophilic, amylolytic fungus, for the conversion of potato processing wastes into microbial protein for use as animal feed was studied. The fungus was not inhibited by alpha-solanine or beta-2-chaconine, antimicrobial compounds in potatoes, or by morpholine or cyclohexylamine (additives to steam used in the peeling process) at levels likely to be encountered in this substrate. Mixed effluent from holding tanks at a potato-processing plant contained about 10 bacteria per ml and inhibited fungal growth. The fungus grew well on fresh potato wastes containing up to 5% total carbohydrate and utilized both starch and protein at 45 degrees C and pH 3.75. On potato homogenate medium containing 2% carbohydrate (about 14% fresh potato) supplemented with monoammonium phosphate (0.506 g/liter) and ferric iron (0.1 g/liter), with pH control (at 3.75) and additional nitrogen supplied by the automatic addition of ammonium hydroxide, typical yields were 0.61 g (dry weight) of product and 0.3 g of crude protein per g of carbohydrate supplied. An aerobic, spore-forming bacterium, related to Bacillus brevis, commonly contaminated nonsterilized batch cultures but was destroyed by heating for 15 min at 100 degrees C.

Journal Article↗
PubMed1975

Rumen bypass and protection of proteins and amino acids.

Potent rumen microbial proteases and deaminases rapidly degrade protein and amino acids which are soluble in the rumen liquid phase. Because protein sources vary in their solubility, the degree of degradation in the rumen is variable. Methods of decreasing protein and amino acid degradation in the rumen include heat treatment, chemical treatment, encapsulation, use of amino acid analogs, selective manipulation of balances of rumen metabolic pathways, and esophageal groove closure. It is important that procedures do not interfere with ruminal metabolism or post-ruminal digestion. Bypassing the rumen changes sites in the digestive tract of nutrient digestion and absorption and provides a mechanism for supplementing outflow of nutrients from the rumen. A feasible approach to production of animal protein from ruminants would be utilization of nonprotein nitrogen for rumen protein production, maximization of rumen bypass of dietary protein, and supplementation with rumen nondegradable amino acids.

Amino Acids↗
PubMed1975

Nitrogen utilization within equine large intestine.

The distribution of nitrogen in ligated segments of the stomach and intestine of two groups of ponies has been examined at sacrifice 2, 4, 8, and 12 h following the final 12-h scheduled feeding of diets designed to provide either 1) ample protein, or 2) limited protein plus supplemental urea as the major nitrogen source. Concentrations and total quantities of total N, NH3, urea plus NH3, and alpha-amino N were determined, and protein N was calculated by difference. Liquid marker (PEG) distribution rate constants and N concentrations were used to calculate rates of entry and exit by digesta flow for the large intestinal compartments. These values, together with measured accumulations of each constituent, allowed assessment of transitory net appearance and net disappearance within each compartment due to processes other than flow along the tract. The data suggested cyclic fluctuations of microbial populations within the large intestine, particularly the dorsal and ventral colon. These segments also were implicated as major sites of microbial protein synthesis and degradation. the former process appeared more evident in animals consuming the urea-supplemented diet.

Amino Acids↗
PubMed2006

Yeasts in high Arctic glaciers: the discovery of a new habitat for eukaryotic microorganisms.

Recently a new habitat for microbial life has been discovered at the base of polythermal glaciers. In ice from these subglacial environments so far only non-photosynthetic bacterial communities were discovered, but no eukaryotic microorganisms. We found high numbers of yeast cells, amounting to a maximum of 4,000 CFU ml(-1) of melt ice, in four different high Arctic glaciers. Twenty-two distinct species were isolated, including two new yeast species. Basidiomycetes predominated, among which Cryptococcus liquefaciens was the dominant species (ca. 90% of total). Other frequently occurring species were Cryptococcus albidus, Cryptococcus magnus, Cryptococcus saitoi and Rhodotorula mucilaginosa. The dominant yeast species were psychrotolerant, halotolerant, freeze-thaw resistant, unable to form mycelium, relatively small-sized and able to utilize a wide range of carbon and nitrogen sources. This is the first report on the presence of yeast populations in subglacial ice.

Arctic Regions↗
PubMed1996

In vitro ruminal degradation and synthesis of protein on fractions extracted from alfalfa hay and silage.

Net release of degraded N as NH3 and total AA plus microbial protein synthesis, quantified from incorporation of 15NH3 into microbial protein, was used to estimate the rate and extent of in vitro degradation of protein fractions isolated from alfalfa hay and silage. Seven proteins (casein, alfalfa hay, alfalfa silage, extracts from alfalfa hay and silage, and residues from alfalfa hay and silage) were studied. Results from (NH4)2SO4 and SDS-PAGE fractionations suggested that soluble proteins in alfalfa hay and silage differed in susceptibility to proteolytic attack. Although the net release of NH3 plus total AA N from alfalfa silage and alfalfa silage extract was twofold greater than that from alfalfa hay and alfalfa hay extract, net microbial protein synthesis on alfalfa hay and alfalfa hay extract was 33 and 43% greater. Despite greater NPN content in alfalfa silage, protein degradation rate and estimated escape were similar for intact alfalfa hay (0.103/h and 43%) and silage (0.067/h and 43%). This result might be explained by the less efficient microbial utilization of silage NPN, greater protozoal numbers on hay, greater soluble true protein in hay, or differences in molecular mass and stability of soluble proteins in hay versus silage. Use of a two-compartment model, based on water-soluble and insoluble CP fractions assumed to pass with the liquid and solid phases, respectively, yielded RUP estimates for alfalfa hay and silage that were similar to NRC estimates.

Ammonia↗
PubMed2001

Porphyromonas endodontalis binds, reduces and grows on human hemoglobin.

Porphyromonas endodontalis is a black-pigmented, obligate anaerobic rod-shaped bacterium implicated as playing a major role in endodontic infections. We have previously shown that P. endodontalis requires the porphyrin nucleus, preferably supplied as hemoglobin, as a growth supplement. The bacteria also actively transport free iron, although this activity does not support growth in the absence of a porphyrin source. The purpose of this study was to further investigate the binding and subsequent utilization of human hemoglobin by P. endodontalis. P. endodontalis binds hemoglobin and reduces the Fe(III) porphyrin, resulting in a steady accumulation of ferrous hemoglobin. Reduction of methemoglobin was similar to the extracellular reduction of nitrobluetetrazolium in the presence of oxidizable substrate. Turbidimetric and viable cell determinations showed that P. endodontalis grew when supplied only hemoglobin. Therefore, we conclude that hemoglobin appears to serve as a sole carbon and nitrogen source, and that these bacteria reduce extracellular compounds at the expense of oxidized substrates.

Anaerobiosis↗
PubMed2005

Enhancing the growth of Vicia faba plants by microbial inoculation to improve their phytoremediation potential for oily desert areas.

Two experiments were conducted to investigate the effect of inoculating Vicia faba plants (broad beens) raised in clean and oily sand with nodule-forming rhizobia and plant-growth-promoting rhizobacteria (PGPR) on growth of these plants in sand and to test whether this can improve the phytoremediation potential of this crop for oily desert areas. It was found that crude oil in sand at concentrations < 1.0% (w/w) enhanced the plant heights, their fresh and dry weights, the total nodule weights per plant, and the nitrogen contents of shoots and fruits. Similar enhancing effects were recorded when roots of the young plants were inoculated with nodule bacteria alone, PGPR alone, or a mixture of one strain of nodule bacteria and one of the PGPR. Such plant growth effects were associated with a better phytoremediation potential of V. faba plants for oily sand. The total numbers of oil-utilizing bacteria increased in the rhizosphere and more hydrocarbons were eliminated in sand close to the roots. The nodule bacteria tested were two strains of Rhizobium leguminosarum and the PGPR were Pseudomonas aeruginosa and Serratia liquefaciens. The four strains were found to use crude oil, n-octadecane, and phenanthrene as sole sources of carbon and energy. It was concluded that coinoculation of V. faba plant roots in oily sand with nodule bacteria and PGPR enhances the phytoremediation potential of this plant for oily desert sand through improving plant growth and nitrogen fixation.

Biodegradation, Environmental↗
PubMed2000

Influence of Bos indicus crossbreeding and cattle age on apparent utilization of a high-grain diet.

Ten Bos indicus x MARC III (initial BW = 303 +/- 25 kg) and 10 MARC III (initial BW = 322 +/- 16 kg) steers were used in a 2 x 2 factorial design to determine whether cattle age or Bos indicus crossbreeding influence site of digestion of a high-grain diet. Initially, five Bos indicus x MARC III and five MARC III steers were fitted with duodenal cannulas and adapted to a 95% concentrate diet that was offered for ad libitum consumption for a 237-d feeding period (calves). During the feeding period, duodenal and fecal samples were collected during 4-d periods beginning on d 14, 67, 137, and 228. The remaining 10 steers were fed a forage-based diet for a targeted daily gain of .6 to .7 kg for 210 d (yearlings). Following this period, yearling steers were duodenally cannulated and adapted to the 95% concentrate diet. Yearling steers had ad libitum access to feed for 165 d, and samples were collected during 4-d periods beginning on d 13, 42, 102, and 159. Dry matter intake was 9.8 and 7.6 kg/d and daily gain was 1.35 and 1.16 kg in yearlings and calves, respectively. Apparent OM digestion in the stomach was greater (P < .01) in yearlings than in calves. In contrast, postruminal disappearance as a percentage of OM intake was greater (P = .05) in calves than in yearlings. Duodenal flows of total N, microbial N, nonmicrobial N, and total amino acids and total tract N digestibility were not affected (P > .05) by age or Bos indicus crossbreeding. Fecal N excretion was greater (P < .01) in yearlings than in calves. Results of this experiment suggest little effect of Bos indicus influence on utilization of a high-grain diet. However, more feed is digested in the rumen of yearlings than of calves consuming a high-grain diet.

Aging↗
PubMed1998

Effect of the synchronization of the degradation of dietary crude protein and organic matter and feeding frequency on ruminal fermentation and flow of digesta in the abomasum of dairy cows.

Four Holstein cows in midlactation were equipped with ruminal and abomasal cannulas and used to study the effect of synchronized degradation of crude protein (CP) and organic matter (OM) and feeding frequency on digestion and outflow of nutrients. A 4 x 4 Latin square design was used. Diets were arranged in a 2 x 2 factorial design; the four diets contained high ruminally degradable OM and high ruminally degradable CP, high ruminally degradable OM and low ruminally degradable CP, low ruminally degradable OM and high ruminally degradable CP, and low ruminally degradable OM and low ruminally degradable CP. In each period, cows were fed four times daily from d 1 to 14 and two times daily from d 15 to 28. Mean daily ruminal ammonia N concentration was reduced by high ruminally degradable OM, low ruminally degradable CP, and twice daily feeding. Fluctuation in ruminal ammonia N was lower when cows were fed four times daily than when cows were fed twice daily. Plasma urea N concentrations were lower for cows fed diets that were high in ruminally degradable CP. Higher CP flow in the abomasum was found for cows fed the diet containing high ruminally degradable OM and low ruminally degradable CP. Microbial dry matter and CP flow to the abomasum were higher for cows fed twice daily than for cows fed four times daily. Flow of OM in the abomasum was not altered by concentrations of ruminally degradable OM or CP. These results suggest that the available energy in the rumen (ruminally degradable OM) is the most limiting factor for ruminal N utilization under our experimental conditions. Use of these data may improve the prediction of plasma urea N.

Abomasum↗
PubMed2006

Escherichia coli O157:H7 survival and growth on lettuce is altered by the presence of epiphytic bacteria.

Escherichia coli O157:H7 can survive in low numbers in soil and on plants. Occasionally, conditions may occur in the field that lead to contamination of produce. Survival of enteric pathogens in the field is controlled to a certain extent by complex interactions with indigenous soilborne and seedborne epiphytes. Identifying these interactions may assist in developing strategies to improve produce safety. Two epiphytes were isolated from pathogen-contaminated plants that interact differently with E. coli O157:H7. Wausteria paucula enhanced the survival of E. coli O157:H7 six-fold on lettuce foliage grown from coinoculated lettuce seed. In contrast, Enterobacter asburiae decreased E. coli O157:H7 survival 20- to 30-fold on foliage. Competition also occurred in the rhizosphere and in plant exudate. This competition may be the result of E. asburiae utilization of several of the carbon and nitrogen substrates typically present in exudate and also used by E. coli O157:H7. Hence, competition observed on the plant may involve one or more nutrients provided by the plant. In contrast, a different mechanism may exist between E. coli O157:H7 and W. paucula since commensalism was only observed on foliage, not in the rhizosphere or plant exudate. Good agricultural practices that encourage the growth of competing bacteria, like E. asburiae, may reduce the incidence of produce contamination.

Antibiosis↗
PubMed1978

Efficiency of use of nitrogen from dried microbial cells after a period of N deprivation in growing pigs.

1. Semi-synthetic diets, with dried microbial cells (Pruteen) as the nitrogen source, were used to measure N retention in 50 kg pigs which had been given only sufficient N (5.3 g/d) to maintain N equilibrium for the previous 12 d. Control pigs were given 33.2 gN/d. 2. Metabolic faecal N losses were 1.62 g/d (1.2 g/kg dry matter eaten) and endogenous urinary losses were 3.90 g/d. 3. Realimentation of N-deprived pigs was achieved with diets providing 20.0, 33.2 and 67.4 g N/d and daily rates for N retention were 11.2, 17.8 and 25.9 respectively; the corresponding value for control pigs was 15.0 g. 'Catch-up' protein growth was demonstrated in pigs given both 33.2 and 67.4 g N/d. In the former instance, this was associated with an increase in the efficiency of utilization of dietary N. 4. The biological value of the protein in Pruteen was 0.85, and it appeared that under conditions of increased demand for N the pig could utilize some of the nucleic acid-N fraction of this protein source.

Amino Acids↗
PubMed1989

[The effect of energy concentration and source on the use of feed protein and NPN in lambs. 3. Allantoin excretion and microbial protein synthesis].

In an N balance experiment with male crossbreeding lambs at an age of 3 ... 4 months four different rations were given differing in energy concentration (high greater than 700 EFU cattle/kg DM and low less than 650 EFU cattle/kg DM) and in the energy source (sugar, starch or crude fibre) with crude protein intake being almost equal. The rations contained 2% urea. Microbial protein synthesis in the rumen was assessed according to ROTH and KIRCHGESSNER (1978) (1), RYS et al. (1975) (2) and BICKEL-BAUMANN and LANDIS (1986) (3) on the basis of allantoin excretion in urine. The highest ruminal protein synthesis quotas were 868 ... 921 mg protein N per kg LW0.75 in (2). In (3) 723 ... 766 mg protein N/kg LW0.75 were synthesized. From the 15N labelling of the supplemented urea and the excreted allantoin it could be calculated that 26 ... 40% of the microbial protein resulted from the urea-N of the ration. Despite a high crude protein content of the ration of between 16 and 17% in the DM and a relation of NPN: pure protein of 0.95 the utilization of the NPN in the ration was relatively high but slightly lower than the utilization of pure protein. The variants with higher energy concentration showed as a tendency higher allantoin excretion in spite of slightly lower dry matter intake and a slightly higher NPN utilization than the variants with lower energy concentration.

Allantoin↗
PubMedDate not supplied

[Bacteria of the genus Burkholderia as a typical component of the microbial community of sphagnum peat bogs].

Bacteria of the genus Burkholderia are a typical component of the microbial complex of sphagnum peat bogs and constitute a substantial portion of the aerobic chemoorganotrophic isolates which are routinely obtained from these environments on acidic nutrient media. The ecophysiological characteristics of the 27 strains of such organisms, which were isolated from the peat of acidic sphagnum bogs of the boreal and tundra zones of Russia, Canada, and Estonia, were investigated in the present paper. The overwhelming majority of the Burkholderia strains isolated from these bogs were phylogenetically close to the species B. glathei, B. phenazinium, B. fungorum, and B. caryophylli, the typical inhabitants of soil and plant rhizosphere. The bog isolates utilized a broad range of substrates as carbon and energy sources, including organic acids, sugars, polyalcohols, and certain aromatic compounds. All the strains studied were capable of growth on nitrogen-free media. They developed in the pH ranges of 3.5 to 7.4 and from 3 to 37 degrees C, with the optima at pH 5-7 and 11-23 degrees C, respectively. They were therefore moderately acidophilic, psychroactive, dinitrogen-fixing microorganisms well adapted to the conditions of acidic northern sphagnum bogs.

Burkholderia↗
PubMed1987

Microbiological systems in organic synthesis: preparation of racemic prenalterol utilizing Cunninghamella echinulata.

The fungal microorganism Cunninghamella echinulata was utilized to para-hydroxylate the synthetic substrate (+/-)-1-isopropylamino-3-phenoxy-propan-2-ol (1). The resulting product, (+/-)-1-(4-hydroxyphenoxy)-3-isopropylamino-propan-2-ol, or (+/-)-prenalterol, (2) was formed in greater than 85% yield. Extracts from incubates were derivatized with trifluoroacetic anhydride and the concentrations of 1 and 2 were determined by GC on a fused silica methyl silicone capillary column with nitrogen-phosphorus detection. At substrate concentrations of 100 and 200 mg/L, the biotransformation proceeds with apparent first-order kinetics. With higher concentrations, the kinetics of prenalterol formation and substrate uptake appear to be nonlinear with a Km value of 427.8 micrograms/mL and a Vmax value of 232.3 micrograms/mL/d. This suggests that the biotransformation may proceed through a single-capacity limited pathway. The microbial product was isolated and identified as (+/-)-prenalterol by comparison (mp, IR, MS, 1H NMR) with an authentic specimen.

Biotransformation↗
PubMed2004

Potential of fermentation profiling via rapid measurement of amino acid metabolism by liquid chromatography-tandem mass spectrometry.

Monitoring amino acid metabolism during fermentation has significant potential from the standpoint of strain selection, optimizing growth and production in host strains, and profiling microbial metabolism and growth state. A method has been developed based on rapid quantification of underivatized amino acids using liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) to monitor the metabolism of 20 amino acids during microbial fermentation. The use of a teicoplanin-based chiral stationary phase coupled with electrospray tandem mass spectrometry allows complete amino acid analyses in less than 4 min. Quantification is accomplished using five isotopically labeled amino acids as internal standards. Because comprehensive chromatographic separation and derivatization are not required, analysis time is significantly less than traditional reversed- or normal-phase LC-based amino acid assays. Intra-sample precisions for amino acid measurements in fermentation supernatants using this method average 4.9% (R.S.D.). Inter-day (inter-fermentation) precisions for individual amino acid measurements range from 4.2 to 129% (R.S.D.). Calibration curves are linear over the range 0-300 microg/ml, and detection limits are estimated at 50-450 ng/ml. Data visualization techniques for constructing semi-quantitative fermentation profiles of nitrogen source utilization have also been developed and implemented, and demonstrate that amino acid profiles generally correlate with observed growth profiles. Further, cellular growth events, such as lag-time and cell lysis can be detected using this methodology. Correlation coefficients for the time profiles of each amino acid measured illustrate that while several amino acids are differentially metabolized in similar fermentations, a select group of amino acids display strong correlations in these samples, indicating a sub-population of analytes that may be most useful for fermentation profiling.

Amino Acids↗
PubMed1990

Inhibition of proteolysis in alfalfa silages using heat at harvest: effects on digestion in the rumen, voluntary intake and animal performance.

The effects of proteolysis on digestion and animal performance were studied using heat to inhibit proteolysis at ensiling. Alfalfa (Medicago sativa) was ensiled either after wilting for 24 h (control; C) or after heating (100 degrees C) in a crop dehydrator for 2 min (heated; H). In Exp. 1, eight wethers, cannulated in the rumen and duodenum, were given the silages to determine the effects of heat treatment of alfalfa on the digestion of silage. In Exp. 2, growing lambs had ad libitum access to the silages to determine the effects of heat treatment on intake, animal performance and body composition. Heat treatment inhibited protease activity; protein N accounted for 33.5 and 61.3% and ammonia N 15.5 and 5.1% of total N in C and H silages, respectively. Heat treatment reduced mean post-feeding ruminal ammonia N concentration (P less than .05), ruminal pH (P less than .05) and the acetate: propionate ratio (P less than .001) in ruminal fluid. Heat treatment increased duodenal flow of non-ammonia N (P less than .05) and amino acids (P less than .05), the amount of N absorbed (P less than .05) in the small plus large intestine and also increased the efficiency of microbial protein synthesis (P less than .05). In Exp. 2, although intake and gain were higher (P less than .001) for H-fed than for C-fed lambs, there were no differences (P greater than .05) in empty body composition. The results indicated that inhibition of proteolysis by heat treatment at ensiling can increase utilization of silage N within the rumen, increase voluntary intake and result in a higher rate of gain by lambs fed alfalfa silage.

Animal Feed↗
PubMed2001

Fundamental processes within natural and constructed wetland ecosystems: short-term versus long-term objectives.

Use of wetland ecosystems for water pollution control consists essentially of sustained induced disturbances as pollutants are loaded to complex biological communities. Objectives are to maximize pollutant loading, incorporation, and retention while maintaining highest levels of community metabolism and minimal alteration of community structure. Several basic processes are emphasized: (a) macrophyte productivity in relation to shoot:root ratios, and nutrient availability; (b) macrophyte life history strategies, succession, and biodiversity under constant pollutant stress; (c) importance of standing dead and particulate detritus; (d) functions and controlling mechanisms of heterotrophic and autotrophic periphyton in pollutant retention and recycling; (e) coupling of microbial metabolism to macrophyte retention of pollutants; (f) gaseous losses to the atmosphere; (g) losses of dissolved organic matter and its utilization; and (h) water losses by evapotranspiration and effects on wetland efficacy. Short-term wetland removal efficiencies are confounded by massive variations in retentive capacities diurnally, seasonally, and spatially, in exceeding physiological tolerance levels, and in species succession. Problems of channelization, altered microhydrology, and assimilation/retention are major in natural and non-engineered ecosystems. Wetlands are highly ephemeral and variable in their capabilities for sequestering and retention of nutrients and other pollutants.

Ecosystem↗
PubMed2001

The complete sequence of the 1,683-kb pSymB megaplasmid from the N2-fixing endosymbiont Sinorhizobium meliloti.

Analysis of the 1,683,333-nt sequence of the pSymB megaplasmid from the symbiotic N(2)-fixing bacterium Sinorhizobium meliloti revealed that the replicon has a high gene density with a total of 1,570 protein-coding regions, with few insertion elements and regions duplicated elsewhere in the genome. The only copies of an essential arg-tRNA gene and the minCDE genes are located on pSymB. Almost 20% of the pSymB sequence carries genes encoding solute uptake systems, most of which were of the ATP-binding cassette family. Many previously unsuspected genes involved in polysaccharide biosynthesis were identified and these, together with the two known distinct exopolysaccharide synthesis gene clusters, show that 14% of the pSymB sequence is dedicated to polysaccharide synthesis. Other recognizable gene clusters include many involved in catabolic activities such as protocatechuate utilization and phosphonate degradation. The functions of these genes are consistent with the notion that pSymB plays a major role in the saprophytic competence of the bacteria in the soil environment.

Bacterial Proteins↗