Identification and methionine analog tolerance of environmental bacterial isolates selected on methionine analog containing medium

Methionine is the first limiting amino acid in poultry feed. Currently, methionine supplement is synthesized from an expensive chemical process requiring hazardous chemicals. Therefore, the objectives of this study were isolation of methionine producing bacteria from environmental samples and quantification of methionine production in these isolated bacteria. MCGC medium was selected as the isolation medium for methionine-producing bacteria by using Corynebacterium glutamicum ATCC13032 and Escherichia coli ATCC23798 as the positive and negative controls, respectively. Thirty-nine bacterial strains were obtained from environmental samples. Only strains A121, A122, A151 and A181 were able to tolerate up to 0.1% (w/v) of ethionine or norleucine. These isolated strains were identified by sequencing small subunit rRNA genes. The results revealed that bacterial strains A121, A122, A151and A181 were Klebsiella species, Acinetobacter baumannii, A. baumannii and Pseudomonas aeruginosa, respectively. When methionine production in strains A121 and A181 was quantitated, strains A121 and A181 generated methionine up to 31.1 and 124.6 μg/ml, respectively.     

Effect of Fractionation and Pyrolysis on Fuel Properties of Poultry Litter

Abstract

Raw poultry litter has certain drawbacks for energy production such as high ash and moisture content, a corrosive nature, and low heating values. A combined solution to utilization of raw poultry litter may involve fractionation and pyrolysis. Fractionation divides poultry litter into a fine, nutrient-rich fraction and a coarse, carbon-dense fraction. Pyrolysis of the coarse fraction would remove the corrosive volatiles as bio-oil, leaving clean char. This paper presents the effect of fractionation and pyrolysis process parameters on the calorific value of char and on the characterization of bio-oil. Poultry litter samples collected from three commercial poultry farms were divided into 10 treatments that included 2 controls (raw poultry litter and its coarse fraction having particle size greater than 0.85 mm) and 8 other treatments that were combinations of three factors: type (raw poultry litter or its coarse fraction), heating rate (30 or 10 °C/min), and pyrolysis temperature (300 or 500 °C). After the screening process, the poultry litter samples were dried and pyrolyzed in a batch reactor under nitrogen atmosphere and char and condensate yields were recorded. The condensate was separated into three fractions on the basis of their density: heavy, medium, and light phase. Calorific value and proximate and nutrient analysis were performed for char, condensate, and feedstock. Results show that the char with the highest calorific value (17.39 ± 1.37 MJ/kg) was made from the coarse fraction at 300 °C, which captured 68.71 ± 9.37% of the feedstock energy. The char produced at 300 °C had 42 ± 11 mg/kg arsenic content but no mercury. Almost all of the Al, Ca, Fe, K, Mg, Na, and P remained in the char. The pyrolysis process reduced ammoniacal-nitrogen (NH₄-N) in char by 99.14 ± 0.47% and nitrate-nitrogen (NO₃-N) by 95.79 ± 5.45% at 500 °C.     

Presence of bacteriophages in animal feed as indicators of fecal contamination

The objectives of this study were to determine if indigenous male specific and somatic bacteriophages could be detected in animal feeds and if isolated phages contained RNA or DNA. Seven fresh feeds, 2 fresh feed ingredients, 7 stored feeds, 2 stored feed ingredients, and 8 samples of poultry diets suspected to contain Salmonella spp. were enriched and spot plated for indigenous phages using Escherichia coli Famp and CN-13 as hosts. Bacteriophage numbers were below detection without enrichment, but both male specific and somatic coliphages were detected in all animal feeds, feed ingredients, and poultry diets after 16 h of enrichment, even after the samples had been stored for 14 months of storage at -20 C. Five out of 9 fresh feeds and 7 out of 8 stored feeds contained RNA somatic phages.     

Quantification of ionophores in aged poultry litter using liquid chromatography tandem mass spectrometry

Veterinary anticoccidials, biochemically known as ionophores, are widely used in poultry feed at therapeutic levels to treat Coccidiosis and at sub-therapeutic levels for growth- promotion. Commonly used ionophores in the US poultry industry are monensin, salinomycin, lasalocid and narasin. There is an increasing concern regarding the persistence of these anticoccidials in the environment. However, little attention has been directed to methods development for quantitatively measuring ionophores in complex environmental matrices such as poultry litters that are land applied. Here, we describe a rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS)-based method developed for simultaneous quantification of monensin, lasalocid, salinomycin, and narasin in aged poultry litter samples. Results show significant level of monensin (97.8 ± 3.2 μg kg^?1), lasalocid (19.2 ± 6.6 μg kg^?1), salinomycin (70 ± 2.7 μg kg^?1) and narasin (57.3 ± 2.6 μg kg^?1) in poultry litter stored for over three years at < 5°C. Our findings indicate that even after several years of unmanaged storage of poultry litter, ionophores may continue to persist in this matrix, raising the possibility of prolonged release into the environment.     

The Combination of Zinc Compounds and Acidic pH Limits Aerobic Growth of a Salmonella typhimurium Poultry Marker Strain in Rich and Minimal Media

Abstract

The objective of the present study was to examine the combined effects of zinc compounds with different acidic pH levels on the aerobic growth of a S. typhimurium poultry isolate in either rich or minimal media. When overall main effects of pH levels of medium or concentrations of Zn compounds were compared, growth rates of the S. typhimurium poultry isolate were significantly ( p < 0.05) decreased by stepwise increase of pH levels of medium (pH 4, 5, 6, and 7) or concentrations (0.67, 3.35, and 6.03%) of Zn compounds (Zn acetate and Zn sulfate). In general growth rates of S. typhimurium poultry isolate appeared to be more reduced by Zn acetate than by Zn sulfate and more reduced in minimal media compared to rich media.     

Reduction of nitrogen excretion and emission in poultry: A review for organic poultry

Organic poultry is an alternative to conventional poultry which is rapidly developing as a response to customers' demand for better food and a cleaner environment. Although organic poultry manure can partially be utilized by organic horticultural producers, litter accumulation as well as excessive nitrogen still remains a challenge to maintain environment pureness, animal, and human health. Compared to conventional poultry, diet formulation without nitrogen overloading in organic poultry is even more complicated due to specific standards and regulations which limit the application of some supplements and imposes specific criteria to the ingredients in use. This is especially valid for methionine provision which supplementation as a crystalline form is only temporarily allowed. This review is focused on the utilization of various protein sources in the preparation of a diet composed of 100% organic ingredients which meet the avian physiology need for methionine, while avoiding protein overload. The potential to use unconventional protein sources such as invertebrates and microbial proteins to achieve optimal amino acid provision is also discussed.     

Alternative low-cost process for large-scale production of Bacillus thuringiensis in a simple and novel culture system

Abstract

An industrial-scale, profitable method for production of the most widely used bioinsecticide, Bacillus thuringiensis (Bt), is challenging because of its widespread application. The aim of this study is to present a strategy to develop a low-cost, large-scale bioprocess to produce Bt H14.

This study was first focused on the design of a culture medium composed of economical and available components, such as glycerol and lysed Saccharomyces cerevisiae. The production goal of 1200 ITU was achieved using a medium composed of 20:20 g L^?1of glycerol:lysed yeast in batch cultures. Efforts were subsequently focused on the design of an appropriate culture system, and an original two-stage culture system was proposed. First, yeast (the primary component of the culture medium) are cultivated using a minimal mineral medium and lysed, and in the second stage, Bt is cultivated in the same bioreactor using the lysed yeasts as culture medium (supplemented with a feeding pulse of 10 g L^?1 glycerol). This system was called fed batch one pot (FOP). A new inoculation strategy is also presented in this study, since these Bt cultures were inoculated directly with heat pre-treated spores instead of vegetative bacteria to facilitate the bioprocess. This study was developed from the laboratory to production-scale bioreactors (measuring from 500 mL to 2500 L), and the efficiency of the proposed strategy was evident in LD₅₀ tests results, achieving 1796 ITU in large-scale processes. Both the use of non-conventional sources and the process development for biomass production are important for cost-effective production of Bt-based insecticides in mosquito control projects.     

Degradation of chlorpyrifos by an endophytic bacterium of the Sphingomonas genus (strain HJY) isolated from Chinese chives (Allium tuberosum)

The degradation of chlorpyrifos (CP) by an endophytic bacterial strain (HJY) isolated from Chinese chives (Allium tuberosum Rottl. ex Spreng) was investigated. Strain HJY was identified as Sphingomonas sp. based on morphological, physiological, and biochemical tests and a 16S rDNA sequence analysis. Approximately 96% of 20 mg L^?1 CP was degraded by strain HJY over 15 days in liquid minimal salts medium (MSM). The CP degradation rate could also be increased by glucose supplementation. The optimal conditions for the removal of 20 mg L^?1 CP by strain HJY in MSM were 2% inoculum density, pH 6.0, and 30–35°C. The CP degradation rate constant and half-life were 0.2136 ± 0.0063 d^?1 and 3.2451 ± 0.0975 d, respectively, under these conditions, but were raised to 0.7961 ± 0.1925 d^?1 and 0.8707 ± 0.3079 d with 1% glucose supplementation. The detection of metabolic products and screening for degrading genes indicated that O,O-diethyl O-3,5,6-trichloropyridinol was the major degradation product from CP, while it was likely that some functional genes were undetected and the mechanism responsible for CP degradation by strain HJY remained unknown. Strain HJY is potentially useful for the reduction of CP residues in Chinese chives and may be used for the in situ phytoremediation of CP.     

Biodegradation of α and β Endosulfan in Soil as Influenced by Application of Different Organic Materials

Abstract

A laboratory pot experiment was conducted to study the effect of amending soil with four different sources of organic matter on the degradation rate of α and β endosulfan isomers. Poultry by-product meal, poultry manure, dairy manure, and municipal solid waste compost were cured, dried, ground (<1 mm) and thoroughly mixed with a calcareous soil at a rate of 2% and placed in plastic pots. Endosulfan was added at the rate of 20 mg kg^?1. The moisture level was kept near field capacity and the pots were kept at room temperature. Soil sub-samples, 100 g each, were collected from every pot at days 1, 8, 15, 22, 29, 43, and 57 for the measurement of endosulfan isomers. Endosulfan residues were extracted from the soil samples with acetone. The supernatant was filtered through anhydrous sodium sulphate, 5 mL aliquot was diluted to 25 mL with hexane, mixed well, and then two sub-samples from the filtrates were analyzed for α and β endosulfan isomers by gas chromatography. The results indicated that the half-life (T _½) of α-endosulfan in the poultry by-product meal treatment was 15 days compared to about 22 days in the other treatments. The T _½ of β-endosulfan was 22 days in the poultry by-product meal treatment and followed a bi-phasic pattern, 57 days in the municipal solid waste compost treatment and the extrapolated T _½ was about 115 days for the other three treatments.     

Isolation and characterization of biarylic structure-degrading yeasts: hydroxylation potential of dibenzofuran

Yeast communities from heavily polluted sediments that received the discharge from oil refineries and other industries were studied. Yeast species were isolated from these sediments and their ability to degrade dibenzofuran were determined. Twenty-four different yeast strains were isolated and cultured on aromatic medium; two Candida krusei strains. Candida tenuis, Candida tropicalis, two Pichia anomala strains, Pichia haplophila, two Rhodotorula glutinis strains, Rhodotorula mucilaginosa, two Trichosporon pullulans strains and Yarrowia lipolytica were able to hydroxylate dibenzofuran. Three metabolites were identified by HPLC analysis: 3-hydroxydibenzofuran was in all the cases the most abundant isomer, and while 4-hydroxydibenzofuran was also common, 2-hydroxydibenzofuran was detected in very small quantities and with few species. In the R. glutinis and Y. lipolytica cultures a ring cleavage product was also found. While in the R. gluttinis assays the hydroxydibenzofuran was detected earlier, at 2 days' incubation time, in the other yeast experiments they were observed at the 4-5th incubation days with the maximum amounts at the 7th day. Our results confirmed the ability of autochthonous yeast species to hydroxylate dibenzofuran and to cleave the rings, and it is the first report for C. krusei, C. tenuis, P. anomala, P. haplophila and R. mucilaginosa. The ecological relevance of this study is based on the fact that dibenzofuran is a xenobiotic not easily transformed, so the catabolic activities observed in authochonous yeasts contribute to broadening the biodegradable substrate spectrum.     

Development of an optimal bacterial medium based on the growth inhibition assay with Vibrio fischeri.

Chronic toxicity level of chemicals to bacteria can depend on composition and concentration of medium ingredients. This was demonstrated by means of a growth rate inhibition test with the marine bacterium V. fischeri. In a minimal medium (following the validity criterion of achieving a least cell multiplication rate) containing only yeast extract as organic nutrient component, V. fischeri was to Cu2+ 11.9 times, to Hg2+ 3 times and to Zn2+ 2.8 times more sensitive than in the complete defined medium. Obviously yeast extract did not interfere greatly in the complexation mechanisms. The detection limits of the toxicity of Cd2+, 3,5-dichorophenol and nitrobenzene were not influenced by the substrate.     

Growth stimulation of Triticum aestivum seedlings under Cr-stresses by non-rhizospheric pseudomonad strains

Four chromium-resistant non-rhizospheric strains SPCr-1, SPCr-2, SPCr-3 and SPCr-4 (Pseudomonads), which were isolated from the effluents of an ICI paint factory and could tolerate 2-3 mg ml(-1) chromium in a minimal medium and 40 mg ml(-1) in a rich medium, were used to inoculate seeds of Triticum aestivum. Both inoculated and non-inoculated seeds were germinated and grown under different concentrations of chromium salts (K2CrO4, 0, 100, 250, 500; CrCl3, 0, 250, 500, 1000 microg ml(-1)). Germination and growth parameters were severely affected by chromium-salts. K2CrO4 had more drastic effects than CrCl3 treatments. Seedlings had a hard and brittle texture and showed symptoms of hypertrophy. Brown spots on leaves and stems were visible and the tips of leaves were bifurcated and curled. The root system was also impaired, ranging from a browning of the tip to complete destruction of cortical tissues. Under chromium-stress conditions, inoculated plants had significantly better germination and growth as compared to non-inoculated treatments. Bacterial growth enhancement of seedlings was associated with reduced chromium-uptake, increased auxin content and the formation of stress specific proteins. With bacterial inoculations, symptoms of chromium toxicity were reversed, especially at lower concentrations of chromium salts.     

Application of neutral electrolyzed water spray for reducing dust levels in a layer breeding house

Reducing airborne dust is an essential process for improving hen housing environment. Dust reduction effects of neutral electrolyzed water (pH 8.2) spray were investigated in a commercial tunnel-ventilated layer breeding house during production in northern China. A multipoint sampler was used to measure airborne dust concentration to study the dust reduction effects and distribution in the house. Compared with the control treatment (without spray), airborne dust level was reduced 34% in the 3 hr after spraying 216 mL m^?2 neutral electrolyzed water in the breeding house. The dust concentration was significantly higher during the periods of feed distribution (1.13 ± 0.13 mg m^?3) and artificial insemination (0.72 ± 0.13 mg m^?3) compared with after spray (0.47 ± 0.09 mg m^?3) and during lights-off period (0.29 ± 0.08 mg m^?3) in the three consecutive testing days (P < 0.05). The experimental cage area was divided into four zones along the length of the house, with zone 1 nearest to the evaporative cooling pad and zone 4 nearest to the fans. The air temperature, relative humidity, airflow rate, and dust concentration were measured at the sampling points of the four zones in 3 consecutive days and mortality of the birds for the duration of a month were investigated. The results showed that the air temperature, airflow rate, dust concentration, and number of dead birds increase from zone 1 to zone 4 in the tunnel-ventilated layer breeding house.

Implications: It is difficult to effectively reduce hen house airborne dust levels and limited information is available on airborne dust distribution in tunnel-ventilated hen houses. This work investigates (i) the application of neutral electrolyzed water spray for reducing dust in a layer breeding houses; (ii) dust concentration variations in 24-hr house operation; as well as (iii) the effects of location on dust concentrations. It was demonstrated that neutral electrolyzed water spray can be efficiently used for dust reduction in poultry houses. Further, a better understanding of the dust concentration variations in 24-hr house operation and in different spatial zones can contribute to bird housing environment management and poultry house design so as to improve bird health.     

Methionine auxotroph Escherichia coli growth assay kinetics in antibiotic and antifungal amended selective media

The objective of this work was to determine if Escherichia coli methionine bioassay characteristics were influenced by selective media amended with antibiotics and the antifungal compound cycloheximide. Bacterial cells were grown in minimal media with increasing concentrations of methionine and were incubated at 37 degrees C with vigorous agitation for 6 hours. Addition of antistatic agents to the media did not change the growth kinetic response (P>0.05) to methionine concentration (3.4 to 26.8 microM). This supports the utility of this strain as a methionine bioassay organism for feed and other environmental sources.     

Determination of PCDDs and PCDFs in different animal feed ingredients

As result of a study to control feedstuff, analyses were carried out to evaluate the contamination caused by PCDDs and PCDFs in different animal feed ingredients. Thirty two samples were selected, including ingredients of animal and mineral origin. For samples of mineral origin, some additives widely employed as binder and anticaking agents, such as bentonite, damoline, kaolin, magnesite, sepiolite and zeolite were selected. And, for ingredients of animal origin, samples of hemoglobin, animal fat, fish oil, fish meal and meat and bone meal were analyzed. The levels ranged from 0.52 to 9.08 pg WHO-TEQ/g fat for samples of animal origin, and from 0.05 to 460.59 pg WHO-TEQ/g for samples of mineral origin. The higher concentrations were observed for the kaolin samples that presented high levels of dioxin contamination.     

酵母菌处理马铃薯淀粉废水研究

马铃薯淀粉废水属高浓度废水,COD达到30 000 mg/L左右,BOD为15 000 mg/L左右,可生化性较好。针对废水中主要含有淀粉、蛋白质和可溶性纤维等成分,筛选分离出能降解这些有机成分的6种酵母。以废水为培养液分别培养这6种酵母及其混合菌,实验结果表明,各酵母菌株对该废水都有较好的降解效果,混合菌的处理效果要好于单个菌株。在连续流废水培养条件下,混合酵母活性和菌体量也较高,MLSS稳定在12 g/L左右,其COD去除率稳定在77%左右。     

Impact of desiccation and heat exposure stress on Salmonella tolerance to acidic conditions

In a recent study, the pH of commonly used Salmonella pre-enrichment media became acidic (pH 4.0 to 5.0) when feed or feed ingredients were incubated for 24 h. Acidic conditions have been reported to injure or kill Salmonella. In this study, cultures of four known feed isolates (S. montevideo, S. senftenberg, S. tennessee, and S. schwarzengrund) and four important processing plant isolates (S. typhimurium, S. enteritidis, S. infantis, and S. heidelberg) were grown on meat and bone meal and later subjected to desiccation and heat exposure to stress the microorganism. The impact of stress on the isolates ability to survive in acidic conditions ranging from pH 4.0 to 7.0 was compared to the non-stressed isolate. Cell injury was determined on xylose lysine tergitol 4 (XLT4) and cell death determined on nutrient agar (NA). When measured by cell death in non-stressed Salmonella, S. typhimurium was the most acid tolerant and S. heidelberg was the most acid sensitive whereas in stressed Salmonella, S. senftenberg was the most acid tolerant and S. tennessee was the most acid sensitive. The pH required to cause cell injury varied among isolates. With some isolates, the pH required for 50% cell death and 50% cell injury was similar. In other isolates, cell injury occurred at a more neutral pH. These findings suggest that the pH of pre-enrichment media may influence the recovery and bias the serotype of Salmonella recovered from feed during pre-enrichment.     

Phenolic content,antioxidant and antibacterial activity of selected natural sweeteners available on the Polish market

Seventeen natural sweeteners available on the Polish market were screened for total phenolic content, by the Folin-Ciocalteu method, and for antioxidant activity, using the ferric reducing antioxidant power (FRAP) assay and the 2,2′-Azinobis (3-ethylbenzthiazoline-6-sulphonic acid) radical cation decolorization assay (ABTS^·+). In addition, we analyzed antibacterial activities against Staphylococcus aureus strains: both those susceptible and those resistant to methicillin (MRSA). The results of the study showed that total phenolic content, antioxidant activity and antibacterial activity differ widely among different samples of sweeteners. Phenolic content, expressed as a gallic acid equivalent, ranged from 0 mg kg^?1 in white, refined sugar, xylitol and wheat malt syrup to 11.4 g kg^?1 in sugarcane molasses. Antioxidant activity was lowest in refined white sugar, xylitol, brown beet sugar, liquid fructose, and rape honey; it was average in spelt syrup and corn syrup, and highest in sugar cane, beet molasses, date and barley syrups. Despite the great variety of sweeteners, a strong correlation was noted between the concentration of phenolics and antioxidant properties, as determined by the ABTS^·+ method (r = 0.97) and the FRAP assay (r = 0.77). The strongest antibacterial activity was observed in sugarcane molasses, which was lethal to S. aureus strains at 2 and 4% concentrations in medium for susceptible and MRSA strains respectively. Other sweeteners kill bacteria in 6–15% solutions, whereas some did not show any antibacterial activities against S. aureus strains, even at 20% concentrations. Due to their high antioxidant and antibacterial activities, some of the tested sweeteners have potential therapeutic value as supporting agents in antibiotic therapy.     

Mercury in the Grisette,Amanita vaginata Fr. and soil below the fruiting bodies

This study examined the mercury concentration in the Grisette Amanita vaginata Fr. and soil below the fruiting bodies collected between 2000 and 2008 from the wild at seven distant sites across Poland. The Hg content in samples was determined by cold atomic absorption method (CV-AAS) at a wavelength of 253.7 nm. Mean Hg contents varied from 0.096 ± 0.052 to 0.48 ± 0.13 mg kg^?1 dry matter (dm) in caps (range, 0.043–0.73 mg kg^?1), from 0.047 ± 0.02 to 0.23 ± 0.07 mg kg^?1 dm (range, 0.028–0.47 mg kg^?1) in stipes, and in underlying soil were from 0.035 ± 0.018 to 0.096 ± 0.036 mg kg^?1 dm (range, 0.017 to 0.16 mg kg^?1). The median Qc/s values ranged from 1.2 to 2.2 (mean 1.2 ± 0.4 to 2.1 ± 0.5) indicating that Hg content in stipes was generally lower than in caps. This mushroom species has some potential to bioconcentrate Hg in the fruiting bodies, as the values of the bioconcentration factor (BCF) varied for the sites between 1.2 ± 0.6 to 11 ± 5 for caps and 0.61 ± 0.26 to 7.4 ± 3.9 for stipes. Also available literature data on Hg in A. vaginata are reviewed and discussed.     

Characteristics of organic acid profiles in 16 species of wild growing edible mushrooms

The aim of study was to determine 9 organic acids in nine aboveground and seven wood-growing wild edible mushroom species originated from an area under the direct influence of a busy trunk road in Poland. The organic acids in the extracts of samples were identified by reversed-phase column liquid chromatography (RPLC). The presented results show that all the mushroom species were characterized by high variation in the profile and content of the analyzed acids. Each of mushroom species contained oxalic acid, the profiles of the other acids strictly depended on mushroom species. Among aboveground species, the highest total content of organic acids was found in Lepista gilva (267.5 ± 26.6 mg g^?1 dry weight (DW)), while Laccaria amethystina was characterized by the lowest content (37.7 ± 6.5 mg g^?1 DW). Within wood-growing species, the highest content of organic acids was determined in Flammulina velutipes (171.9 ± 26.7 mg g^?1 DW), whereas the lowest content (34.2 ± 2.9 mg g^?1 DW) of the studied acids was observed in Grifola frondosa.