Growth of microorganisms in the pre-fermentation tanks in the production of ethanol

Our research was carried out to determine the plate count with a special observation Saccharomyces cerevisiae in the pre-fermenters cereal grains using the classical microscopic method. The cell counts were performed in the Bürker chamber. We followed changes in the plate count, number of Saccharomyces cerevisiae and changes during the yeast propagation in the mash. The mash would present only cultivated yeast Saccharomyces cerevisiae but may occur in a small number of other microorganism's types. Samples were taken during the propagation process in distillery factories. During this period, 30 samples of corn mash were examined. Samples were collected from two tanks during the fifteen generations. The total number of Saccharomyces cerevisiae was reduced and we got a number of unwanted microbiota. The statistical evaluation demonstrated that the growth of unwanted microbiota is directly related to the increase in the propagation of generation in corn mash. The maximum number of yeast cells was found in the twelfth generation 3.052 x 108 mL in the propagation tank. The total number of microorganisms in this generation was 3.149 x 108 mL and yeasts represent 96.92% of the total microbiota. In the sample B, 95.62% were Saccharomyces cerevisiae during the fifteenth generation. Our results showed that the optimal exchange of the yeast is in 15th generation. Subsequently, repeat the whole process but now with new yeast. These results confirmed our understanding of the relationship between Saccharomyces cerevisiae and contamination during the ethanol fermentation

Influence of essential oils on the growth of aspergillus flavus

This paper was focused on the determination of the inhibitory effect of selected essential oils on growth of ten isolates of Aspergillus flavus and their potential ability to produce mycotoxins in vitro by TLC method. The isolates were obtained from moldy bread of domestic origin. We followed the impact of five essential oils at 100% concentration - lemon, eucalyptus, oregano, sage and thyme. The effect of the essential oils we tested the gaseous diffusion method. We isolates grown on CYA (Czapek yeast extract agar), in the dark at 25 ±1 °C, 14 days. The diameter of colonies grown we continuously measured on the 3rd, 7th, 11th, and 14th day of cultivation. The results of the paper suggest that oregano and thyme essential oil had 100% inhibited the growth of all tested isolates of Aspergillus flavus. Lemon, eucalyptus and sage essential oil had not significant inhibitory effects on tested isolates Aspergillus flavus, but affected the growth of colonies throughout the cultivation. In addition to the inhibitory effect we witnessed the stimulative effect of lemon, eucalyptus and sage essential oil to some isolates. Together with the antifungal effect of essential oils, we monitored the ability of Aspergillus flavus isolates to produce mycotoxins - aflatoxin B1 (AFB1) and cyclopiazonic acid (CPA) in the presence of essential oils. Production mycotoxins we have seen in the last (14th) day of cultivation. Lemon and eucalyptus essential oil did not affect the production of mycotoxins. In the case of sage essential oil we were recorded cyclopiazonic acid production in three of the ten isolates from the all three repetitions, while neither isolate did not produced aflatoxin B1. The production of secondary metabolites was detected in all control samples. From the results we can say that oregano and thyme essential oil could be used as a natural preservative useful in the food industry

Antifungal activity of lemon, eucalyptus, thyme, oregano, sage and lavender essential oils against Aspergillus niger and Aspergillus tubingensis isolated from grapes

Today, it is very important to find out the protection of products of natural origin as an alternative to synthetic fungicides. The promising alternative is the use of the essential oils (EOs). Essential oils from plants have great potential as a new source of fungicide to control the pathogenic fungi.The main objective of this study was evaluation of the antifungal activity of lemon (Citrus lemon L.), eucalyptus (Eucalyptus globulus LABILL.), thyme (Thymus vulgaris L.), oregano (Origanum vulgare L.) sage (Salvia officinalis L.) and lavender (Lavandula angustifolia MILLER.) EOs against Aspergillus niger and Aspergillus tubingensis isolated from grapes and their ability to affect the growth. It was tested by using the vapor contact with them. At first both tested isolates were identified by using PCR method. Sequence data of 18S rRNA supported the assignment of these isolates to the genus Aspergillus and species A. niger (ITS region: KT824061; RPB2: KT824060) and A. tubingensis (ITS region: KT824062; RPB2: KT824059). Second, EO antifungal activity was evaluated. The effect of the EO volatile phase was confirmed to inhibit growth of A. niger and A tubingensis. EOs were diluted in DMSO (dimethyl sulfoxide) final volume of 100 μL. Only 50 μL this solution was distributed on a round sterile filter paper (1 x 1 cm) by micropipette, and the paper was placed in the center of the lid of Petri dishes. Dishes were kept in an inverted position. The essential oils with the most significant activity were determined by method of graded concentration of oils - minimum inhibitory doses (MIDs). The most effective tested EOs were oregano and thyme oils, which totally inhibited growth of tested isolates for all days of incubation at 0.625 μL.cm-3 (in air) with MFDs 0.125 μL.cm-3 (in air). Lavender EO was less active aginst tested strains (MIDs 0.313 μL.cm-3). The results showed that the tested EOs had antifungal activity, except lemon and eucalyptus. Sage EO was the only one which decelerated the radial growth of colony of both tested strains after all days of cultivation in comparison with a control sets. Our study provides the support that essential oils can be used to control plant pathogens such as A. niger and A. tubingensis

Mycobiota of spices and aromatic herbs

A total of 67 samples of spices and herbs were tested for mould contamination. From 50.7% of samples, moulds were not isolated. The most dominant genera were Aspergillus and Penicillium. Potential producers of mycotoxins Aspergillus spp. and Penicillium spp. were tested for the ability to produce some mycotoxins. Isolates of potentially toxinogenic species were found to produce various mycotoxins, namely alfatoxin B1 (Aspergillus flavus), cyclopiazonic acid (Aspergillus flavus), sterigmatocystin (Emericella nidulans), roquefortine C (Penicillium allii, P. chrysogenum, P. crustosum, P. expansum), penitrem A (P. crustosum) and patulin (P. expansum). Some of the tested isolates produce two mycotoxins: A. flavus (aflatoxin B1 and cyclopiazonic acid), P. crustosum (roquefortine C and patulin) and P. expansum (roquefortine C and patulin). None of the tested isolates of Aspergillus section Nigri screened, appeared to produce ochratoxin A. Totally 11 samples were analysed for the presence of aflatoxins and ochratoxin A. Aflatoxin B1 was found in 5 (45.5%) out of 11 samples analysed with levels ranging from 0.14 to 2.9 µg.kg-1. In one sample we detected aflatoxin G1.  Ochratoxin A was found in 3 samples (27.3%), with levels ranging from 2.2 to 5.19 µg.kg-1. No sample was contaminated by aflatoxins or ochratoxin A above the maximum admitted threshold established by the European legislation

Mycobiota of Slovak wine grapes with emphasis on aspergillus and penicillium species in the south Slovak wine region

The Southern Slovak wine growing region is warmest part of Slovakia and is suitable for cultivating the grapes for production of wines at high quality. From the eight vineyards were collected 8 samples of wine grapes (white 7, blue 1) during harvesting 2011, 2012 and 2013. The aim of this work was to gain more knowledge about mycobiota on grapes originating from Slovakia, to identify Aspergillus and Penicillium species according to their morphopogy and evaluate the presence of secondary metabolites (also including intracellular and extracellular mycotoxins) produced in in vitro conditions by thin layer chromatography method from fresh grape berries. Fifty wine grapes per bunch (approximately 7 - 8 berries per plate) that showed no symptoms were randomly selected on Dichloran Rose Bengal Chloramphenicol agar medium. The plates were then incubated aerobically at 25 ±1 °C for 5 to 7 days in the dark. Of these samples were identified 17 genera. One hundred percent of samples were colonies by the genus Penicillium and 75% by the genus Aspergillus. During the survey, 135 isolates belonging to 9 Penicillium species (P. aurantiogriseum, P. canescens, P. citrinum, P. crustosum, P. decumbens, P. expansum, P. funiculosum, P. chrysogenum and P. purpurogenum) and 26 isolates belonging to 3 Aspergillus species (A. clavatus, A. flavus and A. section Nigri) were isolated and identified from exogenous contamination. The main occurring penicillium species of the samples were P. expansum (37.5% Fr), followed P. citrinum, P. chrysogenum and P. crustosum (25% Fr). The main occurring aspergillus species of the samples were A. section Nigri (62.5%). Eight potentially toxigenic species were tested for their toxigenic ability. It was confirmed the production of various mycotoxins such as aflatoxin B1, citrinin, patulin, cyclopiazonic acid, penitrem A and roquefortin C. Out of 34 strains, 56% produced at least one mycotoxin

Species of genera Botrytis, Fusarium and Rhizopus on grapes of the Slovak origin

Our research was focused to identify the Botrytis, Fusarium and Rhizopus species from grapes of the Slovak origin. A further goal of the project was to characterized toxinogenic potential of chosen strains of species Fusarium. 50 samples of grapes, harvested in years 2011, 2012 and 2013 from various wine-growing regions were analyzed in this study. For the isolation of species the of direct plating method was used: a) surface-sterilized berries (using 1% freshly pre-pared chlorine) b) berries and c) damaged berries on DRBC (Dichloran Rose Bengal Chloramphenicol agar). For each analysis were used 50 berries (or all damaged berries from sample). The cultivation was carried at 25 ±1°C, for 5 to 7 days in dark. After incubation, the colonies of Botrytis, Fusarium and Rhizopus were transferred to identification media and after incubation strains were identified to species level.  Thirteen species of fusaria (F. acuminatum, F. avenaceum, F. culmorum, F. equiseti, F. graminearum, F. oxysporum, F. proliferatum, F. semitectum, F. solani, F. sporotrichioides, F. subglutinans F. tricinctum and F. verticilioides) were identified. Frequency of fusaria isolation was 92 %. Botrytis cinerea was determined from 86% samples and Rhizopus from 94%. Chosen strains of species of genus Fusarium were able to produce following mycotoxins: deoxynivalenol, T-2 toxin, HT-2 toxin and diacetoxyscirpenol in in vitro conditions as determinated by thin-layer chromatography. Thirty-two (68%) of tested isolates of Fusarium species were able to produce at least one mycotoxin

Colonization of grapes berries by Alternaria sp. and their ability to produce mycotoxins

Our research focused on identify the Alternaria species from grapes (surface sterilized berries and non-surface sterilized berries) of Slovak origin and characterize their toxinogenic potential in in vitro conditions. We analyzed 47 samples of grapes, harvested in years 2011, 2012 and 2013 from various wine-growing regions. For the isolation of species, the method of direct plating berries and surface-sterilized berries (using 1 % freshly pre-pared chlorine) on DRBC (Dichloran Rose Bengal Chloramphenicol agar) was used. For each analysis was used 50 berries. Only undamaged berries have been used for analysis. The cultivation was carried at 25 ±1°C, for 5 to 7 days in dark. After incubation, the colonies of Alternaria were transferred on PCA - potato-carrot agar and CYA - Czapek-yeast extract agar and cultured for 7 days at room temperature and natural light. A total 4 species-groups of the genus Alternaria were isolated from grapes berries: Alternaria alternata (1369 isolates), Alternaria arborescens (734 isolates), Alternaria infectoria (143 isolates), and Alternaria tenuissima (3579 isolates). According to European Union legislation mycotoxins produced by species genus Alternaria are not monitored in foods and food commodities. Mycotoxins such as alternariol and alternariol monomethylether are mutagenic and genotoxic in various in vitro systems. Selected strains were tested for production of altenuene, alternariol monomethylether and alternariol. In neither case of A. infectoria species-group isolates was confirmed the production of tested mycotoxins in in vitro conditions by TLC method. The ability to produce altenuene, alternariol monomethylether and alternariol in in vitro conditions was detected in isolates of Alternaria alternata, Alternaria arborescens and Alternaria tenuissima species-groups. Isolates of Alternaria alternata species-group (44 tested isolates) were able to produce altenuene (24 isolates), alternariol monomethyleter (42 isolates) and alternariol (43 isolates). Only one isolate did not produce any mycotoxins. Isolates of Alternaria arborescens species-group (38 tested isolates) were able to produce altenuene (24 isolates), alternariol monomethyleter (33 isolates) and alternariol (36 isolates). Only two isolates did not produce any mycotoxins. Isolates of Alternaria tenuissima species-group (87 tested isolates) were able to produce altenuene (42 isolates), alternariol monomethyleter (41 isolates) and alternariol (73 isolates). Thirteen isolates did not produce any mycotoxins

Effect of essential oils of Lamiaceae plants on the Rhizopus spp.

Normal 0 21 false false false EN-GB X-NONE X-NONE The aim of this study was to evaluate the fungicidal effect of eleven essential oils against six isolates of the genus Rhizopus. Isolates were obtained from various moldy foods (chestnut, bread, strawberry, nectarine, blackberry and cherry tomatoes).&nbsp; The essential oils used in this study were extracts of basil (Oscimum basilicum L.), hyssop (Hyssopus officinalis L.), lavender (Lavandula angustifolia MILLER.), marjoram (Origanum majorana L.), mint (Mentha piperita L.), oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), summer savory (Satureja hortensis L.), thyme (Thymus vulgaris L.) and wild thyme (Thymus serpyllum L.). Semi-quantitative composition of the essential oil samples was determined by gas chromatography coupled with mass spectrometry (GC-MS). The GC-MS analyses of the essential oils led to identification of 139 compounds, of which 49 were presented in &ge;1% amount in at least one essential oil. The antifungal activity of essential oils against the Rhizopus spp. was determined, using micro-atmosphere method (0.625 &mu;L.ml-1 of air), during 7 days. Seven essential oils: thyme, mint, summer savory, lavender, marjoram, oregano and wild thyme completely inhibited the growth of all isolates. Other essential oils have different effects on the growth of isolates. Basil essential oil stimulated growth of two isolates on the second day of cultivation. The growth of other isolates was, by contrast, inhibited by this essential oil in the same time of cultivation. Hyssop essential oil completely inhibited growth of two isolates, other 4 isolates were inhibited to fourth day of cultivation. In conclusion, certain essential oils are highly effective in vapour phase and can be used in another test of their antifungal activity and could be used in control of Rhizopus spp. or other fungal pathogens.&nbsp;</p

Wpływ pestycydów na aktywność mikroorganizmów w wybranych typach gleby na Słowacji

The aim of our work was to determine influence of pesticides on the soil respiration and the numbers of microorganisms (bacteria and their spores utilizing organic and inorganic nitrogen, actinomycetes, myxobacteria, Azotobacter chroococcum, microscopic fungi) in the three soil types (Haplic Chernozem, Haplic Luvisol, Cambisol). Cumulative values of basal CO2 production for 21 days represented from 595.62 mg o kg-1 to 1045.79 mg o kg-1 d.m. soil in tested samples of Haplic Chemozems and from 424.6 mg o kg-1 to 540.28 mg o kg-1 d.m. in tested samples of Haplic Luvisols and from 1789.84 mg o kg-1 to 2103.81 mg o kg-1 d.m. in tested samples of Cambisols. Potential CO2 production was higher (statistical significantly, p < 0.01) in all yariants (with addition of glucose, PVAL, herbicide and fungicide) than basal one. Stimulating effect of glucose addition was morę expressive in Haplic Lwisol than in Haplic Chernozem and Cambisol. Pesticides addition did not significantly affect on the decrease of numbers of bacterial vegetative forms in the soil types Haplic Chernozem and Cambisol. The insignificantly decrease was observed in the numbers of bacterial spores in the soil type Cambisol and in the numbers of microscopic fungi only in the soil type Haplic Chernozem.Celem naszych badań było określenie wpływu pestycydów na oddychanie gleby oraz liczebność mikroorganizmów (bakterii oraz ich spór zużywających organiczny i nieorganiczny azot, promieniowców, myxobakterii, Azotobacter chroococcum, mikroskopijnych grzybów) w trzech typach gleby (czarnoziemu, płowej, brunatnoziemnej). W glebie typu Haplic Chernozem kumulatywne wartości podstawowej produkcji C02 w ciągu 21 dni wynosiły od 595.62 do 1045.79 mg o kg-1 s.m. (suchej masy gleby). W glebach Haplic Luvisols wartości te wynosiły od 424.6 do 540.28 mg o kg-1 s.m., a w glebach typu Cambisol od 1789.84 do 2103.81 mg o kg-1 s.m. Wartości podstawowej produkcji CO3 były mniejsze od potencjalnej produkcji CO2 (różnice istotne statystycznie przy p < 0,01) we wszystkich wariantach eksperymentu (dodatki glukozy, PVAL, herbicydu, fungicydu). Stymulujący wpływ glukozy byt bardziej wyraźny w glebie typu Haplic Luyisol niż w glebie Haplic Chernozem i Cambisol. Pestycydy nie wpłynęły w sposób istotny statystycznie na zmniejszenie liczebności wegetatywnych form bakterii w glebach typu Haplic Chernozem i Cambisol. Zaobserwowano nieistotny statystycznie spadek liczby spór bakteryjnych w glebie typu Cambisol oraz liczebności mikroskopijnych grzybów w glebie typu Haplic Chernozem

FREQUENTED SPECIES OF FIELD FUNGI ON WHEAT AND THEIR POTENTIAL PRODUCTION OF TOXIC METABOLITES

<span style="font-family: 'Times New Roman'; font-size: small;"><span style="font-size: 13px;"><span style="font-size: medium;"><p>&nbsp;</p><p style="text-align: justify; background: white;"><span style="font-size: 10.0pt; color: black;">The aim of this study was to monitor isolates of&nbsp;<em>Alternaria</em>&nbsp;and&nbsp;<em>Fusarium&nbsp;</em>species, isolated from Slovak wheat grains in 2006 - 2008, for ability to produce mycotoxins and to estimate a potential contamination risk of wheat grains by mycotoxins. Toxinogenity of isolates was analyzed by means of thin layer chromatography (TLC) and liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). A&nbsp;total of 302&nbsp;<em>Alternaria</em>&nbsp;species (<em>A. alternata</em>,&nbsp;<em>A. arborescens</em>,&nbsp;<em>A. infectoria</em>,&nbsp;<em>A. tenuissima</em>) were tested by TLC method and a total of 238&nbsp;<em>Fusarium&nbsp;</em>species (<em>F. acuminatum</em>,&nbsp;<em>F. avenaceum</em>,&nbsp;<em>F. crookwellense</em>,&nbsp;<em>F. culmorum</em>,&nbsp;<em>F. equiseti</em>,&nbsp;<em>F. graminearum</em>,&nbsp;<em>F. langsethiae</em>,&nbsp;<em>F. oxysporum</em>,&nbsp;<em>F. poae</em>,&nbsp;<em>F. proliferatum</em>,&nbsp;<em>F. semitectum</em>,&nbsp;<em>F. solani</em>,&nbsp;<em>F. sporotrichioides</em>,&nbsp;<em>F. subglutinans</em>,&nbsp;<em>F. tricinctum</em>,&nbsp;<em>F. verticillioides</em>) were analyzed by TLC as well as LC/MS/MS method. All&nbsp;<em>Alternaria</em>&nbsp;sp. strains, excepting&nbsp;<em>A. infectoria</em>strains, showed high potention to produce altenuen, alternariol and alternariol monomethylether. None of&nbsp;<em>A. infectoria</em>species strains produced any mycotoxins analyzed in this study.&nbsp;<em>Fusarium</em>&nbsp;sp. strains demonstrated, according to toxicology specificity, ability to produce trichothecenes (deoxynivalenol, diacetoxyscirpenol, fusarenone X, HT-2 toxin, monoacetoxyscirpenol, neosolaniol, nivalenol, T-2 toxin), fumonisins, zearalenones, moniliformine and rarely mentioned toxins as aurofusarine, beauvericine, enniatins, equisetin and chlamydosporol. High potential production of mycotoxins and wide spectrum of toxic metabolites represent high risk of toxins production in real field conditions.<br /><br /><span style="font-size: small; color: #111111; font-family: 'Times New Roman', serif;"><strong>doi:10.5219/108</strong></span></span></p><p>&nbsp;</p></span></span></span