Safety Evaluation of an Intranasally Applied Cocktail of Lactococcus lactis Strains in Pigs.

Three Lactococcus lactis strains from the nasal microbiota of healthy pigs were identified as candidates for reducing MRSA in pigs. The safety of nasal administration of a cocktail of these strains was examined in new-born piglets. Six days pre-farrowing, twelve sows were assigned to the placebo or cocktail group (n = 6/group). After farrowing, piglets were administered with either 0.5 mL of the placebo or the cocktail to each nostril. Health status and body weight were monitored at regular time points. Two piglets from three sows/treatment group were euthanised at 24 h, 96 h and 14 d after birth, and conchae, lung and tonsil samples were collected for histopathological and gene expression analysis. Health scores were improved in the cocktail group between d1-5. Body weight and daily gains did not differ between groups. Both groups displayed histological indications of euthanasia and inflammation in the lungs, signifying the findings were not treatment related. The expression of pBD2, TLR9 and IL-1ß in the nasal conchae differed between groups, indicating the cocktail has the potential to modulate immune responses. In summary, the L. lactis cocktail was well tolerated by piglets and there was no negative impact on health scores, growth or lung histopathology indicating that it is safe for administration to new-born piglets.

The Utilisation of Acrylamide by Selected Microorganisms Used for Fermentation of Food.

Acrylamide (AA) present in food is considered a harmful compound for humans, but it exerts an impact on microorganisms too. The aim of this study was to evaluate the impact of acrylamide (at conc. 0-10 µg/mL) on the growth of bacteria (Leuconostoc mesenteroides, Lactobacillus acidophilus LA-5) and yeasts (Saccharomyces cerevisiae, Kluyveromyces lactis var. lactis), which are used for food fermentation. Moreover, we decided to verify whether these microorganisms could utilise acrylamide as a nutritional compound. Our results proved that acrylamide can stimulate the growth of L. acidophilus and K. lactis. We have, to the best of our knowledge, reported for the first time that the probiotic strain of bacteria L. acidophilus LA-5 is able to utilise acrylamide as a source of carbon and nitrogen if they lack them in the environment. This is probably due to acrylamide degradation by amidases. The conducted response surface methodology indicated that pH as well as incubation time and temperature significantly influenced the amount of ammonia released from acrylamide by the bacteria. In conclusion, our studies suggest that some strains of bacteria present in milk fermented products can exert additional beneficial impact by diminishing the acrylamide concentration and hence helping to prevent against its harmful impact on the human body and other members of intestinal microbiota.

Dried Biomass of Arthrospira platensis Inhibits Growth of Aureobasidium pullulans LW14 and Some Bacteria When Added to Unpasteurised Apple Juice.

The main goal was to evaluate if dried cyanobacterium (Arthrospira platensis) biomass added to unpasteurised apple juice could inhibit growth of fungi dominant in apples and which fraction of cyanobacterium biomass contributed to this phenomenon. A. platensis biomass, its protein and/or polysaccharide fraction were added to the sterilised apple juice inoculated with Aureobasidium pullulans LW14 and stored at 4 °C for 96 h. Samples were tested against number of fungi and selected physical-chemical parameters. In the last research stage, protein fraction was added to the unpasteurised apple juice inoculated with A. pullulans LW14 to test its potency against fungi, lactic acid bacteria and acetic acid bacteria. When A. platensis biomass was added to the sterilised apple juice (1.15% w/v), it effectively inhibited growth of A. pullulans LW14 and the metabolism of all analysed sugars (glucose, sucrose and fructose). Protein fraction added to the sterilised apple juice contributed significantly to mycostatic properties of A. platensis. When protein fraction was added to unpasteurised apple juice, the same conclusions were obtained, however, except for inhibiting growth of A. platensis LW14, it inhibited growth of some bacteria.

Saccharomyces bayanus Enhances Volatile Profile of Apple Brandies.

Qualitative and quantitative profiles of volatiles in alcoholic beverages depend mainly on the quality of raw materials, yeasts used for fermentation, and processing technique. Saccharomyces bayanus is a yeast species which is not commonly used for the production of alcoholic beverages, but it is able to produce volatiles that add desirable aroma. Since there is little information regarding the application of that microorganism for the production of apple brandies and how it affects volatile profile of finished products, we decided to address that issue. The aim of the study was to determine the impact of S. bayanus on the profile of volatile compounds and sensory properties of apple spirits obtained from three apple cultivars (Topaz, Rubin, and Elise) in comparison to spirits obtained from fermentation carried out spontaneously or with Saccharomyces cerevisiae. Obtained brandies were analysed using gas chromatography-flame ionization detector (GC-FID), solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and sensorially. In our study, brandies produced from musts fermented by S. bayanus demonstrated the highest concentration of ethyl esters and increased concentrations of isoamyl acetate, 2-phenylethyl acetate, ethyl palmitate and hexanol. Moreover, our results support the hypothesis that non-Saccharomyces yeasts which are present during spontaneous fermentation and demonstrate higher ß-glucosidase activities enhance aroma of alcoholic beverages through releasing aroma compounds from glycosidic forms, e.g., α-phellandrene, (E)-ß-fanesene, (Z,E)-α-farnesene, α-farnesene, and farnesol. Considering results obtained in sensory analysis, we proved that S. bayanus is suitable for the production of apple brandies, improving their flavour. Brandies obtained from musts fermented by S. bayanus obtained the highest average range for "overall note" parameter in sensory analysis.

Examination of novel Aureobasidium pullulans isolates dominating apple microflora and assessing their potential for apple juice spoilage.

There is very little up to date information regarding apple microflora so in the current study we decided to address that issue and assess whether dominant fungi which reside in fruit might spoil apple juice. Microorganisms were isolated from apples of Koksa Górska harvested in the middle of October in 2016 and 2017. Identification of isolates was based on the sequencing of ribosomal DNA. Some isolates were characteristic for a particular year but in both years apple microflora was dominated by Aureobasidium pullulans. Based on phylogenetic analysis it was stated that only one isolate (LW81) was closely related to strains which are already described in available databases. All other isolates collected in the current study differed significantly from sequences stored in databases, tending to form a common cluster. It was possible to predict secondary structure of ITS2 region only for the isolate LW81, while we managed to establish the length and location of 5.8S gene in Rfam database for all sequences. A. pullulans is known exopolysaccharide producer so obtained microorganisms were tested for their ability to synthesise those substances on Czapek-Dox agar. The strain which proved to be the most significant exopolysaccharide producer (isolate LW14) was inoculated in the sterilised apple juice at three different initial cell number (100, 1000 and 10,000 cfu/ml) and subjected to pasteurisation. In all cases pasteurisation eliminated fungal growth effectively, therefore A. pullulans strains should not pose any risk to the quality of pasteurised apple juices.

Application of principal component analysis for the optimisation of lead(II) biosorption.

Current study was focused on optimising lead(II) biosorption carried out by living cells of Arthrospira platensis using Principal Component Analysis. Various experimental conditions were considered: initial metal concentration (50 and 100 mg/l), solution pH (4.0, 4.5, 5.0, 5.5) and contact time (10, 20, 30, 40, 50 and 60 min) at constant rotary speed 200 rpm. It was found that when the biomass was separated from experimental solutions by the filtration, almost 50% of initial metal dose was removed by the filter paper. Moreover, pH was the most important parameter influencing examined processes. The Principal Component Analysis indicated that the most optimum conditions for lead(II) biosorption were metal initial concentration 100 mg/l, pH 4.5 and time 60 min. According to the analysis of the first component it might be stated that the lead(II) uptake increases in time. In overall, it was found to be useful for analysing data obtained in biosorption experiments and eliminating insignificant experimental conditions. Experimental data fitted Langmuir and Dubinin-Radushkevich models indicating that physical and chemical absorption take place at the same time. Further studies are necessary to verify how sorption-desorption cycles affect A. platensis cells.

The immobilization of Arthrospira platensis biomass in different matrices--a practical application for lead biosorption.

The biosorption of lead by cyanobacteria (Arthrospira platensis) immobilized in different matrices was studied. This was the first time that sodium alginate, silica gel and agarose beads have been used for the removal of lead from solutions of the metal in concentrations ranging from 50 to 500 mg/L. The effect of pH in the range 4.0 to 5.5 on lead removal was also investigated. For the best biosorbent chosen from those mentioned above, lead biosorption in samples of real wastewater was examined. The maximum biosorption capacities (q) for cells immobilized in alginate, agarose and silica gel were 424.99 ± 16.73, 272.66 ± 7.54 and 2.68 ± 0.25 mg Pb/g dry matter of biosorbent, respectively. The initial pH of the solution as well as initial Pb(II) concentration had an influence on metal uptake. The highest lead sorption by alginate and agarose immobilized cells was reported at pH 5 and at initial lead concentration of 500 mg/L, while sorption by silica immobilized cells was the most effective at pH 4 and initial concentration of 100 mg Pb(II)/L. The reported lead uptake (about 165 mg/g dry weight) by cyanobacterial cells entrapped in sodium alginate was higher in real wastewater than in simulated wastewater of the same initial lead concentration. The results revealed that this new biosorbent system can be a promising candidate for eliminating Pb(II) from wastewater, and more detailed research should be carried out.