Amounts Of Volatile Fatty Acids Research Articles

E-nose analysis of milk to detect the inclusion of hydroponic barley forage in the buffalo diet

This study explores the use of an electronic nose (E-nose), equipped with ten metal oxide semiconductor thin-film sensors, to detect raw milk samples from buffaloes fed hydroponic barley forage as a substitute for maize silage. 108 samples were collected on three different days, from three groups of twelve Italian Mediterranean buffaloes each. The control group (C) was fed a diet based on maize silage, which in the other groups was replaced by hydroponic forage at 50 % (LH group) and 100 % (HH group). The data pattern from the E-nose sensor responses data was analysed using linear discriminant analysis (LDA) and principal component analysis (PCA) as pattern recognition methods, to investigate the discrimination capability of the sensor array. Confusion matrix, obtained from LDA, correctly classified C, LH and HH milk at 90 %. Solid-phase microextraction with gas chromatography–mass spectrometry revealed that C samples had the highest total level of volatile organic compounds, particularly ketones, volatile fatty acids and esters, while HH had the lowest quantity of volatile fatty acids and higher amounts of p-cresol, 1-octen-3-ol and dimethyl sulfone. This has resulted in a greater response intensity of most E-nose sensors for C, such as W1S, W2S, W3S and W6S, which react to high concentrations of broad-range and aliphatic compounds. E-nose proves effective in rapidly identifying hydroponic forage in buffalo diets.

Optimization of biomethane production from lignocellulosic biomass by a developed microbial consortium

Biomethane production from lignocellulosic biomass via anaerobic digestion (AD) is a promising avenue for bioenergy. However, maximizing biomethane yield using developed microbial consortium (DMC) remains a complex challenge. This study aims to elucidate the comparative efficacy of a purposefully DMC under controlled conditions for AD of kallar grass (KG), rice husk (RH) and wheat residue (WR). The DMC encompasses Bacteroidetes, Firmicutes, Proteobacteria, Euryarchaeota, and Chloroflexi, with methanogens representing 14.6% of the community. Thorough physico-chemical characteristics and ultimate analyses provided comprehensive insights into compositions and bio-methane potentials prediction of biomasses. The digester revealed higher biomethane potentials (BMPs) with short lag phase and retention time and showed methane content of 61–64.6% during the first week of AD. The amount of volatile fatty acids (VFA) did not exceed the threshold levels, which facilitated the smooth operation of AD. The BMP was found highest in KG (289.7 mL/g VS), followed by RH (283.3 mL/g VS), and WR (269.7 mL/g VS) which is significantly higher than previously reported studies. The modified Gompertz model showed the best fit, followed by logistic and transference function models. The observed results signpost the tremendous potential of waste biomass particularly KG, RH and WR to produce biomethane by DMC. This study provides crucial insights for optimizing BMP emphasizing the promising prospects of KG, RH, and WR for sustainable bioenergy applications.

Effect of different doses of cobalt on rumen digestion in cattle

Optimization of mineral nutrition is a necessary measure to maintain high productivity of beef cattle which often lack minerals in their feed. The innovative base in this case can be ultrafine particles of essential elements characterized by high bioavailability in a small dose. The effect of ultrafine Co3O4 particles on the digestibility of dry matter of feed in the in vitro system (artificial rumen), the amount of volatile fatty acids, nitrogen forms (total, non-protein, ammonia, urea, protein) and on the amino acid composition (arginine, lysine, methionine, alanine, glycine) of animal rumen fluid was studied. The research was conducted in 2023. Cattle of the Kazakh white-headed breed aged 11-12 months with an average weight of 265-275 kg were used as an object of research. It was found that in in vitro studies, dry matter digestibility of feed was 9.0% higher at a concentration of 0.36 g/mL of Co3O4 ultrafine particles. Analysis of volatile fatty acid concentration showed that this dosage increases acetic acid, propionic acid, butyric acid, valerianic acid, and caproic acid. The introduction of ultrafine Co3O4 particles increased the content of protein nitrogen and total nitrogen in the experimental animals, indicating the intensification of rumen microbiocenosis. At introduction of ultrafine Co3O4 particles, shifts in the amino acid composition of the rumen contents were observed, which may be caused by the changes in the nature of nitrogenous substances transformation in the digestive tract. It is concluded that the use of ultrafine Co3O4 particles has a positive effect on the digestive processes in the rumen.

Optimization of biogas production from anaerobic co-digestion of fish waste and water hyacinth

Many fresh water bodies face a great challenge of an invasive weed called water hyacinth (WH) which has great impacts on the environment, ecology, and society. Food and Agriculture Organization (FAO) estimates that over nine million tons of Fish wastes (FW) are thrown away each year. The fish waste generated poses environmental and health hazards because in most cases it is either disposed into pits or discarded onto the open grounds. Both WH and FW are potential substrates for biogas production. However, utilization of FW substrate alone has a limitation of producing a lot of amounts of volatile fatty acids (VFAs) and ammonia. Their accumulation in the digester inhibits substrate digestion. Consequently, as stand-alone it is not suitable for anaerobic digestion (AD). This can be overcome by co-digestion with a substrate like WH which has high carbon to nitrogen (C/N) ratio prior to biodigestion. Experimental variable levels for biogas were substrate ratio (WH:FW, 25–75 g), inoculum concentration (IC, 5–15 g/250 mL), and dilution (85–95 mL). Design-Expert 13 was used for optimization and results analysis. Response surface methodology (RSM) was used to examine the effects of operating parameters and identify optimum values for biogas yield. Optimum values for maximum biogas with the highest methane yield of 68% were found to be WH:FW ratio, 25:75 g, 15 g of IC, and 95 mL for dilution. The yield was 16% and 32% greater than FW and WH mono-digestion, respectively. The biogas yield was expressed as a function of operating variables using a quadratic equation. The model was significant (P < 0.05). All factors had significant linear and quadratic effects on biogas while only the interaction effects of the two factors were significant. The coefficient of determination (R2) of 99.9% confirmed the good fit of the model with experimental variables.

Maca (Lepidium meyenii): In Vitro Evaluation of Rumen Fermentation and Oxidative Stress

The aim of this study was to investigate the chemical composition of three maca (Lepidium meyenii Walp.) ecotypes (yellow, black, and red) and their in vitro fermentation characteristics and antioxidant effects on cow rumen liquor. The three ecotypes were added to a total mixed ratio (TMR) in different doses (0, 150, and 300 mg/g) and incubated in vitro under anaerobic conditions for 120 h. Methane production was recorded after 24 h of incubation. Antioxidant status and degree of lipid peroxidation were also evaluated after 24 and 120 h of incubation with the fermentation liquor. An analysis of the chemical composition showed high concentrations of non-structural carbohydrates in all maca ecotypes, particularly in the yellow ecotypes. Moreover, despite an increase in gas production, it seems that the TMR supplemented with each maca ecotype, particularly at the highest dose, increases the amount of volatile fatty acids and reduces methane production. Finally, the addition of maca can induce an antioxidant effect. Our findings suggest that the three ecotypes of maca are rich in non-structural carbohydrates which affect the in vitro fermentation kinetics and reduce methane production.

Integrated omics analysis on the bacterial community in the anaerobic digestion of chicken manure materials in biogas production farm

The overall effectiveness of anaerobic digestion is affected by the initial three phases as a result of substrates created for the methanogens to take in. In this study, the bacterial composition of the various chambers in the anaerobic digestion of chicken manure was investigated. Diversity of the microbial community for chicken manure was relatively simpler, consisting mainly of Lactobacillus, compared to the main digestion chambers with a more complex community. Chicken manure only has hydrolysis phase occurring, while the main digesters have the first three phases of anaerobic digestion concurrently occurring. A comparison of the metagenomics versus metaproteomics analysis revealed that the main difference was in the percentage of unknown microorganisms. The quantity of volatile fatty acids detected in each respective chamber suggested the effectiveness of the microorganisms in assimilating the metabolites. Successful integration of these study modes would present a better understanding on anaerobic digestion of complex systems.

Fermented cottonseed and rapeseed meals outperform soybean meal in improving performance, rumen fermentation, and bacterial composition in Hu sheep.

This study examined the effects of substituting cottonseed meal (CSM) or rapeseed meal (RSM) for soybean meal (SBM) on Hu sheep performance, rumen fermentation, and bacterial composition. 51 four-month-old indigenous male Hu sheep with starting body weights of 22.51 ± 2.84 kg and similar origins were randomly assigned to three treatments; (1) non-fermented total mixed ration (TMR) with SBM (CK), (2) fermented TMR containing CSM (F-CSM group), and (3) fermented TMR containing RSM (F-RSM group). The three groups' intake of dry matter differed significantly (p < 0.05). In terms of average daily gain, the F-RSM group outperformed the CK and F-CSM groups (p < 0.05). The pH of the rumen was substantially lower in the CK group than in the F-CSM and F-RSM groups (p < 0.05), and the F-CSM group had greater amounts of volatile fatty acids (VFA) than the F-RSM and CK groups. In comparison to the CK group, the microbial crude protein yield was significantly higher in the F-CSM and F-RSM groups (p < 0.05). The F-CSM group significantly outperformed the F-RSM group of pepsin and cellulose enzyme activity (p < 0.05). The relative abundance of Bacteroidetes was greater in the CK and F-RSM groups compared to the F-CSM group (p < 0.05). In comparison to the other groups, Firmicutes were less abundant in the CK group (p < 0.05). Prevotella was present in a higher relative abundance in the F-CSM and F-RSM groups than in the CK group (p < 0.05). Prevotella was greater in relative abundance in the F-CSM and F-RSM groups than in the CK group (p < 0.05). The relative abundances of Veillonellaceae_UCG-001 and Lachnospiraceae_XPB1014 correlated with rumen butyric acid content and NH3-N content (p < 0.05). Gene function prediction revealed that replacing SBM with F-CSM or F-RSM in the diet of Hu sheep can promote glycan biosynthesis and metabolism. The replacement of F-CSM and F-RSM for SBM has an influence on the richness and diversity of rumen bacteria at the phylum and genus levels. Replacement of SBM with F-CSM increased VFA yield and further promoted the performance of Hu sheep.

Development of biotechnology for cheese having a noble mould: A relationship between biochemical processes and product quality

Since late 2014, following the embargo, a significant reduction in cheese import, including mould cheese, has been observed. Developing new cheese technologies comprise therefore an urgent task for the milk industry. The cheeses ripened using noble mould represent a wholesome product, rich in protein, which contains many essential amino acids, beneficial for strengthening the walls of blood vessels and reducing angiasthenia. The microorganisms in the cheese starter culture create favourable conditions for healthy microflora in the gastrointestinal tract, preventing fermentation and meteorism. The high content of vitamin B12 in these cheeses has a positive effect on the central nervous system. Any production must be economically viable, lowering the production costs. In order to increase income, and consequently the profitability of production, the method of cheese ripening using a noble mould, obtained from a mixture of whole milk and secondary protein-carbohydrate raw materials, was proposed. The influence of the type of protein-carbohydrate raw material, yeast and mould on the physicochemical and organoleptic properties of the product was investigated. The optimal ratio of raw materials (milk:buttermilk) for cheese production was determined. The relative composition of nitrogen fractions and the presence and amount of volatile fatty acids in the proposed product were also examined. It was shown that proteolysis and lipolysis processes were more intensive in the experimental cheeses produced using a noble mould, resulting in the improvement of organoleptic characteristics of the finished product. The resulting soft cheese having unique characteristics and a tangy mushroom flavour can be recommended for production in cheese factories.

Solid‐Liquid separation through sieve mesh for enhancing biogas production in a swine farm

Anaerobic digestion is one of the most efficient methods for pig manure management. In this study, methane measurement of a liquid fraction obtained from 0.1 mm sieve mesh filtration and raw pig manure was conducted, and the corresponding dynamic evolution of metabolites and microbial community structure was investigated. The results showed that the liquid fraction filtered through a 0.1 mm sieve mesh gave a maximum methane production yield of 468.13 mL-CH4/g-VSadded, 4.50-times higher than raw pig slurry after 60 days. This result indicates that the 0.1 mm sieve filtration effectively provided an appropriate concentration of biodegradable compounds for high methane production in the slurry. Interestingly, the filtrates from 0.1 mm sieve mesh initially produced a high amount of volatile fatty acid, which later considerably decreased the concentrations of acetic and butyric acids on the day when the methane concentration increased. The metabolite results were consistent with the microbial community analysis, which revealed an increase in the populations of acid-producing bacteria and archaea in the filtrates from 0.1 mm sieve mesh samples as compared to the non-filtered samples. These findings indicate that the filtrates from a 0.1 mm sieve mesh sample contained a greater proportion of cooperative producers of acid and methane than the non-filtered samples. In addition, the techno-economic analysis demonstrated that this method would be economically viable when applied to a large-scale system (100 tons of pig slurry) since it can yield a substantial profit margin of 1,847,723 $/year and a return on investment of 25%.

Feasibility of nanofiltration process for high efficient recovery and concentrations of food waste-derived volatile fatty acids

Various methods exist for the recovery of volatile fatty acids from organic mixed waste effluents, and among them, the membrane filtration process holds a great promise over other recovery methods due to their simplicity, sustainability and high efficiency. Hence, in this study, nanofiltration experiments were carried out using two commercial nanofiltration membranes of 200–300 Da and 300–500 Da under various pH (4, 5.4, 7 and 9) at constant pressure (15 bar) and temperature of 20-21 °C in order to achieve a higher amount of volatile fatty acids from the real mixed food waste-based effluent. Results showed that solution pH plays an important role in the physicochemical parameters such as total solids removal rate was above 80 % at pH 4, chemical oxygen demand, ammonia and phosphorus removed to some extent at pH 9. Subsequently, the concentration and recovery percentages of volatile fatty acids increased with solution pH 9; in particular, lower molecular weight cut-off membrane, i.e., 200–100 Da, appeared to be more effective with an increased concentration of total volatile fatty acids (16.94 g L−1) and recovery percentage above 90 % at pH 9. Membrane performance was also evaluated and correlated with recovery performance in terms of permeate flux reduction at lower pH. An important finding of this study was the concentration and recovery percentages of volatile fatty acids reached around 96 % after 3rd cycle by conducting a repeated sequencing nanofiltration process, which was identified as a promising option to enhance the recovery percentages of volatile fatty acids.

Comparison of Bacterial and Archaeal Microbiome in Two Bioreactors Fed with Cattle Sewage and Corn Biomass

The bacterial and archaeal communities of two full-scale biogas producing plants (P1 and P2), associated with a 999 kW cogeneration unit, both located in North Italy, were analyzed at start up and fully operating phases, by means of various molecular approaches: (i) Automated Ribosomal Intergenic Spacer Analysis; (ii) cloning and sequencing of PCR amplicons of archaeal genes 16Srrna and mcrA; (iii) 16S rDNA high throughput next generation sequencing. P1 and P2 use the same technology and both were fed with cattle manure and corn silage. During the study of P1 also the post digester (fed with pig manure) was analyzed. The aim of this research was to characterize the bacterial and archaeal communities in two very similar plants to profile the core microbiota. The results of this analysis highlighted that the two plants (producing comparable quantities of volatile fatty acids, biogas, and energy) differed in anerobic microbiota (Bacteria and Archaea). Notably the methanogenic community of P1 was dominated by the strict acetoclastic Methanosaeta (Methanothrix) (up to 23.05%) and the unculturable Candidatus Methanofastidiosum (up to 32.70%), while P2 was dominated by the acetoclastic, but more substrate-versatile, Methanosarcina archaeal genus (49.19%). The data demonstrated that the performances of plants with identical design, in similar operating conditions, yielding comparable amount of biogas (average of 7237 m3 day−1 and 7916 m3 day−1 respectively for P1 and P2), VFA (1643 mg L−1 and 1634 mg L−1) and energy recovery (23.90–24 MWh day−1), depend on the stabilization of effective and functionally optimized methanogenic communities, but these communities are taxonomically different in the two biodigesters.

A high-starch vs. high-fibre diet: effects on the gut environment of the different intestinal compartments of the horse digestive tract

BackgroundHorses are often fed high amounts of starch in their diets despite the well-established benefits of a fibre-based diet to promote gut health and animal welfare. The aim of the present study was to compare the effects of two different diets – one based on high amounts of starch (HS) vs. one base on high amounts of fibre (HF) – on specific parameters of the gut environment across different intestinal compartments of the horse digestive tract. To this end differences in the gastrointestinal environment between HS vs. HF fed horses were assessed in terms of dry matter, organic matter and ash content; the particle size distribution and volatile fatty acid composition were also investigated.ResultsNineteen Bardigiano horses of 14.3 ± 0.7 months of age and destined to slaughter were divided into two group pens – one fed with high amounts of starch (HS; n = 9; 43% hay plus 57% starch-rich pelleted feed); vs. fed with high amounts of fibre (HF; n = 10; 70% hay plus 30% fibre-rich pelleted feed). Horses fed HS diet presented a higher dry matter content in the right dorsal colon. Moreover, they showed a higher organic matter and ash content in the sternal flexure, pelvic flexure, right dorsal colon and rectum. In these latter intestinal compartments, horses fed a HS diet also showed a higher proportion of particles retained on an 8 mm sieve and a higher proportion of particles that washed through the finest sieve (< 1 mm). Moreover, the total amounts of volatile fatty acids as well as valeric acid were found to be significantly higher in horses fed the HS vs. HF diet.ConclusionsA high-starch diet causes significant changes in the horse gut environment. We observed an increase in the dry matter content in the right dorsal colon, as well as reduced particle sizes and an increase in the production of valeric acid in all the gut compartments studied. High-starch diets should be avoided in favour of fibre-based diets with the goal of safeguarding gut health in horses.

Enzymatic Pretreatment Improved the In Vitro Ruminal Degradability of Oil Palm Fronds

This study aims to increase the in vitro ruminal degradability of oil palm fronds (OPFs) through enzymatic pretreatment. The isolated fungi were selected based on their lignocellulosic degrading enzyme activities. Eleven fungi were successfully isolated, and their enzyme activities were evaluated. Three fungi, F1, F2 and F4 were selected, and they were identified as Trichoderma harzianum MK027305, Trichoderma harzianum MK027306 and Fusarium solani MK027309, respectively. The highest total gas and methane production was produced when OPFs were pretreated with an enzyme extract from 15 and 30 days of solid-state fermentation of T. harzianum MK027305 and T. harzianum MK027306, respectively. Meanwhile, OPFs pretreated with an enzyme extract from F. solani MK027309 after 45 days of solid-state fermentation produced the highest amount of volatile fatty acids. The pretreatment using the enzymes extracted from 45 days of solid-state fermentation of F. solani MK027309 increases the apparent rumen degradable carbohydrate (ARDC) by 35.29% compared to unpretreated OPF. This study showed that pretreatment of the OPFs using selected fungi’s enzymes increases the volatile fatty acid production and in vitro ruminal degradability of OPF, hence improving livestock production via increased utilization of agricultural by-products with minimal impact on the production cost.

Producing of ecologically safe food raw materials based on new system of calf rearing

The productivity and physiological state of young cattle in the post-dairy period were studied. The use of whole milk substitute in feeding calves contributed to the strengthening of metabolic processes in the animal body in the post-dairy period, as evidenced by an increase in the amount of volatile fatty acids in the scar fluid by 6.8%, total nitrogen - by 6.9% with a decrease in ammonia, as well as an increase in the number of red blood cells in the blood by 3.9%, hemoglobin - by 5.4%, glucose - by 5.1%, with an increase in the activity of ALT and AST enzymes by 5.6 and 6.2%. Feeding whole milk substitute and feed to young animals with a duration of the dairy period of 90 days contributes to an increase in average daily gains in the post-dairy period by 5.4%, while reducing the cost of growth by 4.4%, which allowed for an additional profit of 6.64 rubles (2.6 US dollars) per head during the research period.

Indicators of volatile fatty acids for differential diagnostics of nfected of pancreatic necrosis complicated by retroperitoneal phlegmon.

The aim of the study was to assess the informative value of volatile fatty acid parameters for the differential diagnosis of infected pancreatic necrosis (IPN), complicated by retroperitoneal cellulitis. The work was based on the results of examination and treatment of 44 patients with infected pancreatic necrosis. The analysis of concentrations of volatile fatty acids: acetic, propionic, butyric and isovalerianic was carried out on a Kristallux-4000 automated gas chromatograph with an HP-FFAP capillary column and a flame ionization detector. The indicators of acetic acid and the amount of volatile fatty acids were statistically significantly higher in patients with infected pancreatic necrosis with total retroperitoneal phlegmons in comparison with the indicators of volatile fatty acids in patients with infected pancreatic necrosis with paracolic phlegmons and in comparison with indicators of volatile fatty acids in patients with infected pancreatic necrosis phlegmons. The indicators of acetic acid and the amount of VFA can be used as additional criteria for the differential diagnosis of IPN complicated by phlegmons of the retroperitoneal tissue.

Effect of pH on the Economic Potential of Dark Fermentation Products from Used Disposable Nappies and Expired Food Products

Used disposable nappies constitute a waste stream that has no established treatment method. The purpose of this study was the assessment of the dark fermentation of used disposable nappies and expired food products under different pH values. The biodegradable part of the used disposable nappies was recovered and co-fermented with expired food products originating from supermarkets. The recoverable economic potential of the process was examined for different volatile fatty acids exploitation schemes and process pH values. The process pH strongly affected the products, with optimum hydrogen production at pH 6 (4.05 NLH2/Lreactor), while the amount of produced volatile fatty acids was maximized at pH 7 (13.44 g/L). Hydrogen production was observed at pH as low as pH 4.5 (2.66 NLH2/Lreactor). The recoverable economic potential was maximized at two different pH values, with the first being pH 4.5 with minimum NaOH addition requirements (181, 138, and 296 EUR/ton VS of substrate for valorization of volatile fatty acids through microbial fuel cell, biodiesel production, and anaerobic digestion, respectively) and the second being pH 6, where the hydrogen production was maximized with the simultaneous production of high amounts of volatile fatty acids (191, 142, and 339 EUR/ton VS of substrate respectively).

Influence of Cane Molasses Inclusion to Dairy Cow Diets during the Transition Period on Rumen Epithelial Development.

Simple SummaryThe rumen epithelium of dairy cattle undergoes a transformation in response to dietary and physiological changes. Rumen papillae development and adaptation from a typical dry cow diet to a lactating diet can require a substantial amount of time, subsequently limiting the amount of volatile fatty acids (VFA) absorbed from the rumen during early lactation. Infusions of butyrate into the rumen of sheep stimulates cellular proliferation of rumen epithelial tissue, which may prove beneficial for ruminal papillae development in dairy cows during the dry period. However, no studies have investigated mechanisms associated with rumen epithelial adaptation in periparturient dairy cattle. Our hypothesis was that supplementation with cane molasses containing 34% sucrose during the prepartum period would stimulate ruminal butyrate production and ultimately promote ruminal papillae development and absorption rate, thus increasing dry matter intake (DMI) and milk production during the postpartum period. Results from these experiments indicate that diets containing cane molasses during a 60 day dry period can positively influence transition cow performance. The objective of this study was to evaluate the addition of cane molasses during a 60 day dry period on performance and metabolism of Holstein cows during prepartum and postpartum periods. For experiment 1, 26 primiparous and 28 multiparous cows were used. Upon freshening, all cows were offered a common lactation diet. For experiment 2, six multiparous cows fitted with rumen cannulas were used to measure performance and metabolism, following the same protocol as experiment 1. Ruminal propionate increased by 10% during both prepartum and postpartum periods; however, papillae area was greater for cows not fed molasses, and volatile fatty acids (VFA) absorption from the rumen was not increased, resulting in similar glucagon-like-peptide-2 receptor (GLP-2R) density. The improved dry matter intake, when molasses was added into prepartum diets, translated into increased milk yield and energy-corrected milk (ECM) in Experiment 1 only for multiparous cows. For experiment 2, the improvement on milk performance was also observed, where cows fed molasses had 18.5% greater ECM production. Feeding molasses during a 60 day dry period positively influenced transition cow performance, and it was not accompanied by changes in rumen morphometrics; however, this indicates enhanced adaptation by the rumen epithelium based on similar capabilities for VFA absorption.

The cross-over fermentation concept and its application in a novel food product: The dairy miso case study

Cross-over fermentations are processes in which a microorganism from one traditional fermentation process is introduced onto a new substrate and/or to a new partner. Here we show that Aspergillus oryzae normally used for the production of miso, a fermented soybean paste from Asia, can be applied to a traditional European fermented dairy product quark cheese, produced by fermenting milk with Lactococcus lactis. This cross-over fermentation resulted in a product with intense aroma properties, mainly due to high amounts of volatile fatty acids, ethyl esters, higher alcohols and ketones. Active metabolism of A. oryzae was required for alcohol production, whereas fat degradation occurred mainly due to enzymatic activities. Traditionally used practices in miso production, like mixing, addition of various amounts of salt and variations in fat content of the substrate altered metabolic and enzymatic properties of A. oryzae resulting in differences in final product characteristics. Aroma intensity of the product was shown by comparing volatile organic compounds with blue and white mould cheese. This study showed the potential of cross-over fermentation for novel food products. The enormous diversity of microorganisms used in traditional fermentation processes and the vast number of alternative substrates offer numerous opportunities for further novel fermented product development.

Effect of probiotics on rumen microorganisms

The article presents the results of a study on the use of probiotics based on strains of spore-forming microorganisms Bacillus lisheniformis and Bacillus subtilis for young cattle. The use of probiotics in dairy farming increases the body's resistance, restores the intestinal microbiocenosis and reduces the risk of infectious diseases of animals, prevention and treatment of dysbacteriosis. The importance of the microbial population in feed transformation and rumen fermentation processes to increase animal productivity and reduce the occurrence of rumen acidosis. The introduction of probiotics improves the health of the animal, competing for the use of nutrients by pathogenic microbes, having a positive effect on the intestinal microflora. In addition, their antipathogenic activity can reduce stress in animals. The aim of the study was to determine the effect of probiotic strains of microorganisms on the microflora of the gastrointestinal tract in calves. The research was carried out in the conditions of the farm of "Khlibodar", Sumy region, which keeps cattle of different technological groups. The use of probiotic strains of spore-forming microorganisms Bacillus lisheniformis and Bacillus subtilis affected the results of scar fermentation, such as the amount of volatile fatty acids, ammonia concentration of the scar and the pH of the scar. The mechanism of action of the bacterium B. subtilis is associated with the ability to produce antibiotic-like substances and enzymes and strengthen the body's defenses against common and specific pathogens, to stimulate the normal growth of intestinal microflora. Produced by B. subtilis substances also actively inhibit the growth and development of harmful bacteria, viruses and fungi, without causing them to become addicted. Immunomodulatory action is associated with the activation of macrophages, strengthening the barrier function of the intestine, activation of T and B lymphocytes. Destroying harmful microorganisms, free up space for the settlement of lacto-and bifidobacteria, which are typical representatives of the normal microflora.

Psychrophilic properties of sulfate‐reducing bacteria in Arctic marine sediments

AbstractMicroorganisms in the seabed of most of the global oceans live at temperatures close to zero degrees, and in the polar regions even below. Respiration rates of endogenous sulfate‐reducing microorganisms in the polar seabed, however, are highest in the range of 18–30°C and much reduced at colder temperature. In the past, this was seen as indicative of poor adaptation to their cold habitat. We challenge this interpretation, and tested which temperature range allowed sulfate reducers to grow, by adding moderate amounts of volatile fatty acids to high‐arctic sediment. Initially, sulfate reduction was highest at 27°C in both Svalbard and NE Greenland. But sulfate reduction was not sustainable at this temperature and decreased rapidly over time. Below 26°C, however, sulfate reduction rates increased exponentially over time, indicating growth of sulfate‐reducing microorganisms. We used the increase in the sulfate reduction rates over 4 d to calculate potential growth rates of the endogenous sulfate reducers as function of temperature. From growth rates and respiration rates, we could further calculate the growth yield, also as function of temperature. Highest growth rates were observed at 18°C and growth yields peaked at even lower temperatures between 0°C and 10°C. The maximum growth yield at low temperature revealed a strong psychrophilic adaptation of the sulfate reducers in these Arctic sediments. The fact that growth yield was maximized at in situ temperature but maximum potential growth rate was not, is an indication that yield is the more important parameter for microbial competition in marine sediments.