Comparison of Carbonic Anhydrases for CO2 Sequestration

Strategies for depleting carbon dioxide (CO2) from flue gases are urgently needed and carbonic anhydrases (CAs) can contribute to solving this problem. They catalyze the hydration of CO2 in aqueous solutions and therefore capture the CO2. However, the harsh conditions due to varying process temperatures are limiting factors for the application of enzymes. The current study aims to examine four recombinantly produced CAs from different organisms, namely CAs from Acetobacterium woodii (AwCA or CynT), Persephonella marina (PmCA), Methanobacterium thermoautotrophicum (MtaCA or Cab) and Sulphurihydrogenibium yellowstonense (SspCA). The highest expression yields and activities were found for AwCA (1814 WAU mg−1 AwCA) and PmCA (1748 WAU mg−1 PmCA). AwCA was highly stable in a mesophilic temperature range, whereas PmCA proved to be exceptionally thermostable. Our results indicate the potential to utilize CAs from anaerobic microorganisms to develop CO2 sequestration applications.

Evaluation of microbiological risks in cream as a raw material for buttermaking

The article presents the research results of studying the influence of various groups of microorganisms — coliform bacteria, lactic acid microorganisms, yeast, and spore bacteria — on the quality and storage capacity of cream used as a raw material for buttermaking. The objects of study were the following: cream as a raw material before and after pasteurization, as well as pasteurized cream seeded with testing cultures of various types of spoilage microorganisms. The samples were stored at temperature conditions of 30 ± 1 °C, 10 ± 1 °C, and 4 ± 2 °C. To evaluate the quality and storage capacity of cream used as a raw material, its microbiological and physicochemical indicators were determined by standardized methods: bacterial number, titratable acidity, indicators of oxidative spoilage of the fat phase. Organoleptic characteristics were evaluated in terms of taste, consistency and appearance. Research results have shown that the greatest microbiological risks during storage of cream used as a raw material are associated with lactococci, coliform bacteria and yeast. Microbiological risks caused by seeding of cream with thermophilic streptococcus, spore bacteria of the genus Bacillus and spore anaerobic microorganisms of the genus Clostridium are less significant, which is associated with the lack of development and metabolism of these groups of microorganisms at storage temperatures of 10 ± 1 °C and 4 ± 2 °C. At the same time, the reason for the rejection of cream contaminated with these testing cultures, at a storage temperature of 4 ± 2 °C, is primarily a decrease in organoleptic indicators, and at a temperature of 10 ± 1 °C — an excess in bacterial number.

Studying sanitary and hygienic conditions of bream and water in its habitat

The article highlights the data on microbiological monitoring of fish raw materials and water of the Volga-Caspian fishing channel in 2020-2021. The most indicative organisms for assessing the quality of the aquatic environment are benthos-eating fish. Bream Abramis brama (Linnaeus, 1758) is one of the valuable objects of fishing in the Astrakhan region. As a commercial object of river coastal fishing, bream has a higher bacterial contamination than fish caught in the sea. In this regard, studying the conditions for bacteriocenosis of fish raw materials, as well as the factors that determine the pathogenicity of its microflora and sanitary and epizootic monitoring by the microbiological tests remain the most relevant research of aquatic organisms. Quantitative and qualitative indicators of the bream microflora were estimated, according to the analysis of 180 species. The indicators of the water microflora were analyzed using the results of studies of 90 samples. The species identification of the isolated microflora was carried out according to the Bergey identification keys. In the samples of bream muscles there was determined the total number of facultative anaerobic microorganisms and aerobic mesophylls, presence of coliform microorganisms, as well as a causative agent of Staphylococcus aureus, pathogenic bacteria Salmonella and Listeria, and parahemolytic vibrios Vibrio. The study results were processed, according to the methods of biological statistics in the Microsoft Excel 2010 software. The results are presented as mean values and standard errors (M ± m). The general microbiological analysis of the fish muscle tissue confirmed the satisfactory sanitary state of bream Abramis brama (L., 1758) caught in the fishing area of the Volga-Caspian Canal during the study period. Pathogenic microflora in the form of E. coli bacteria, bacteria Salmonella, L. monocytogenes and St. aureus were not found

Species Composition and Susceptibility to Antibiotics of Microorganisms Isolated from Tooth Sockets of Extracted Teeth in Cases of Alveolar Osteitis

Alveolar osteitis (AO) is one of the most common infectious complications after dental extractions. The data on the species composition of AO pathogens and their susceptibility to antimicrobial drugs can be the basis for their empirical use in case of inflammatory process aggravation. Objective. To determine the species composition and susceptibility to the antimicrobial agents of microorganisms, which were detected in patients with AO, who sought medical help in the oral surgery department of the dental medical center of Bogomolets National Medical University. Methods. Throughout 2018–2021, microbiological examination of tooth sockets from 30 patients with AO and 20 patients without AO was performed. The studied biological material was plated on appropriate nutrient media for isolation of aerobic, facultative and obligate-anaerobic microorganisms. Anaerobic conditions were achieved in GENbox 7.0 L and GENbox 2.5 L aerostats using GENbox anaerobic packages (“Biomerieux”, France). The genus and species identity of the bacteria were determined according to Bergey. Antibiotic susceptibility of the isolated strains was determined by disk diffusion method. Results. It was found that most commonly microorganisms from tooth sockets in case of AO are: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Escherichia coli, Bacteroides spp., Clostridium spp., and Candida species, as well as their mixed cultures of 3–5 species of microorganisms. These aerobic and facultative anaerobic bacteria were susceptible to amoxicillin, ceftriaxone and ciprofloxacin in 92.6–100% of cases. The growth of anaerobic bacteria in 100% of cases was inhibited by colistin and meropenem. Conclusions. AO developing is caused by pathological colonization of socket of the extracted tooth by representatives of endogenous microbiota, namely Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Escherichia coli, which are present mainly in the mixed cultures with Candida albicans. For empirical antibiotic therapy of complicated forms of AO, amoxicillin or ceftriaxone or ciprofloxacin in complex with colistin or meropenem should be used, since these drugs suppress the growth of 92.6–100% of strains of aerobic, facultative and obligate anaerobic microorganisms, which are potential pathogens of the purulent forms of AO.

Quality control of butter

The most common problem among ready-made foods is the adulteration of butter, which is replaced by margarine or vegetable spreads. Milk and other dairy products made from raw milk are not left out. The production and sale of low-quality, counterfeit products poses a direct threat to human health and affects the competitive environment among producers. As a result of research, it should be noted that the raw milk market is not fully saturated, so improving the quality of cream production and processing of milk products, namely butter, competition for suppliers, microbiological improvements, as well as improvements to plants and systems – remains relevant. During the analysis, some physicochemical parameters of butter were studied, namely: acidity of the fat phase, mass fraction of moisture and fat. The acidity index was within the norm, although it differed in all samples: the lowest was found in sample № 1 (1.1 °K), and the highest was in sample № 2 (1.6 °K). As for such an indicator as the content of table salt and the content of fat and pH of plasma, the oils Sweet cream “Selyanske”, 72,6 % TM “Svoya Liniya”, Sweet cream, 73.0 % LLC “Eney”, “Poltavske”, 62.5 % LLC “Techmolprom” do not meet the requirements of DSTU 4399:2005. The mass fraction of fat in butter brands PJSC “Dubnomoloko” and “Pryvat-Fud” – was lower than indicated on the package, by 1.4 % and 2.6 %, respectively, and brands “Svoya Liniya”, LLC “Eney” and Techmolprom LLC on the contrary – by 18.0 %, 18.4 % and 12.5 % more. According to the results of microbiological studies, it was found that the number of mesophilic aerobic and facultatively anaerobic microorganisms, yeasts, fungi and bacteria of the Escherichia coli group in the studied samples of butter of all brands does not exceed the permissible norms. This fact testifies to the relative “purity” of the raw material from which the butter was made, as well as to the observance of veterinary and sanitary and hygienic norms during the production and storage of butter. Summing up the research, it should be noted that, despite the identified physical and chemical shortcomings of all samples of butter, preference should be given to sour cream butter “Selyanske”, 73.0 % of PJSC “Dubnomoloko” and “Selyanske” sweet cream, 73.0 % “Privat- Fud”, as none of them exceeded such indicators as fat content and plasma pH of oil, which may indicate the absence of impurities in vegetable fats in this product.

Imbalanced Dermic Microbiome Aggravates Inflammation in Toenail Paronychia

The commensal microbiome influences skin immunity, but its function in toenail health remains unclear. Paronychia is one of the most common inflammatory toenail diseases, but antibiotic treatment is seldom effective in clinical cases. In this study, we performed 16S rRNA sequencing to investigate the characteristics of microbes associated with paronychia in order to identify the key microorganisms involved in inflammation. Seventy dermic samples were collected from patients with paronychia and the differences in dermic microbiota were analyzed in patients with different inflammation severities. Distinct clustering of dermal microbiota was observed in the dermis with different inflammation severities. A higher relative abundance of anaerobic microorganisms such as Parvimona, Prevotella, and Peptoniphilus was observed in severe paronychia, whereas Lactobacillus disappeared with disease progression. Co-occurring network analysis suggested that the disturbance of the dermic microbiome and attenuation of antagonism by Lactobacillus against anaerobic pathogens may aggravate inflammation in paronychia. Functional analysis showed that dermic microbiome disturbance may worsen microbial metabolism and tissue repair in the skin. In conclusion, we revealed that an increased abundance of anaerobic microorganisms and loss of Lactobacillus in the dermis may promote paronychia progression and microbiological imbalance may aggravate inflammation in patients with paronychia.

Pre-treatment Effect on Physical and Microbial Parameters of Smoked Baltic Sprats

Smoked sprats are delicious and nutritionally valuable product. Besides protein, it contains high amount of unsaturated fatty acids and fat soluble vitamins. Nowadays, human interest for fish product consumption is increasing. It leads to the demand for increased shelf life of the smoked sprats. One way to prolong the shelf life is to use some pre-treatment prior to smoking. The aim of study was to analyse the effect of pre-treatment on smoked Baltic sprat quality and microbiological parameters. Various compositions of brine using salts (NaCl, CaCl2) and acetic acid in different proportions were used for fresh sprat pre-treatment. Pre-treatment had the influence on physical parameters; pre-treated samples had higher salt and lower moisture content, and lower pH, which allowed prolonging the shelf life of smoked sprats. The highest pH was in the control sample 6.6, and it allowed growth of yeasts, moulds, Pseudomonas spp., and mesophilic and facultative anaerobic microorganisms. The results demonstrated that after two-week storage of the smoked sprats the growth of moulds (1×102 CFU g−1) was observed only for smoked sprats without pre-treatment (control sample), indicating the positive effect of pre-treatment. Salmonella spp., Clostridium perfingens, Listeria monocytogenes, and Escherichia coli were not detected in any of the analysed samples. After pre-treatment in brine, containing combination of NaCl and CaCl2, smoked fish had darker colour compared to control sample or sample with sodium chloride only. Any of applied pre-treatments, except brine containing NaCl, made firmer texture of the smoked fish.

Examination of Extracellular Polymer (EPS) Extraction Methods for Anaerobic Membrane Bioreactor (AnMBR) Biomass

Membrane bioreactor fouling is a complex process, which is typically driven by extracellular polymeric substances (EPS), a complex mixture of polysaccharides, proteins, lipids, humic substances, and other intercellular polymers. While much is known about fouling in aerobic membrane reactors, far less is known about fouling in anaerobic membrane bioreactors (AnMBR). Much of this knowledge, including EPS extraction methods, has been extrapolated from aerobic processes and is commonly assumed to be comparable. Therefore, several extraction methods commonly used for aerobic EPS quantification, including ultrasonication, ethylenediaminetetraacetic acid (EDTA), and formaldehyde plus sodium hydroxide (CH2O+NaOH), were evaluated to determine the most suitable extraction method for EPS of anaerobic microorganisms in an AnMBR. To maximize EPS yields, each extraction was performed four times. Experimental results showed that the EDTA method was best for EPS quantification, based on chemical oxygen demand (COD), dissolved organic carbon (DOC), and protein yields: 1.43 mg COD/mg volatile suspended solids (VSS), 0.14 mg DOC/mg VSS, and 0.11 mg proteins/mg VSS. In comparison, the CH2O+NaOH method maximized the extraction of carbohydrates (0.12 mg carbohydrates/mg VSS). However, multiple extraction cycles with EDTA and ultrasonication exhibited lower extracellular adenosine triphosphate (ATP) concentrations compared to CH2O+NaOH extractions, indicating lower levels of released intracellular substances. Successive EPS extractions over four cycles are better able to quantify EPS from anaerobic microorganisms, since a single extraction may not accurately reflect the true levels of EPS contents in AnMBRs, and possibly in other anaerobic processes.

Devising the formulation and technology for baking buns from flour of composite mixtures and sugar beet

The composition of legumes and sugar beet contains a large number of useful mineral and vitamin substances. The use of composite flour from leguminous crops for the preparation of bakery products helps increase food and biochemical properties. The main objects of this research are chickpea flour, bean flour, dry sugar beet powder, and wheat flour of the first grade. The main problem is an insufficient amount of minerals and vitamins, so the purpose of this work is to enrich bakery products and replace sugar in the recipe with sugar beet powder. The results showed that composite flour and sugar beet increased calcium content by 13.54 mg/100 g, iron ‒ by 0.57 mg/100 g, potassium ‒ by 141.03 mg/100 g, phosphorus ‒ by 38.89 mg/100 g, vitamin A ‒ by 0.002 mg/100 g, vitamin B2 ‒ by 0.016 mg/100 g, vitamin E ‒ by 0.32 mg/100 g, and vitamin PP ‒ by 0.405 mg/100 g. Microbiological indicators meet the established norms and requirements; the amount of mesophilic aerobic and facultative-anaerobic microorganisms, yeast, and mold in the test bun was the least compared to the control sample. As a result, it was proved that the use of composite flour of leguminous crops contributes to an increase in the nutritional and biological values of bakery products, and the application of dried sugar beet powder makes it possible to completely exclude sugar from the formulation of the resulting product. Employing this technology and formulations for obtaining bakery products makes it possible to expand the range of bakery products, reduce the duration of the manufacturing process, improve the quality of finished products, increase labor productivity. That also contributes to the improvement of the socio-economic indicators of bakery and confectionery enterprises