Different non-digestible di- and oligosaccharides act as prebiotics. Common prebiotics in use include inulin and other fructo-oligosaccharides (FOS), galacto-oligosaccharides (GalOS), xylo-oligosaccharides, gluco-oligosaccharides (GOS), lactulose, etc. The principal concept is that these sugars have a selective effect on the microbiota that results in an improvement in the health of the host, leading to an increase in health-promoting organisms such as different kinds of Lactic acid bacteria (LAB). With our latest results we describe the effects of utilization of different prebiotics upon specific LAB-strains, their antimicrobial activity and the changes in the metabolites.

The accumulation of microplastics in the world oceans is one of the main global problems of the modern world. The Black Sea is the main source of seafood for people from several countries, including Bulgaria. The pollution of the Black sea is a result of various factors, especially anthropogenic. The aim of this study was to determine the presence and accumulation of microplastics in the Black Sea mussel Mytilus galloprovincialis L., 1819, harvested from different locations along the northern Bulgarian Black Sea coast. Within each microplastic morphological group, three size classes were recognized: 100-200 μm, 25-100 μm, and ≤ 25 μm. Microplastics were found in the soft tissues of all studied specimens but in a different ratio of pellets, fibers and fragments. Generally, the pellets were the most often registered particles, followed by irregularly-shaped fragments, whereas fibers were less numerous. The dominant part of the isolated plastics are made of polyethylene (PE), and polyethylene terephthalate (PET). Our results pointed out serious pollution with plastic particles in the Bulgarian Black Sea aquatory, which in the future may seriously affect the health of the mussel population and also human health.

One of the main problems of the world's oceans, reported by many scientific studies, is the microplastic pollution. Within the Black Sea, one of the main sources of pollution is the same, which is caused by the diverse anthropogenic activities. The present study demonstrated detailed microplastics contamination of in five fish species important for the commercial fishing (Garfish, Мullet, Knout goby, Pontic shad and Mediterranean horse mackerel). They were collected from the Sozopol area on the Bulgarian Black Sea coast. Within each microplastic morphological group, three size classes were recognised: 100–200 µm, 25–100 µm and ≤ 25 µm. Microplastics were found in all studied tissues of the fish, but in varying proportions of pellets, fibres and fragments. Pellets were most frequently isolated, followed by irregularly-shaped fragments and fibres were the least numerous. The bulk of insulated plastics are made of polyethylene (PE) and polyethylene terephthalate (PET). Our results pointed out serious pollution with plastic particles in the Bulgarian Black Sea aquatory, which, in the future, may seriously affect the health of the fish population and also human health.

Bacterial EPSs (exopolysaccharides) are believed to play an important role in the environment by promoting survival strategies such as bacterial attachment to surfaces and nutrient trapping, which facilitate processes of biofilm formation and development. These microbial biofilms have been implicated in corrosion of metals, bacterial attachment to prosthetic devices, fouling of heat exchange surfaces, toxicant immobilization, and fouling of ship hulls. In this paper, data on EPS production and the effect of EPS on corrosion of steel produced by Lactobacillus sp. are presented and discussed. Lactobacillus delbrueckii K27, Lactobacillus delbrueckii B8, Lactobacillus delbrueckii KO43, Lactobacillus delbrueckii K3, Lactobacillus delbrueckii K15 and Lactobacillus delbrueckii K17 was obtained from Collection of Department of General and Applied Microbiology, Sofia University. It was tested for its ability to produce exopolysaccharides when cultivated in a media containing 10% sucrose, 10% lacose and 10% maltose. The study of the corrosive stability of steel samples was conducted on the gravimetrique method. The rate of corrosion, the degree of protection, and coefficient of protection have been calculated. The structure of layer over steel plates was analysed by SEM (scanning electron microscopy) JSM 5510. It could be underlined that 10% sucrose, 10% lactose and 10% maltose in the media stimulated the process of protection of corrosion.

The current study aims for the isolation and physicochemical characterization of inulin from defatted dandelion roots using green extraction techniques, including microwave extraction (MAE) and ultrasound-assisted extraction (UAE). The structure and degree of polymerization of inulin were elucidated by chromatographic techniques, as well as by FTIR and NMR spectroscopies. The color characteristics, water- and oil-holding capacity, solubility, swelling properties, wettability, angle of repose, flowability, and cohesiveness of dandelion inulin were evaluated. Moreover, the antioxidant and antibacterial potential of dandelion inulin were revealed. The results were compared with the conventional extraction and inulin from chicory. Dandelion inulin was evaluated as a powder substance with a degree of polymerization (DP) of 17–24. The highest yield (20%) was obtained by classical extraction; however, UAE and MAE demonstrated the highest purity. FT-IR and NMR spectra revealed that dandelion inulin is glucofructan with a molecular weight of 2.7–3.2 kDa that consists mainly of fructosyl units β-(2→1) linked to one α-D-glucose unit UAE was evaluated as the most perspective technique for the simultaneous extraction of inulin from dandelion roots, with the highest average DP 24 and high purity (82%), molecular mass, total fructose content, swelling index, and oil-holding capacity. Dandelion inulin exhibited intermediate cohesiveness, fair flowability, and moderate antimicrobial activity against Listeria monocytogenes 863 and Bacillus subtilis 6633. The physicochemical and functional properties of dandelion inulin reveal its future potential as an additive in food, cosmetic, and pharmaceutics formulations as a texture modifier, a fat replacer, and a drug carrier.