Exploring Extremophiles from Bulgaria: Biodiversity, Biopolymer Synthesis, Functional Properties, Applications.

Bulgaria stands out as a country rich in diverse extreme environments, boasting a remarkable abundance of mineral hot waters, which positions it as the second-largest source of such natural resources in Europe. Notably, several thermal and coastal solar salterns within its territory serve as thriving habitats for thermophilic and halophilic microorganisms, which offer promising bioactive compounds, including exopolysaccharides (EPSs). Multiple thermophilic EPS producers were isolated, along with a selection from several saltern environments, revealing an impressive taxonomic and bacterial diversity.

Degradation of Poly(ε-caprolactone) by a Thermophilic Community and Strain 7 Isolated from Bulgarian Hot Spring.

The continual plastic accumulation in the environment and the hazardous consequences determine the interest in thermophiles as possible effective plastic degraders, due to their unique metabolic mechanisms and change of plastic properties at elevated temperatures. PCL is one of major biodegradable plastics with promising application to replace existing non-biodegradable polymers. Metagenomic analysis of the phylogenetic diversity in plastic contaminated area of Marikostinovo hot spring, Bulgaria revealed a higher number taxonomic groups (11) in the sample enriched without plastic (Marikostinovo community, control sample, MKC-C) than in that enriched in the presence of poly-ε-caprolactone (PCL) (MKC-P), (7).

Improved Exopolymer Production by Cultures for Its Potential Cosmeceutical Applications.

Several exopolymers with different chemical composition and correspondingly variety in their physico-chemical properties from halophilic microorganisms have still been described, however, with a low production yield. 28 isolated from Pomorie saltern synthesized an unusual exopolymer (EP) containing 72% γ-polyglutamic acid (PGA), an essential cosmeceutical additive. Current work suggests a novel approach for effective EP synthesis by 28 using continuous cultures.

High bioreactor production and emulsifying activity of an unusual exopolymer by 28.

Unusual composition of an exopolymer (EP) from an obligate halophilic bacterium 28 has triggered an interest in development of an effective bioreactor process for its production. Its synthesis was investigated in 2-L bioreactor at agitation speeds at interval 600-1000 rpm, at a constant air flow rate of 0.5 vvm; aeration rates of 0.

Extracellular polymer substance synthesized by a halophilic bacterium Chromohalobacter canadensis 28.

Halophilic microorganisms are producers of a lot of new compounds whose properties suggest promising perspectives for their biotechnological exploration. Moderate halophilic bacterium Chromohalobacter canadensis 28 was isolated from Pomorie salterns as an extracellular polymer substance (EP) producer. The best carbon source for extracellular polymer production was found to be lactose, a sugar received as a by-product from the dairy industry.

Unusually High Archaeal Diversity in a Crystallizer Pond, Pomorie Salterns, Bulgaria, Revealed by Phylogenetic Analysis.

Recent studies on archaeal diversity in few salterns have revealed heterogeneity between sites and unique structures of separate places that hinder drawing of generalized conclusions. Investigations on the archaeal community composition in P18, the biggest crystallizer pond in Pomorie salterns (PS) (34% salinity), demonstrated unusually high number of presented taxa in hypersaline environment. Archaeal clones were grouped in 26 different operational taxonomic units (OTUs) assigned to 15 different genera from two orders, Halobacteriales and Haloferacales.

Archaeal and bacterial diversity in two hot springs from geothermal regions in Bulgaria as demostrated by 16S rRNA and GH-57 genes.

Archaeal and bacterial diversity in two Bulgarian hot springs, geographically separated with different tectonic origin and different temperature of water was investigated exploring two genes, 16S rRNA and GH-57. Archaeal diversity was significantly higher in the hotter spring Levunovo (LV) (82°C); on the contrary, bacterial diversity was higher in the spring Vetren Dol (VD) (68°C). The analyzed clones from LV library were referred to twenty eight different sequence types belonging to five archaeal groups from Crenarchaeota and Euryarchaeota.

Genomic analysis of Brevibacillus thermoruber 423 reveals its biotechnological and industrial potential.

Brevibacillus thermoruber 423 is a Gram-positive, motile, red-pigmented, spore-forming, aerobic, and thermophilic bacterium that is known to produce high levels of exopolysaccharide (EPS) with many potential uses in food, feed, cosmetics, and pharmaceutical and chemical industries. This bacterium not only is among the limited number of reported thermophilic EPS producers but also exceeds other thermophilic producers in light of the high level of polymer synthesis. By a systems-based approach, whole-genome analysis of this bacterium was performed to gain more insight about the biological mechanisms and whole-genome organization of thermophilic EPS producers and hence to develop rational strategies for the genetic and metabolic optimization of EPS production.

Production and properties of two novel exopolysaccharides synthesized by a thermophilic bacterium Aeribacillus pallidus 418.

Synthesis of innovative exocellular polysaccharides (EPSs) was reported for few thermophilic microorganisms as one of the mechanisms for surviving at high temperature. Thermophilic aerobic spore-forming bacteria able to produce exopolysaccharides were isolated from hydrothermal springs in Bulgaria. They were referred to four species, such as Aeribacillus pallidus, Geobacillus toebii, Brevibacillus thermoruber, and Anoxybacillus kestanbolensis.