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Bacillus velezensis R22 was isolated from a rice rhizosphere in Bulgaria. Its genome (assembled into 14 scaffolds) has a size of 4.08 Mbp and a G + C content of 46.35%. Nine full biosynthetic clusters for antimicrobials were predicted, among them two new gene clusters probably encoding polyketides named macrolactin R22 and velezensin., Competing Interests: The authors declare no conflict of interest.

The properties of Bacillus thuringiensis strains as a biopesticide with potent action against moths, beetles, and mosquitoes have been known for decades, with individual subspecies showing specific activity against a particular pest. The aim of the present work is to characterize strains that can be used for broad-spectrum pest control in agriculture. Twenty strains of B. thuringiensis were isolated from Bulgarian soil habitats. The strains were screened for genes encoding 12 different crystal (Cry) endotoxins by PCR with specific primer pairs. Seven of the isolates contained cry genes in their genomes. B. thuringiensis strains PL1, PL3, and PL20 contained at least three different cry genes, while B. thuringiensis serovar galleriae BTG contained at least four. Moreover, scanning electron microscopy (SEM) investigation revealed the production of bipyramidal (PL1, PL3, PL20), polygonal (PL1), cubic (BTG), and spherical crystals (BTG and PL20). Potentially containing the most cry genes, the BTG genome was sequenced and annotated. It comprises 6,275,416 base pairs, does not contain plasmids, has a GC content of 35.05%, and contained 7 genes encoding crystal toxins: cry1Ab35 , cry1Db , cry1Fb , cry1Ib , cry2Ab , cry8Ea1 , and cry9Ba . This unique combination would possibly enable the simultaneous pesticidal action against pest species from orders Lepidoptera, Coleoptera, Diptera, and Hemiptera, as well as class Gastropoda. Whole-genome sequencing provided accurate information about the presence, localization, and classification of Cry toxins in B. thuringiensis BTG, revealing the great potential of the strain for the development of new broad-spectrum bio-insecticides.

The degradation kinetics of different phenolic substrates utilised by Trichosporon cutaneum R57 was studied. The following compounds were used as substrates: phenol , resorcinol, hydroquinone, 3-nitrophenol, 2,6-dinitrophenol, 3-chloro phenol and p -cresol. The specific degradation rates ( Q s ) were described by a Haldane kinetic model. The unknown model parameters were estimated using the mathematical optimisation procedure for direct search. The results obtained demonstrated that Q s varied greatly in the experiments carried out. The level of biodegradability depended on the different structure and toxicity of compounds used as carbon substrates. The highest Q s values were observed for less toxic hydroxylated phenols (0.77-0.85 h -1 ), while the most toxic chlorinated phenols were characterised with the lowest Q s values (0.224 h -1 ). The results obtained with different concentrations of resorcinol (from 0.2 to 0.8 g L -1 ) and 2,6-dinitrophenol (from 0.2 to 0.7 g L -1 ) demonstrated a growing inhibitory effect directly correlating with the extended time necessary for complete degradation of both compounds.