This paper tackles bacteria of the genus Bacillus as both biodamaging/biodegrading and biocontrolling agents. The article addresses the said bacteria’s ability to form biofilms and corrosive, antimicrobial and antibiofilm proactive compounds, primarily, siderophores. Their role depends on the species, microorganism strain, production of antimicrobial substances, biofilm formation, and the type of damaged material. The bacteria under analysis have demonstrated the ability to cause as well as inhibit biodamage. The involvement of bacteria of the genus Bacillus in microbiologically influenced corrosion processes is determined by the production of corrosive metabolites and the impact of certain bioelectrochemical mechanisms. Lipopeptides generated by Bacillus subtilis (surfactin, iturin and fengycin) are capable of modifying surfaces’ hydrophobic properties and impacting the microbes’ adhesion to surfaces. Produced by Bacillus velezensis, the siderophore bacillibactin at a high concentration is capable of inhibiting the formation of bacterial biofilms, thus slowing down the degradation of materials. Further study of siderophores as green inhibitors of microbiologically influenced corrosion may be promising as the said compounds possess antibiofilm-forming properties and high-intensity inhibitory capabilities.

Microbe-based decontamination of phenol-polluted environments has significant advantages over physical and chemical approaches by being relatively cheaper and ensuring complete phenol degradation. There is a need to search for commercially prospective bacterial strains that are resistant to phenol and other co-pollutants, e.g. oil hydrocarbons, in contaminated environments, and able to carry out efficient phenol biodegradation at a variable range of concentrations. This research characterizes the phenol-biodegrading ability of a new actinobacteria strain isolated from a lubricant-contaminated soil environment. Phenotypic and phylogenetic analyses showed that the novel strain UCM Ac-603 belonged to the speciesRhodococcus aetherivorans, and phenol degrading ability was quantitatively characterized for the first time.R.aetherivoransUCM Ac-603 tolerated and assimilated phenol (100% of supplied concentration) and various hydrocarbons (56.2–94.4%) as sole carbon sources. Additional nutrient supplementation was not required for degradation and this organism could grow at a phenol concentration of 500 mg L⁻¹without inhibition. Complete phenol assimilation occurred after 4 days at an initial concentration of 1750 mg L⁻¹for freely-suspended cells and at 2000 mg L⁻¹for vermiculite-immobilized cells: 99.9% assimilation of phenol was possible from a total concentration of 3000 mg L⁻¹supplied at daily fractional phenol additions of 750 mg L⁻¹over 4 days. In terms of phenol degradation rates,R.aetherivoransUCM Ac-602 showed efficient phenol degradation over a wide range of initial concentrations with the rates (e.g. 35.7 mg L⁻¹ h⁻¹at 500 mg L⁻¹phenol, and 18.2 mg L⁻¹ h⁻¹at 1750 mg L⁻¹phenol) significantly exceeding (1.2–5 times) reported data for almost all other phenol-assimilating bacteria. Such efficient phenol degradation ability compared to currently known strains and other beneficial characteristics ofR.aetherivoransUCM Ac-602 suggest it is a promising candidate for bioremediation of phenol-contaminated environments.

Europe’s forests, particularly in Ukraine, are highly vulnerable to climate change. The maintenance and improvement of forest health are high-priority issues, and various stakeholders have shown an interest in understanding and utilizing ecological interactions between trees and their associated microorganisms. Endophyte microbes can influence the health of trees either by directly interacting with the damaging agents or modulating host responses to infection. In the framework of this work, ten morphotypes of endophytic bacteria from the tissues of unripe acorns of Quercus robur L. were isolated. Based on the results of the sequenced 16S rRNA genes, four species of endophytic bacteria were identified: Bacillus amyloliquefaciens, Bacillus subtilis, Delftia acidovorans, and Lelliottia amnigena. Determining the activity of pectolytic enzymes showed that the isolates B. subtilis and B. amyloliquefaciens could not cause maceration of plant tissues. Screening for these isolates revealed their fungistatic effect against phytopathogenic micromycetes, namely Fusarium tricinctum, Botrytis cinerea, and Sclerotinia sclerotiorum. Inoculation of B. subtilis, B. amyloliquefaciens, and their complex in oak leaves, in contrast to phytopathogenic bacteria, contributed to the complete restoration of the epidermis at the sites of damage. The phytopathogenic bacteria Pectobacterium and Pseudomonas caused a 2.0 and 2.2 times increase in polyphenol concentration in the plants, respectively, while the ratio of antioxidant activity to total phenolic content decreased. Inoculation of Bacillus amyloliquefaciens and Bacillus subtilis isolates into oak leaf tissue were accompanied by a decrease in the total pool of phenolic compounds. The ratio of antioxidant activity to total phenolic content increased. This indicates a qualitative improvement in the overall balance of the oak leaf antioxidant system induced by potential PGPB. Thus, endophytic bacteria of the genus Bacillus isolated from the internal tissues of unripe oak acorns have the ability of growth biocontrol and spread of phytopathogens, indicating their promise for use as biopesticides.

Phytotesting has long been used to determine the quality of seeds, agricultural soil fertility, in biomedical research, and recently in the field of environmental protection to assess the ecological quality of natural environment (water, soil) in phytotesting of toxicants. Various plant representatives are used as model test organisms, in particular, onion (Allium cepa L.) is considered as a standard test plant for the determination of toxicants. The purpose of the work is to generalize methodological approaches of using onion (Allium cepa L.) in phytotesting of toxicants. Methodology. During the research, the following methods were used: 1) general scientific methods (methods of theoretical research of available information); 2) analytical and generalized methods (for the analysis of scientific and literature sources on the given problem); 3) empirical (for accumulating facts); 4) methods of argumentation (to prove one’s own judgments). Scientific novelty - methodical approaches of using onion in phytotesting of toxicants are summarized, formulas for calculating phytotoxic indices (root length index, phytotoxic effect of solutions, toxicity index of solutions for each test function, average toxicity index of the tested solutions) are presented. Conclusions - phytotesting is a commonly used method of assessing the quality of natural environment (water, soil) which is based on the sensitivity of plants to external chemical influences and is reflected in growth and morphological characteristics. The standard test plant for the determination of toxicant influence is the onion (Allium cepa), which can be used both in the growth test and in the Allium-test. The most sensitive characteristics of onion are the mitotic activity of the apical meristem cells and the frequency of cells with chromosomal aberrations.

Dimethyl sulfoxide (DMSO) is widely used as an industrial solvent and for a variety of medical purposes. Reports of the toxicity of DMSO to living organisms vary. The plants Lepidium sativum L. and Raphanus raphanistrum subsp. sativus (L.) Domin. are widely used in the biotesting of toxicants. Currently, there is no information on the phytotoxicity of aqueous solutions of DMSO for these test plants, which determined the aim of this study. Methodology. Phytotoxicity of aqueous DMSO solutions was assessed using a growth test. The following plants were used as test plants: 1) seed radish (R. raphanistrum subsp. sativus) of the French breakfast variety, 10 seeds of which were placed in a Petri dish on filter paper moistened with distilled water (control) or 0.5 %, 1.0 %, 5.0 %, 10.0 %, 25.0 % or 45.0 % aqueous solution of DMSO (experiment); 2) watercress (L. sativum) of the Aphrodite variety, 10 seeds of which were placed in a Petri dish on filter paper moistened with distilled water (control) or a 0.025 %, 0.05 % or 0.1 % aqueous solution DMSO (experiment). The research was carried out in triplicate for 6 days (radish) and 5 days (watercress), during which the energy of seed germination of test plants (%) was determined on the 3rd day, on the 6th day (radish) and on the 5th day (watercress) – seed germination (%) and biometric and morphometric indicators of test plant seedlings (root and aerial part length, mm). Scientific novelty. In a growth test with R. raphanistrum subsp. sativus showed extreme phytotoxicity for 5.0-45.0 % aqueous DMSO solutions and no phytotoxicity for 0.025-1.0 % aqueous DMSO solutions in a growth test with L. sativum and R. raphanistrum subsp. sativus. Conclusions. Aqueous solutions of DMSO in concentrations of 0.025-1.0 % did not show phytotoxic properties according to the growth test with L. sativum and R. raphanistrum subsp. sativus, in contrast to 5.0-45.0 % solutions, which showed extreme phytotoxicity according to the growth test with R. raphanistrum subsp. sativus. The obtained results indicate that this substance will not inhibit plant growth at concentrations found in wastewater (0.05-0.08 %).

Microorganisms cause microbiologically influenced corrosion, for the prevention of which bactericide inhibitors are used. The aim of the work was to study in vitro the sensitivity of SRB Desulfovibrio oryzae NUChC SRB1 to different concentrations of dimethyl sulfoxide (DMSO), and evaluate the indicators of the microbial corrosion of steel induced by this bacterium in the presence of the pharmaceutical drugs DMSO and paracetamol. The sensitivity of SRB D. oryzae to 1–100% DMSO (v/v) was studied via the dilution method in Postgate’s “C” liquid medium. The corrosion activity of D. oryzae against steel 3 was investigated under DMSO and paracetamol treatment at a final concentration of 45% (v/v) and 0.2% (w/v), respectively, according to the ability of bacteria to form a biofilm on the surface of the steel samples (via the crystal violet method) and the effect on the corrosion rate (via the gravimetric method). It was revealed that DMSO affected D. oryzae NUChC SRB1 and exhibited bactericidal properties (at a concentration range of 10–100%, v/v) and antibiofilm properties (at a concentration of 45%, v/v). Despite its antibiofilm properties confirmed by the reduction in bacterial biofilm mass, anticorrosion features were not observed in the model 35-day conditions of the microbial corrosion of steel in an anaerobic environment with bacterial sulfate reduction. Paracetamol (0.2%, w/v) did not affect biofilm formation by SRB under these conditions, and significantly contributed to an increase in the rate of the microbial corrosion of steel. The prospect of further research is to assess the effect of DMSO and paracetamol on the indicators of microbial corrosion induced by SRB under the influence of the concentrations of these compounds found in wastewater, to clarify the possible additional causes of damage to the equipment of treatment plants. Further research should also be directed at investigating the antimicrobial properties of complexes of compounds with DMSO, which should be considered as an ecological solution to the problem of microbiologically influenced corrosion prevention.