OIL BIODEGRADATION BY CONSORTIUM OF OIL DEGRADING MICROORGANISMS IN LABORATORY MODEL SYSTEMS

Abstract. Aim. To evaluate the effectiveness of a consortium of hydrocarbon oxidizing bacteria in various model systems. Methods. Two types of model systems were used for carrying out the experiments: with a liquid mineral medium and with non-sterile soil. To determine the number of microorganisms, a standard method of serial dilutions with seeding to individual colonies was used. Individual strains in the consortium were distinguished using selective media with antibiotics. Oil degradation was assessed by IR spectrometry. Results. The consortium was capable to effective oil destruction in a liquid medium at 4°C and at 24°C, and with respect to control, oil loss is higher at low temperature. At 50°C, the consortium was inactive. In model non-sterile soil systems, the stimulation of native microorganisms by introducing mineral fertilizers did not lead to significant changes in the number of oil-degrading microorganisms but the degree of oil degradation increased. With the joint introduction of the microbial consortium and fertilization, the greatest number of both heterotrophic and oil-degrading strains was observed in the soil system. The degree of oil destruction in this system was also the highest: 59% at 42 days at room temperature. Main conclusions. The developed bacterial consortium has a high oil-degrading activity both at low (4°C) and moderate (18-25°C) temperatures. In non-sterile soil systems, the consortium's microorganisms do not inhibit the local biota, maintaining their numbers at about constant levels, but at the same time they make the main contribution to pollution degradation

Capture of Essential Trace Elements and Phosphate Accumulation as a Basis for the Antimicrobial Activity of a New Ultramicrobacterium—Microbacterium lacticum Str. F2E

Microbial interactions play an important role in natural habitat. The long-term coevolution of various species leads to the adaptation of certain types of microorganisms as well as to the formation of a wide variety of interactions such as competitive, antagonistic, pathogenic and parasitic relationships. The aim of this work is a comprehensive study of a new ultramicrobacterium Microbacterium lacticum str. F2E, isolated from perennial oil sludge, which is characterized by high antimicrobial activity and a unique ultrastructural organization of the cell envelope, which includes globular surface ultrastructures with a high negative charge. A previously undescribed mechanism for the antagonistic action of the F2E strain against the prey bacterium is proposed. This mechanism is based on the ability to preferentially capture essential microelements, in which charge interactions and the property of phosphate accumulation may play a significant role. The revealed type of intermicrobial interaction can probably be attributed to the non-contact type antagonistic action in the absence of any diffuse factor secreted by the antagonistic bacteria

Whole-Genome Sequencing and Biotechnological Potential Assessment of Two Bacterial Strains Isolated from Poultry Farms in Belgorod, Russia

Bacteria, designated as A1.1 and A1.2, were isolated from poultry waste based on the ability to form ammonia on LB nutrient medium. Whole genome sequencing identified the studied strains as Peribacillus frigoritolerans VKM B-3700D (A1.1) and Bacillus subtilis VKM B-3701D (A1.2) with genome sizes of 5462638 and 4158287 bp, respectively. In the genome of B. subtilis VKM B-3701D, gene clusters of secondary metabolites of bacillin, subtilisin, bacilisin, surfactin, bacilliacin, fengycin, sactipeptide, and ratipeptide (spore killing factor) with potential antimicrobial activity were identified. Clusters of coronimine and peninodin production genes were found in P. frigoritolerans VKM B-3700D. Information on coronimine in bacteria is extremely limited. The study of the individual properties of the strains showed that the cultures are capable of biosynthesis of a number of enzymes, including amylases. The B. subtilis VKM V-3701D inhibited the growth of bacterial test cultures and reduced the growth rate of the mold fungus Aspergillus unguis VKM F-1754 by 70% relative to the control. The antimicrobial activity of P. frigoritolerans VKM V-3700D was insignificant. At the same time, a mixture of cultures P. frigoritolerans VKM B-3700D/B. subtilis VKM B-3701D reduced the growth rate of A. unguis VKM F-1754 by 24.5%. It has been shown that strain A1.1 is able to use nitrogen compounds for assimilation processes. It can be assumed that P. frigoritolerans VKM V-3700D belongs to the group of nitrifying or denitrifying microorganisms, which may be important in developing methods for reducing nitrogen load and eutrophication