Highly Persistent Strains of Hydrocarbon-Oxidizing Bacteria as a Base for Increasing the Viable Cell Numbers during Long-Term Storage
2021
Nikolaev, Yu. A. | Loiko, N. G. | Demkina, E. V. | Borzenkov, I. A. | Kanapatskii, T. A. | El’-Registan, G. I.
Due to frequent and large-scale oil spills, increasing the stability of biopreparations with hydrocarbon-oxidizing bacteria (HOB), which are used for bioremediation of oil-contaminated environmental objects, is presently an important task. In the present work, a new approach for maintaining the viable HOB cell titer under unfavorable storage conditions (oxygen availability at 18−24°C) was developed, which implies constructing a strain with increased number of persister cells (High Persistence Strain, HPS). The HPS of a HOB bacterium Acinetobacter seifertii WS1 was obtained by antibiotic selection with ciprofloxacin. The share of persister cells in the population increased after 13 sequential selection cycles from 1.2 to 52%. Several months of storage of the A. seifertii HPS resulted in 2−4 times better survival than in the control. The new strain retained ability to produce high numbers of persister cells after numerous transfers without antibiotic selection. The rate of oil oxidation by the HPS culture after 4-month storage was 2−4 times higher than in the control culture. The developed approach to increasing the viable cell titer of long-term-stored cells has not been applied previously and may be used in ecobiotechnology.
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