Introduction. Now surfactants of microbial origin due to the unique properties are promising for use in many sectors of the economy: to increase oil production, to provision specific taste and structural properties of food and in bioremediation processes of ecosystems.
Widespread use of microbial surfactants is constrained by high costs on biosynthesis (materials, energy) and the isolation and purification of the final product. One way to reduce the cost of production is use less expensive substrates, including waste from other industries.
New perspective area of biotechnology is to obtain and use complex microbial preparations with different properties, such as complex microbial surfactants with enzymes, bacteriocins, polysaccharides [1].
The aim of the work. To study the possibility of synthesis extracellular compounds with gibberellic activity by producers of surfactants A. calcoaceticus IMV B-7241 and R. erythropolis IMV Ac-5017. Materials and methods. Bacteria were cultivated using a synthetic medium. Fried and refined sunflower oil (restaurant chain McDonald's, Kyiv), technical glycerol (Komsomolsk biofuel factory, Poltava region), ethanol and hexadecane were used as the carbon source. Substrate concentration was 2% (v/v).
Phytohormones of gibberellic nature were extracted from the supernatant culture liquid A. calcoaceticus IMV B-7241 and R. erythropolis IMV Ac-5017 after isolation of surfactants using mixture of chloroform and methanol in a ratio of 2:1 (Folch’s mixture). Preliminary purification and concentration of the substances with gibberellic activity was performed by thin layer chromatography method.
To determine gibberellic activity we used hypocotyls of seedlings of cucumber grade Nezhinskiye. After germination of cucumber seeds during 3-4 days (temperature 27 °C) hypocotyls with length 2,0 ± 0,2 cm were selected. Hypocotyls were placed in Petri dishes with aliquots of aqueous solutions of extracts at dilutions 1:500 and 1:600. After incubation for 1-2 days at 27 °C elongation of hypocotyls was measured and was compared to controls (treatment with distilled water and a solution gibberellic acid (GA3) at a concentration of 10-5 M).
Results and discussion. Treatment of cucumber seedling grade Nezhinskiye by extracts with substances of gibberellic nature synthesized by strains IMV B-7241 and IMV Ac-5017 was accompanied by a positive effect on hypocotyls elongation (table 1).
Note. Incubation of seedlings after their treatment with relevant extracts was 1 day (*) or 2 days (**) The highest growth rates were observed in case of treatment cucumber seedlings with extract containing metabolites synthesized by A. calcoaceticus IMV B-7241 on refined oil and by R. erythropolis IMV Ac-5017 - on ethanol.
In the available literature we could not find information about the synthesis of phytohormones, including gibberellins, by producers of surfactants. Meanwhile the ability to synthesize gibberellins found in many microorganisms including fungi genera Fusarium, Sphaceloma and Phaeosphaeriae and bacteria genera Bacillus, Acinetobacter, Bradyrhizobium, Sinorhizobium and Mesorhizobium [2, 3].
Conclusion. Thus, for the first time the possibility of surfactant producers to synthesize extracellular exometabolites with gibberellic activity was established. The obtained data are the basis for development of technology of complex microbial preparations with different biological properties.
Table 1 - Hypocotyls length (cm) of cucumbers grade Nezhinskiye after treatment with extracts obtained from the supernatant culture liquid A. calcoaceticus IMV B-7241 and R. erythropolis IMV Ac-5017
|
Strain |
The growth substrate |
Control (water) |
Gibberellic acid |
Dilution of extract |
|
|
1:500 |
1:600 |
||||
|
IMV B-7241 |
Ethanol * |
4,26 ± 0,40 |
4,60 ± 0,40 |
4,70 ± 0,36 |
4,84 ± 0,30 |
|
Technical glycerol * |
4,66± 0,38 |
5,84 ± 0,30 |
4,95 ± 0,40 |
5,28± 0,35 |
|
|
Refined oil * * |
10,20 ± 0,20 |
11,40 ± 0,40 |
11,10 ± 0,32 |
11,30 ± 0,33 |
|
|
Waste oil after frying meat ** |
8,90 ± 0,40 |
9,80 ± 0,35 |
9,50 ± 0,40 |
9,08 ± 0,37 |
|
|
IMV Ac-5017 |
Ethanol * |
4,70 ± 0,20 |
5,88 ± 0,28 |
5,58 ± 0,18 |
6,00 ± 0,30 |
|
Hexadecan * |
5,40 ± 0,40 |
6,00 ± 0,20 |
5,70 ± 0,40 |
5,80 ± 0,40 |
|
|
Refined oil * |
5,70 ± 0,25 |
6,54 ± 0,24 |
6,50 ± 0,30 |
6,80 ± 0,30 |
|
|
Waste oil after frying meat * |
5,80 ± 0,40 |
6,60 ± 0,30 |
7,20 ± 0,20 |
6,90 ± 0,30 |
|
References
1. Bhangea K., Chaturvedib V., Bhatta R. Simultaneous production of detergent stable keratinolytic protease, amylase and biosurfactant by Bacillus subtilis PF1 using agro industrial waste // Biotechnology Reports, 2016, Vol. 10, p. 94-104.
2. Hedden P., Thomas S.G. Gibberellins in fungi, bacteria and lower plants: biosynthesis, function and evolution // Annual Plant Reviews, 2016, V. 49, p. 472.
3. Hedden P., Sponsel V.A. Century of Gibberellin Research // J. Plant Growth Regul, 2015, Vol. 34, N 4, p. 740-760.