PhD doctor Amirasheva B.К¹., Rahimbaeva А²., Kaldybekova R.E.², Amirasheva L.К¹

Institute of microbiology and virology CS МES RK

Kazakh national pedagogical university named after Abay

Emulsifying activity halotolerant strains of bacteria isolated from oil reservoirs deposit "KAZRUSOIL" Kyzylorda region

Abstract. From an oil reservoir oil wells "KazRosOil" allocated 17 bacterial strains are selected 3 strain (12RZH, 13RZH, 14RZH) able to grow at 10% NaCI, and 3 of culture (12RZH, 13RZH, 14RZH) has a high emulsifying activity.

Keywords: oil reservoirs, strain, halotolerant bacterium, emulsifying activity

Currently, high-viscosity oil is regarded as the main reserve of world oil production. Its reserves of about 5 times higher than the recoverable oil reserves of low and medium viscosity. Existing technologies allow extracting only half of the oil contained in the oil fields. Currently still in the depths of more than 70% of oil reserves. In this regard, markedly increased interest in finding ways and means of enhancing secondary oil recovery and in particular to the microbiological methods. At the present stage the task EOR clean technologies can solve the method of microbial stimulation. Unlike chemical reactants lose activity as a result of dilution with formation water, the microorganisms are capable of self-development, i.e. reproduction and reinforcement biochemical activity, depending on the physical and chemical conditions of the environment.

As a result of microbiological synthesis directly in the reservoir formed metabolites such as gases, acids, surfactants, thereby reducing the viscosity of the oil and enhanced oil recovery by 40%. Practical application of biotechnology allows 5-7% increase in stocks involved in the design, 1.5-2 times increase the productivity of wells, and current oil production - by 15-25%. With ever rising energy prices biotechnological methods pay off within 1.5-2 years [1].

The possibility of using a microbiological effects in order to increase oil recovery and oil production intensification first patented C.E Zobell (1946) [2], is now confirmed by many researchers and successful fishing experiments [3-5].

One of the most effective oil displacement agents are biosurfactants. Due to its physical and chemical properties, the ability to exercise them in the presence of high concentrations of salts and is not adsorbed on the limestone and sandstones, bioemulsifiers, mixed with other, for example, nonionic surfactants, can be an effective means of increasing oil production [6-10]. Introduction of the surfactant-producing microorganisms in an oil field, followed by breeding them and form a seam directly bioSAS significantly affect oil displacement.

Biogenic surfactants synthesized by bacteria, yeasts, microalgae and some mitsellialnymi mushrooms. The most studied biosurfactants bacteria Pseudomonas aeruginosa, Rhodococcus erythropolis, Bacillus licheniformis, B. subtilis, B. brevis, B. polimixa, Acinetobacter calcoaceticus, and yeast Torulopsis [11-14].

When using microorganisms for enhanced oil recovery, it is important to input strains exhibited high tolerance to salinity. In this connection, the allocated halotolerant bacteria investigated.

The purpose of research - definition of emulsifying activity halotolerant microorganisms isolated from oil reservoirs deposits "KazRusOil" of Kyzylorda region.

Materials and methods

Object of recearch is the samples of oil reservoirs deposits "KazRosOil" Kyzylorda region.

Isolation of microorganisms from halotolerant oil reservoirs Kyzylorda region was performed by enrichment cultures on medium-Voroshilova Dianova (VD) of the following composition (g/l) NH4NO3 - 1,0, K2HPO4 - 1,0, KH2PO4 - 1,0, MgSO4 - 0, 2, CaCl2 · 6H2O - 0,02, FeCl3 - traces, pH = 7,0-7,2. As carbon and energy source oil used in an amount of 1%.

Impact factor salinity on the growth of strains studied on agar medium supplemented with different salt concentrations: 3%, 5%, 7%, 10% NaCI.

Emulsifying activity of the culture medium was determined by Iguchi [15]. As used hexadecane, hydrophobic substrate.

Results and discussion

A search for halophilic microorganism cultures isolated from hot oil reservoirs deposits "KazRusOil" of Zhusaly area, well №5, at a depth of 610-640 m. Total allocated 17 strains: 1RZH, 2RZH, 3RZH, 4RZH, 5RZH, 6RZH, 7RZH, 8RZH , 9RZH 10 AJ 11RZH, 12RZH, 13RZH, 14RZH, 15RZH, 16 RZH, 17RZH.

The test results showed that all of the culture grown at 3-5% salt content in the medium. Increasing the salt concentration up to 7% of the strains was kept: 1RZH, 3RZH, 4RZH, 6RZH, 7RZH, 11RZH, 12RZH, 13RZH, 14RZH, 15RZH (Table 1).

Table 1 - Results of the salt content in the medium of cultured microorganisms

Strain	NaCl concentration
	3%	5%	7%	10%
1	2	3	4	5
1 RZH	++++ ++++	++++ ++++	++ ++	---- ----
2 RZH	++++ ++++	++++ ++++	++ ++	---- ----
3 RZH	++++ ++++	++++ ++++	++ ++	---- ----
4 RZH	++++ ++++	++++ ++++	++ ++	---- ----
5 RZH	++++ ++++	++++ ++++	++ ++	---- ----
6 RZH	++++ ++++	++++ ++++	++ ++	--- ---
7 RZH	++++ ++++	++++ ++++	++ ++	--- ---
8 RZH	++++ ++++	++ ++	--- ---	--- ---
9 RZH	++++ ++++	++++ ++++	--- ---	--- ---
10 RZH	++++ ++++	++++ ++++	--- ---	--- ---
11 RZH	++++ ++++	++++ ++++	++ ++	--- ---
12 RZH	++++ ++++	++++ ++++	++++ ++++	+++ +++
13 RZH	++++ ++++	++++ ++++	++++ ++++	+++ +++
14 RZH	++++ ++++	++++ ++++	++++ ++++	+++ +++
15 RZH	++++ ++++	++++ ++++	+++ +++	--- ---
16 RZH	++++ ++++	++++ ++++	++ ++	--- ---
17 RZH	+++ +++	++ ++	++ ++	--- ---
Note - (-) - lack of growth, (++) - moderate growth (+++) - good growth, (++++) - abundant growth

It was found that at a concentration of 10% NaCl, the ability to grow was observed in strains 12RZH, 13RZH, 14RZH (Figure 1).

Figure 1 - The growth of the strains in the presence of 10% NaCl

The relatively high rate control emulsifying activity among isolated from oil reservoirs bacterial cultures showed strains: 1RZH, 12RZH, 13RZH, 14RZH, 16RZH after 2 days emulsifying activity was 0,449-0,638 units. OD620, and then on the seventh day has risen to 0,615-1,212 units. OD620. The remaining strains EA was significantly lower, and the strain 4RZH activity practically does not show.

Thus, it was found that strains (1RZH, 12RZH, 13RZH, 14RZH, 16RZH) had a high degree of isolation thanks to EA bioSAS in medium. These strains are promising for further research on their use in enhanced oil recovery.

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