Organizing co mmittee

Bacillus subtilis IMRUZ-7 - THE ACTIVE PRODUCER OF 
ALCALINE PROTEASE
 
V.V. Shurigin
1
, U.R. Rajabov
1
, A.G. Abdurakhmonov
1,2
, K. Davranov
1,2 
 
1) Institute of Microbiology of the ASc RUz, Tashkent, 100128, Uzbekistan 
2)
 
National University of Uzbekistan, Tashkent, 100174, Uzbekistan 
Proteases (KF-3.4.1.) are the most important industrial enzymes. Microbial alkaline 
proteases are of particular interest because they can be used in the manufacture of 
detergents, food, pharmaceuticals and leather. It is known that the amount of the 
produced enzyme strongly depends on the strain and its growth conditions. Among 
bacteria, 
Bacillus
spp. are specific producers of extracellular alkaline proteases. 
Microbial proteases, especially from species of the genus 
Bacillus
, have traditionally 
occupied a dominant industrial enzyme market share in worldwide enzyme sales, being 
widely used in detergent formulations. 
The aim of our research was to isolate and select the most active alkaline protease-
producing bacterial strain and to study the optimal conditions for protease production by 
the isolated bacterial strain. 
As a result of the research, we isolated proteolytic bacteria from the soil of 
slaughterhouses in the Tashkent and Bukhara regions of Uzbekistan. One of the best 
alkaline protease producers, isolate IMRUZ-7, was chosen to optimize the culture 
conditions for protease production. The bacterial isolate IMRUZ-7 was identified as 
belonging to the species 
Bacillus subtilis
based on the determination of the nucleotide 
sequence of the 16S rRNA gene. The 16S rRNA gene sequence of the isolated 
bacterium was deposited in GenBank under the number OP023837, and the strain itself 
was named 
Bacillus subtilis
IMRUZ-7. 
The nature of the growth of the strain
 B. subtilis
IMRUZ-7 on MPA: the daily culture 
is grayish-white colonies, the edges of the colonies are uneven, the surface is bumpy, 
the consistency is viscous. Microscopic examination revealed Gram-positive motile 
rods 0.5-0.6 x 3-5 µm. The strain ferments sucrose, lactose, glucose, fructose, galactose, 
maltose, does not ferment raffinose, rhamnose, inositol, sorbitol, dulcite. The strain 
hydrolyzes starch, casein, produces catalase, reduces nitrates, forms hydrogen sulfide, 
indole does not form. 
It was revealed that starch is the best cheap source of carbon, and corn broth – 
nitrogen for cultivation of 
Bacillus subtilis
IMRUZ-7 and protease production. These 
components can be used as part of an inexpensive nutrient medium for the production of 
protease. 
The maximum growth of the strain was observed when growing in a liquid nutrient 
medium with pH 8 containing starch (1%) and corn broth (0.5%) in flasks rotating at 
155 rpm for 24 h at 45°C. At the same time, the optical density of the culture at a 
wavelength of 600 nm was 1.306, and the protease activity was 343.236 u/ml 
The optimum pH and temperature for enzyme activity were determined to be 9.0 and 
60°C, respectively. Since the thermoactivity and pH stability of proteases are of great 
importance for industrial use, the enzymatic properties of the 
B. subtilis
IMRUZ-7 
protease indicate the potential use of this bacterium and its protease for various 
industrial purposes. 

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Poster presentation 
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