494
Volume 5, Issue 10: Special Issue
(EJAR)
ISSN: 2181-2020
MPHAPP
THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL
CONFERENCE
“
MODERN PHARMACEUTICS: ACTUAL
PROBLEMS AND PROSPECTS
”
TASHKENT, OCTOBER 17, 2025
in-academy.uz
THE INFLUENCE OF THE ORGANIC NITROGEN SOURCE CONTENT ON THE
ACTIVITY OF CHOLESTEROL OXIDASE PRODUCER
Shpachuk A.Yu.
Ponomarev N.D.
Khryachkova E.N.
Kolodyazhnaya V.A.
St. Petersburg State Chemical Pharmaceutical University, St. Petersburg, Russian Federation
e-mail: arkadij.shpachuk@spcpu.ru
https://doi.org/10.5281/zenodo.17343154
Background:
Cholesterol oxidase (CHO) is an enzyme from the oxidoreductase class that
catalyzes the conversion of cholesterol to cholest-4-en-3-one and hydrogen peroxide. It can be used
in test systems for determining blood cholesterol levels or as a catalyst in the synthesis of biologically
active derivatives of cholesterol. This enzyme is obtained only through microbial synthesis, during
which the selection of an optimal nutrient medium (NM) in general and the optimal content of the
organic nitrogen source, in particular, remains a very relevant issue.
Aim:
To analyze the influence of the content of the organic nitrogen source (yeast autolysate)
on the CHO activity in the mycelium of
Streptomyces lavendulae
(the producer bacterium).
Materials and methods:
The producer culture was stored in a refrigerator at 2-8°C on slanted
agar, from where a sufficient amount was transferred under aseptic conditions to a 750 ml shake flask
(volume of sterile NM – 150 ml). The producer was then cultivated for 47-48 hours at a temperature
of 28°C and a shaking speed of 210 min⁻¹. The producer's activity was measured using the Richmond
method (spectrophotometrically by the increase in optical density per minute of the catalyzed
reaction). The Plackett-Burman design (PBD) was used to assess the significance of the influence of
various factors on the cultivation results (including the factor of the organic nitrogen source content).
Results:
The PBD showed that the factor of yeast autolysate content is significant for CHO
activity in the mycelium. However, its excessive amount has a detrimental effect on the producer
(which is probably associated with the accumulation of an excess amount of ammonium in the cultural
liquid). Therefore, experiments were conducted to find the optimal content of the organic nitrogen
source. As can be seen from the presented graph, the optimum is likely somewhere between 0.7 and
0.8 g of yeast autolysate per 150 ml of NM.
Conclusions:
Thus, an understanding of the nature of the influence of the organic nitrogen
source content on the CHO activity in the
Streptomyces lavendulae
mycelium has been obtained.
495
Volume 5, Issue 10: Special Issue
(EJAR)
ISSN: 2181-2020
MPHAPP
THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL
CONFERENCE
“
MODERN PHARMACEUTICS: ACTUAL
PROBLEMS AND PROSPECTS
”
TASHKENT, OCTOBER 17, 2025
in-academy.uz
Furthermore, data providing an approximate idea of the optimal enzyme content has been obtained.
In the future, this will help in scaling up the technology to industrial conditions.
