57
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
EVALUATION OF LACTIC ACID PRODUCTION ACTIVITY OF PROBIOTIC
LACTOBACILLI
Abdulaxadova G.Sh.
Tashkent Pharmaceutical Institute, Tashkent city, Republic of Uzbekistan
e-mail: abdulakhadova.g@gmail.com
https://doi.org/10.5281/zenodo.17318338
Relevance:
Today, lactic acid is considered one of the most demanded bioproducts worldwide.
This acid is widely used in the food industry, pharmaceuticals, cosmetology, and many other sectors.
Therefore, selecting suitable raw materials and determining optimal biotechnological conditions to
increase production efficiency is one of the urgent scientific and practical tasks. Whey, a by-product
of the dairy industry, is regarded as a promising raw material for lactic acid production.
Aim of the study.
One of the important tasks is to select the most active strains of lactic acid
bacteria for efficient lactic acid production and to determine the maximum production period of lactic
acid synthesized by them. The obtained results will provide a scientific and practical basis for
optimizing the lactic acid production process, increasing economic efficiency, and developing
environmentally friendly biotechnologies.
Methods and approaches.
The amount of lactic acid was determined by a spectrophotometric
method based on the formation of a colored complex with ferric chloride (FeCl₃). In this method,
lactate ions react with FeCl₃ to form a yellow-green ferric lactate solution.
•
2 ml of 0.2% FeCl₃ solution was taken, and 50 µl of lactic acid solution was added and mixed.
•
The optical density of the resulting solution was measured at a wavelength of 390 nm (using a
1300-SF spectrophotometer).
•
A FeCl₃ solution alone was used as a control.
•
Calibration curve was constructed using standard lactic acid solutions (X-axis — optical
density, Y-axis — concentration).
•
Based on this curve, the concentration of lactic acid in the culture fluid was calculated in mg/ml
units.
Results.
The amount of lactic acid in the tested strains
P. acidilactici
1G,
P. acidilactici
2G,
L.
plantarum
3G,
L. brevis
4G, and
L. fermentum
LF1 was determined by spectrophotometry. It was
found that the highest lactic acid yield in these strains was observed on the 4th day of cultivation. On
day 1,
L. fermentum
LF1 produced 15.72 g/L of lactic acid, which increased to 40.91 g/L by day 4.
P. acidilactici
2G produced 9.72 g/L on day 1, and 18.91 g/L on day 4.
L. plantarum
3G produced
from 1.47 g/L on day 1 to 11.25 g/L on day 4.
L. brevis
4G produced 1.08 g/L on day 1 and 8.01 g/L
on day 4.
P. acidilactici
1G produced 3.02 g/L on day 1 and increased to 9.39 g/L by day 4. The study
results demonstrated that lactic acid production ability significantly varies among strains and depends
on cultivation duration. The highest producer strain was
L. fermentum
LF1, which reached 40.91 g/L
of lactic acid on day 4, while
L. plantarum
3G was the lowest producer, with 11.25 g/L on day 4.
P.
acidilactici
2G and
L. fermentum
LF1 strains also showed a significant increase in lactic acid
production.
Conclusions.
According to the results obtained by the spectrophotometric method, lactic acid
production capacity depends on the genetic characteristics of the strain and cultivation conditions.
L.
fermentum
LF1 strain produced the highest amount of lactic acid and is recommended as the most
promising strain for applications in medicine, agriculture, and the food industry.
