Biomedical Engineering Reference
In-Depth Information
Submerged fermentation of antagonistic strain was carried out at temperature 30ºС on the
nutrient medium with molasses as the carbon source in Erlenmeyer flasks on the shaker (180-
200 rpm), in lab fermenters ANKUM-2M of 70 l capacity, industrial bioreactors of 30 l and
100 l volume at aeration rate 1.0 lair/l medium min and agitation rate 200 rpm.
In experiments on optimization of
B. subtilis
B 454D fermentation conditions in lab
fermenter ANKUM-2M growth temperature and aeration rates were varied in the following
range -30-34ºC and 0.8-1.2 l air/l·min at agitation rate 200 rpm. For each operational regimen
growth parameters were calculated and dynamics of antagonistic activity was monitored.
Microbiological and biochemical control of culture development and accumulation of
antimicrobial metabolites was performed by taking and analyzing samples of cultural broth,
and sporulation process was observed by microscopy.
Finite dilutions technique was applied to estimate bacterial cell titer [10]. Spore
concentration was evaluated by the same method upon heating of bacterial suspension at 80ºC
during 70 min.
Antagonistic activity of bacteria was assessed by wells [11] and replica methods [12].
Interaction of bacterial antagonists with normal gut flora species was investigated by
wells technique, using bifido-and lactobacteria as test cultures [11].
Adhesive properties of bacilli were analyzed according to V.Brilis and H.Lentzner [13]
where ram and human erythrocytes stabilized with glutaric aldehyde served as a model.
Toxicological Bacinil trials were conducted at the department of cattle diseases and lethal
infections, at vivarium of Institute of Experimental Veterinary Research.
Qualitative and quantitative make-up of gut microbiota in healthy laboratory animals was
established by inoculating small intestine contents of mice aged 1 month and weighing 20-22
g onto selective nutrient media. Studies on Bacinil efficiency were carried out at department
of viral infections, Institute of Experimental Veterinary Research and at Belarusian farms.
The following parameters were controlled: duration of pathology, number of recovered
animals, therapeutic efficiency, body weight gains in test and control cattle. Large-scale tests
to evaluate Bacinil efficiency for prevention and treatment of gastrointestinal and respiratory
diseases were conducted at bull breeding complex Vishnyovka 2002, Minsk region.
The obtained results were analyzed using Microsoft Excel software. Statistical processing
of experimental data implied determination of arithmetical means and their confidence ranges
for probability level 95%.
R
ESULTS AND
D
ISCUSSION
In accordance with obtained findings (Table 1) strain
B. subtilis
B-454 D is able to
control spreading of broad spectrum of animal pathogens. Antibacterial action of the culture
is expressed as growth inhibition zones of pathogenic bacteria ranging from 20.0 to 31.5 mm
in diameter.
It was established by comparative analysis of B. subtilis B454 D antagonistic activity
with antagonists of genus
Bacillus
, namely
B. subtilis
BKM 4759 D-active principle of
Subalin preparation that the studied culture is not infection to foreign analogs in spectrum of
antagonistic activity, and with respect to certain test cultures (
Pasterella multacda, Proteus
vulgaris
) exceeds them [14] evidencing good application potential of selected strain for
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