Abstract:
Carrageenan oligosaccharides are produced from the hydrolysis of carrageenans
from red seaweeds. It has been reported that there exists a correlation between
hydrolysis time and oligosaccharide size. The antibacterial properties of acid-hydrolyzed
kappa and carrageenan were pre-determined using the Kirby-Bauer method and
turbidometric study. The best antibacterial agent was subjected to a 12-hr time-kill series.
The 5% kappa carrageenan sample hydrolyzed for 30 minutes was added to cultures of
Bacillus subtilis and Vibrio cholerae. Aliquots were taken from the cultures and plated
during intervals over a 12-hr period. Populations of the bacterial cultures were estimated
using the Miles and Misra technique. The results showed that the carrageenan
oligosaccharides have antibacterial activity for both cultures. There was an initial decline
in population from the period of second to sixth hour and logarithmic growth in population
was observed from the seventh hour onwards. Statistical tests were used to correlate
oligosaccharide size with antibacterial activity. The population of the treated B. subtilis
culture was the same with the untreated culture at 12 hours. While the population of the
treated V. cholerae culture was greater compared to the untreated culture at 12 hours.
This study has concluded that only specific oligosaccharide sizes have optimal
antibacterial activity against B. subtilis and V. cholerae.
