COMPARATIVE STUDIES ON THE TIME OF INUCULATION, ENRICHMENT CYCLE, AND SERIAL DILUTION ON THE BIOSURFACTANT PRODUCTION OF PSEUDOMANAS aeruginosa

Abstract

This study aimed at comparative study on the effects of time of inoculation, enrichment
cycle, and serial dilution on the bio surfactant production by Pseudomonas aeruginosa.
The study was conducted on a batch of cultures from Pseudomonas aeruginosa. The
inocula (inoculum sizes) were inoculated at different times 0hr, & 24hrs), with different
enrichment cycle (three cycles), and various serial dilutions (2,4 & 6). Screening for
Biosurfactant production was carried out such as Emulsification index, Haemolytic
activity ,Oil displacement, Rhamnose test, Foam activity and Viscosity reduction
test.Statistical analysis among the three different methods of Pseudomonas
aeroginosashowed that the time of inoculation had a significant effect on biosurfactant
production. The highest biosurfactant production was observed when the inoculation time
was delayed up to 24 hours. Beyond that, biosurfactant production decreased, indicating
that an early inoculation could inhibit the biosurfactant production process. Regarding the
enrichment cycle, it was found that increasing the number of cycles resulted in higher
biosurfactant production, up to a certain point. The optimal enrichment cycle was
determined to be three cycles, after which the production plateaued. The serial dilution
technique also exhibited a notable impact on biosurfactant production. Lower dilution
ratios (higher initial cell densities) correlated positively with increased biosurfactant
production.The results from the enrichment cycle, serial dilution, and direct inoculation of
crude oil showed that setup A1 had the shortest enrichment cycle of 4 days and direct
inoculation. It resulted in the highest biosurfactant productivity. In contrast, setup A2 had
a longer enrichment cycle of 7 days and no direct inoculation, resulting in lower
biosurfactant productivity. Setup A3 had a moderate enrichment cycle of 5 days and direct
inoculation, resulting in a high biosurfactant productivity. The findings of this study
provide insight into the microbial production of bio surfactants, and the possible effects
of the parameters mentioned on their production.Conduct further investigations to
explore the underlying mechanisms responsible for the observed effects of time of
inoculation, enrichment cycle, and serial dilution on biosurfactant production. This could
involve molecular studies, gene expression analysis, or proteomic analysis of
Pseudomonas aeruginosa.