BACTERIAL TEST PROCEDURE
In an experiment that took place over the course of 6 months at UCONN bacterial strains were chosen that would grow in petrol. One of these, Pseudomonas Oleovorens (PO) was cultured on growth medium with 2% petrol before the FFC was added on the 10th day. The FFC effectively suppresses the growth of PO as evidenced in the 2 and 8 week observations.
This figure represents the bacterial growth pattern in petrol with and without the FFC over an extended period of time. The CFU count in flask 1 increased until introduction of the FFC and then decreased with time, while flask 2 with no FFC continues to show bacterial growth.
In this investigation the researchers constructed an experiment that would measure the effect the presence of Fitch Fuel Catalyst (FFC) has on a bacteria known to degrade or breakdown fuels.
Materials and Methods
Two bacterial strains Pseudomonas oleovorans (PO) and Rhodococcus rhodochrous (RR) were selected for study. Freeze dried Pseudomonas oleovorans (ATCC29347) and Rhodococcus rhodocrous (ATCC29672) were grown in organic medium to initiate growth and verify strains. To begin adaptation of the bacteria to a petroleum carbon source, the bacteria were each grown in 50:50 salts/bacterial growth medium containing 1% petrol (Texaco 87 octane). Growth of the bacteria was monitored by plate count method. The number of colony forming units (CFU) was counted to determine a growth curve over several days to several weeks.
PO is representative of the psychotropic bacteria, those with the preference for lower temperatures and commonly found in fuels. Most bacteria that people are familiar with are the mesophilic bacteria. These require temperatures of 30°C – 40°C for growth. The particular Ps. oleovorans we obtained from the American Type Culture Collection (ATCC) had been previously isolated from machine shop cutting oils and demonstrated to be capable of utilizing alkanes. The species has also been isolated in petroleum contaminated Arctic soils.
Cultures containing fuel were prepared by adding petrol to 50 ml of Bushnell Haas Broth Salts solution (no carbon source) to 125 ml screw-cap culture flasks. The FFC was inserted into one flask on day 10.
Effects on bacterial growth
The figure shows the growth of bacteria in the presence of 2 % petrol over a 14 day period. The growth of bacteria, counted as number of ‘colony forming units’ initially increased until the FFC was added to culture 1 on day 10. Thereafter, growth of the bacteria subsided to a level below that of the control bacteria in petrol without presence of the FFC.
