Cell surface hydrophobicity and assimilation of hexadecane by Pseudomonas frederiksbergensis

A study was undertaken to investigate the mechanisms for biosurfactant-enhanced hexadecane uptake into P. frederiksbergensis. Biosurfactants production was observed within 4-6 days from the incubation. The biosurfactant(s) were able to cause a drop in the surface tension from 72 to 25 mNm^-1 after 10 days of incubation. The stability of hexadecane emulsion in the supernatant of the culture was observed after 24 h, where 15 % of the hexadecane was converted to an emulsion. After 8 days, the conversion reached maximum value of 73.3 % when the adhesion of the cells to hexadecane was 88%. This study supports the hypothesis of alkane transport into microbial cells by direct contact with larger alkane droplets and by pseudosolubilization. Also, it appears that both mechanisms occur simultaneously.