UBC Theses and Dissertations
Studies of microbial hydrocarbon fermentations Guthrie, Donald James
A two part study of hydrocarbon utilization by microorganisms was undertaken. In the first part it was decided to attempt the genetic transformation of Bacillus subtilis with respect to the ability to grow on hydrocarbon carbon source. One hundred forty-four cultures of Bacillus organisms were isolated on a medium with refined kerosene as the sole carbon source. Most of these cultures were found to be B. cereus (92 isolates), B. lentus or B. firmus (15 isolates) and B. megaterium (8 isolates). Neither of the 2 strains identified as B. subtilis were capable of sufficient growth on kerosene medium, even with complex supplements added, to warrant a transformation experiment. In the second part of this study, a culture which was classified as a member of the genus Arthrobacter was investigated for its ability to grow rapidly on hydrocarbons. Dodecane was shown to be the n-alkane utilized most readily. The acidity produced by this culture was not due to formation of fatty acids, other organic acids or amino acids and was attributed to the acidity generated by utilization of the ammonium nitrogen source. When grown in a fermentor with pH control, the Arthrobacter spp. oxidized ammonia forming nitrate and nitrogen oxide gases when the dodecane carbon source was exhausted. This is the first time ammonia oxidation has been reported in an n-alkane fermentation system.