The Utilization of Certain Hydrocarbons by Microorganisms

Hydrocarbons, as a class, represent compounds with an excellent store of energy. Some idea of the available energy may be obtained by comparing the heat of combustion of some six carbon compounds. For example, glucose yields 674 Calories, as compared to 1,002 Calories from hexane. Knowledge of the biological utilization of hydrocarbons as sources of energy and carbon is fragmentary. However, various investigators have proved that a biological oxidation of these compounds can occur. Since bacterial decomposition of hydrocarbons has been established, the fact is of significance in considering the carbon cycle. The percentage of carbon in hydrocarbons varies from 80 to 89 per cent; therefore, a significant amount of the world's carbon is combined in this form. According to Egloff (1940) it is becoming more firmly established that perhaps the formation of petroleum is still going on today. The r6le of bacteria in the production of hydrocarbons is now widely accepted, although, according to Thayer (1931), there is no direct evidence that hydrocarbons of higher molecular weight than methane can be produced by their activity.