Microbial transformation of hydrocarbons. II. Growth constants and cell composition of microbial cells derived from n‐alkanes

Cultivation of Norcardia sp. , Mycobacterium phlei , and Candida lipolytica in inorganic salt solution containing n ‐alkanes C 10 –C 20 as solo carbon and energy source was investigated. Generation times of 0.5–7.0 hr were typical during the exponential growth phase. The final cell concentrations (dry weight) were usually 9–26 g/l with n ‐alkane mixtures ranging from n ‐decane through n ‐eicosane. A linear dependence was found between the production of cell mass and the consumption of n ‐alkanes. The rest concentration of n ‐alkanes in the cell mass is in all experiments smaller than 0.5% (w/w). Cell yields were Y sub 60–142% and for Y e 50–97% based on n ‐alkane utilization. In one case, with the Nocardia NBZ 23, the substrate specifity on hydrocarbons and on a n ‐alkane mixture C 10 ‐C 20 was studied. The cell mass recovered from the fermentations contained 47.8–57.7% carbon, 5.6–9.95% nitrogen, 7.2–9.4% hydrogen, 35–62% crude protein, and 6–36% lipid. Cellular protein and lipid synthesized by an organism is influenced by the type of nitrogen source. The amino acid, glucosamine, muramic acid, 2,6‐diaminopimelinic acid, and fatty acid distribution in organisms grown on n ‐alkanes compared with a corresponding fermentation on glucose as sole carbon source were also estimated.