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

Abstract

AbstractCultivation of Norcardia sp., Mycobacterium phlei, and Candida lipolytica in inorganic salt solution containing n‐alkanes C10–C20 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 Ysub 60–142% and for Ye 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 C10‐C20 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.