On Further Study of Extracellular Accumulation of DNA by Hydrocarbon-utilizing Pseudomonas Species

Abstract

Extracellular accumulation of high molecular weight DNA was further studied using Pseudomonas species. More efficient production was obtained by the use of glucose-grown seed culture and by controlling the broth-pH at around 6.0 for first 24hr and then around 8.0 during the fermentation. The maximum yield was 5 to 6g per liter of the broth culture, which corresponded to 10-fold of that reported in the previous work.
Purified DNA (4×10⁶ daltons) was obtained successfully by applying an aqueous biphase system of dextran-polyethyleneglycol and dextranase.
Significant release of DNA occurred only with cell lysis of n-paraffin-grown bacteria. The primary cause of rapid lysis was explained by the exhaustion of cellular glucose pool. Relation of DNA accumulation to the effect of rhamnolipids on cell membrane was also investigated.