An identifiedEnterobacter aerogenesutilizing methanol as a sole carbon source was studied for the optimization of biomass production and the reduction of its nucleic acid content. Results indicated that the highest yield and conversion were obtained at 0.5% methanol. The addition of seawater as a source of trace elements has an adverse effect. However, the addition of urea as source of nitrogen enhanced the growth of E. aerogenes. Heat shock at 60 degrees C for 1 min followed by incubation at 50 degrees C for 2 h caused 72.6% reduction in the nucleic acid.