FIG. 1.

Extracellular lipase activity during growth at pH^60°C 7.6 (A) and pH^60°C 9.0 (B). Optical density (O.D.; curve) and specific activity (bars) in units of activity per mg protein in the supernatant which contained 0.75% yeast extract (wt/vol), leading to a high protein value and thus low specific activity. Error bars show standard deviations. A 500-ml amount of anaerobic medium was inoculated with 5% (vol/vol) of a 12-h-old culture of T. lipolytica, the pH of the medium was adjusted by using 0.2 M HCl and 0.2 N NaOH, and the culture was incubated at 60°C. Every time a sample was withdrawn, the pH of the culture was adjusted. After the optical density was measured, the sample was centrifuged and used for protein quantification and lipase assays.