中国生物工程杂志

A strain ch-3, which produces cold-adapted lipase, was isolated from the frozen soil containing oil of Changji lipidic chemical plant, Xinjiang province. The morphology identification and 18S rDNA sequence analysis showed that it was Geotrichum candidum spp. and named as Geotrichum candidum ch-3. The optimal growth temperature of strain ch-3 is 20℃. Corn serum and bean oil in medium enhances the secretion of lipase. The enzyme purification was performed by double water phases extraction and gel filtration with Sephadex G-75. The optimal temperature and pH for lipase activity are 35℃ and 7.0 respectively. At 0℃, the lipase still has 66% relative enzyme activity. The lipase shows high thermolability, remaining 55% activity after incubation at 50℃ for 30min. The enzyme activity was stimulated by Fe2＋、Cu2＋、Mn2＋.