Purification of a Penicillium citrinum lipase by chromatographic processes

Abstract

A lipase from a wild strain of Penicillium citrinum was purified by ammonium sulphate precipitation, gel filtration chromatography on a Superose 6 column and hydrophobic interaction chromatography (HIC) on a Phenyl Superose column. The yield and purification factor were 15.2% and 379 fold, respectively. The gel filtration step was efficiently scaled-up in a Superose 6 preparative grade column and after this step, the lipase was recovered in the form of a high molecular weight aggregate. The partial disaggregation of the complex was achieved by HIC and elution with 1.0% (w/v) CHAPS. The lipase produced by Penicillium citrinum forms a dimmer of 63 000 Da, as determined by SDS-PAGE, and it accumulates in the fermentation broth as high molecular weight aggregates (>2 00 000 Da). The analysis of the dimmer showed two subunits with similar molecular weights (31 000–33 000 Da) and isoelectric points (4.8–5.0).