Lipase broth cultures

If a liquid form of the enzyme is added, such as lipases in broth samples from microbial cultures, calculate specific activity on a normalized basis by substituting a ml enzyme sample added (instead of mg protein) using the equation above. 

Lipase from Yarrowia lipolytica was produced in a 2,000-1 fermentor containing (w/v) 1% of glucose, 3% of whey powder, 0.8% of ammonium sulphate, 1% of com steep syrup and 0.5% of olive oil. After 30 h of fermentation, the culture broth was centrifuged, and the supernatant was dried by lyophilization [20]. The lyophilized powder was than diluted in sodium phosphate buffer 5 mM, pH 7.0 in a final protein concentration of 0.11 mg/ml. 

Fermentation is usually followed by the removal of cells from the culture broth, either by centrifugation or by filtration (Westoby et al., 2011). The cell-free broth is then concentrated by ultrafiltration, ammonium sulfate precipitation, or extraction with an organic solvent (Saxena et al., 2003). A single purification step is usually not adequate to get lipase of high purity. Therefore, purification using a combination of chromatographic techniques is mainly employed. However, except in the pharmaceutical industry, pure lipases are required and crude enzymes are usually adequate. 

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