Isolation of Alkaline Lipase Producing Bacteria and Studying on Fermentation Conditions and Lipase Properties

This thesis reports that a alkaline lipaseproduing bacterial strain was isolated from the oilysoil samples near the greaseproducing factory in Luzhou and was identified as Pseudomonas sp.. The lipase fermentation condition for the strain was optimized by studying on effect of nitrogen sources ,carbon sources and other influence factors. The optimal medium composition for the producing lipase (%) is: yeast extract 1.5, soybean meal 1, NaCl 0.2,K2HPO4 0.2, NaH2PO40.2, MgSO4 ·7H2O 0.01. The optimal conditions for lipase producing are initial pH8.5, cultivated aerobically at 30℃, for 48h. Then a maximum yield of 19.1 U/mL was obtained. The enzymatic characteristics included: optimum pH,8.5 value; stable pH value range, 8.0～9.5; optimum temperature, 40℃; good thermal stabilities.