Factors Influencing the Heat Resistance of a Heat-Resistant Lipase of Pseudomonas

Pseudomonas spp. MC50 produced an extra-cellular lipase that was extremely heat resistant at 100–150°C when heated in water or emulsions. The D-values ranged from 40 min at 100°C to 84 sec at 150°C. The zD-vallue was 36°C. When heated in water, the lipase exhibited greatest survival at pH 8.5. Below pH 6.5, survival was less than 10% of that at pH 8.5. Survival of lipase heated in emulsions was affected somewhat by the type of oil, corn oil concentration, and type of emulsifier. Type of stabilizer or stabilizer concentration had little effect on lipase survival. Lipase treated with ethylenediaminetetraacetate (EDTA) was fully heat resistant in water; survival declined when lipase was heated in CaCl2 solutions of 3–120 mM.