Lipase, from porgy (Stenotomus chrysops) viscera, was purified by polyethylene glycol (PEG) 1000 precipitation, followed by dialysis and affinity chromatography on EAH-Sepharose 48. The digestive lipase from porgy showed seasonal variation in activity with high activity found in late summer and early fall compared with a spring sample. Polyethylene glycol (PEG) precipitation fraction was used to characterize this enzyme using p-nitrophenyl palmitate (pNPP) as substrate. Porgy lipase did not behave like a bile salt activated/depended lipase because it was able to hydrolyze pNPP without bile salt (e.g., sodium cholate). Porgy lipase was stable within the pH range of pH 6.0-10.0, with an optimum activity at pH 8.5. The enzyme was quite stable at temperatures below 40°C, but lost its activity rapidly at temperatures above 40°C. The optimum activity for hydrolysis pNPP was at 40°C, but the enzyme also demonstrated relatively high activity at temperatures below 40°C (i.e., 10-40°C) as well. Detergents, Triton X-100, Tween 40 and Tween 80, at final concentrations of 0.5 mM and 1 mM were found to have inhibitory effects on porgy digestive lipase activity. However, all three tested detergents appeared to increase the activity of porgy digestive lipase at elevated temperatures (i.e., 60-80°C).

No description available.

No description available.

Induction of extracellular lipases from Pseudomonas fragi CRDA 037 and Geotrichum candidum was used to increase lipase production in a shorter period of time. Induction was performed using edibles oils such as olive oil, canola oil, fish oil and butter fat. Fermentation trials of the microorganisms in the selected media were done in order to optimize the production of lipases. Optimal lipase activity was obtained in the presence of butter fat (1%, v/v) for P. fragi which was cultivated at 15°C during 48 h, and fish oil (0.75%, v/v) for G. candidum incubated at 27°C for 56 h. The induced lipase extracts of P. fragi and G. candidum obtained after these fermentation trials were purified by 3.7 and 5.9-fold respectively using ultrafiltration, while the non-induced fractions were purified by 2.3 and 5.1-fold, respectively. Activities were evaluated using p-nitrophenyl esters such as p-nitrophenyl laurate and p-nitrophenyl palmitate. (Abstract shortened by UMI.)

No description available.