Kinetic modeling, production and characterization of an acidic lipase produced by Enterococcus durans NCIM5427 from fish waste.

Enterococcus durans NCIM5427 (ED-27), capable
of producing an intracellular acid stable lipase, was isolated
from fish processing waste. Its growth and subsequent lipase
production was optimized by Box Behneken design (optimized
conditions: 5 % v/v fish waste oil (FWO), 0.10 mg/ml
fish waste protein hydrolysates (FWPH) at 48 h of fermentation
time). Under optimized conditions, ED-27 showed a 3.0
fold increase (207.6 U/ml to 612.53 U/ml) in lipase production,
as compared to un-optimized conditions. Cell growth and
lipase production wasmodeled using Logistic and Luedeking-
Piretmodel, respectively; and lipase production by ED-27 was
found to be growth-associated. Lipase produced by ED-27
showed stability at low pH ranges from 2 to 5 with its optimal
activity at 30 °C , pH4.6; showedmetal ion dependent activity
wherein its catalytic activity was activated by barium, sodium,
lithium and potassium (10 mM); reduced by calcium and
magnesium (10 mM). However, iron and mercury (5 mM)
completely inactivated the enzyme. In addition, modifying
agents like SDS, DTT, β-ME (1%v/v) increased activity of
lipase of ED-27; while, PMSF, DEPC and ascorbic acid
resulted in a marked decrease. ED-27 had maximum cell
growth of 9.90309 log CFU/ml under optimized conditions
as compared to 13 log CFU/ml in MRS. The lipase produced
has potential application in poultry and slaughterhouse waste
management.