Lipolytic activity from Halobacteria: screening and hydrolase production.
Strains of Halobacteria from an Algerian culture collection were screened for their lipolytic activity against p-nitrophenyl butyrate (PNPB) and p-nitrophenyl palmitate (PNPP). Most strains were active on both esters and 12% hydrolyzed olive oil. A strain identified as Natronococcus sp. was further studied. It grew optimally at 3.5 M NaCl, pH 8 and 40 degrees C. An increase in temperature shifted the optimum salt concentration range for growth from a wider range of 2-4 M, obtained at 25-30 degrees C, to a narrower range of 3.5-4 M, obtained at 35-40 degrees C. At 45 degrees C the optimum salt concentration was 2 M. These results show a clear correlation between salt and temperature requirement. The optimum conditions for the production of hydrolytic activity during growth were: 3.5 M NaCl and pH 8 for PNPB hydrolytic activity and 4 M NaCl and pH 7.5 for PNPP hydrolytic activity; both at 40 degrees C. The clear supernatant of cells grown at 4 M NaCl showed olive oil hydrolysis activity (in presence of 4 M NaCl) demonstrating the occurrence of a lipase activity in this strain. To our knowledge, this is the first report of a lipase activity at such high salt concentration.
Bhatnagar
Tej
T
Laboratoire de Biocatalyse et Chimie Fine, UMR 6111, Université de la Méditerranée, Faculté des Sciences de Luminy, 163, Avenue de Luminy, Case 901, 13288, Marseille Cedex 9 France. bhatnaga@luminy.univ-mrs.fr
Boutaiba
Saad
S
Hacene
Hocine
H
Cayol
Jean-Luc
JL
Fardeau
Marie-Laure
ML
Ollivier
Bernard
B
Baratti
Jacques C
JC
D002087:Butyrates / Q000378:metabolism; D019605:Euryarchaeota / Q000201:enzymology*; D005227:Fatty Acids / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000378:metabolism*; D019634:Natronococcus / Q000201:enzymology / Q000254:growth & development; D010168:Palmitates / Q000378:metabolism; D012965:Sodium Chloride; D013696:Temperature
D002087:Butyrates; D005227:Fatty Acids; D010168:Palmitates; C050015:4-nitrophenyl palmitate; C033592:4-nitrophenyl butyrate; D012965:Sodium Chloride; D006867:Hydrolases