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.
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
Tej
T
Bhatnagar
Saad
S
Boutaiba
Hocine
H
Hacene
Jean-Luc
JL
Cayol
Marie-Laure
ML
Fardeau
Bernard
B
Ollivier
Jacques C
JC
Baratti
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