Facultative alkaliphiles lack fatty acid desaturase activity and lose the ability to grow at near-neutral pH when supplemented with an unsaturated fatty acid.
Two obligate alkaliphiles were found to have high levels of fatty acid desaturase, whereas two facultative alkaliphiles had no detectable activity. Supplementation of the growth medium of one facultative strain with palmitoleic acid, but not palmitic acid, at pH 7.5 inhibited growth. The obligate strain outgrows the facultative strain in a chemostat at a very high pH, whereas the converse is true at a pH of 7.5, and the two strains grow equally well at pH 9.0. Thus, the obligate strain is compromised at a near-neutral pH but is better adapted than a related facultative alkaliphile to an extremely alkaline pH.
Dunkley
E A
EA
Department of Biochemistry, Mount Sinai School of Medicine, City University of New York, New York 10029.
Guffanti
A A
AA
Clejan
S
S
Krulwich
T A
TA
D001407:Bacillus / Q000201:enzymology* / Q000254:growth & development; D003470:Culture Media; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007848:Laurates / Q000494:pharmacology; D010169:Palmitic Acids / Q000494:pharmacology
D003470:Culture Media; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D007848:Laurates; D010169:Palmitic Acids; C008757:palmitoleic acid; D044943:Fatty Acid Desaturases