Alkaliphile - Background Information

Background Information

Microbial growth in alkaline conditions presents several complications to normal biochemical activity and reproduction, as high pH is detrimental to normal cellular processes. For example, alkalinity can lead to denaturation of DNA, instability of the plasma membrane and inactivation of cytosolic enzymes, as well as other unfavorable physiological changes. Thus, in order to adequately circumvent these obstacles, alkaliphiles must either possess specific cellular machinery which functions optimally in the alkaline range or they must have methods of acidifying the cytosol in relation to the extracellular environment. In order to determine which of the above possibilities are, in fact, employed by alkaliphiles, experimentation has been carried out which demonstrated that alkaliphilic enzymes possess relatively normal pH optimums. The determination that these enzymes function most efficiently near physiologically neutral pH ranges (about 7.5-8.5) was one of the primary steps in elucidating how alkaliphiles survive intensely basic environments. Because the cytosolic pH must remain nearly neutral, alkaliphiles must have one or more mechanisms of acidifying the cytosol when in the presence of a highly alkaline environment.