Adv Biochem Eng Biotechnol (2020) 172: 85–134
DOI: 10.1007/10_2019_97
© Springer Nature Switzerland AG 2019
Published online: 5 July 2019
Challenges and Adaptations of Life
in Alkaline Habitats
Gashaw Mamo
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
2 The Grand Challenges to Thrive in Alkaline Habitats from a Neutralophilic
Standpoint . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . 89
3 Adaptation of Alkaliphiles: Circumventing the Challenges of Alkalinity . . . . . . . . . . . . . . . . . 92
3.1 pH Homeostasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
3.2 Protective Cell Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
3.3 Bioenergetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
3.4 Coping Intracellular Alkalinization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
3.5 Production of Extracellular Biomolecules Which Are Operationally Stable
in Alkaline Milieu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
3.6 Adaptation to Low Nutrient Bioavailability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
4 Adaptations of Eukaryotes to High pH Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Abstract A vast array of organisms is known thriving in high pH environments.
The biotechnological, medical, and environmental importance of this remarkable
group of organisms has attracted a great deal of interest among researchers and
industrialists. One of the most intriguing phenomena of alkaliphiles that engrossed
researchers’ attention is their adaptation to high pH and ability to thrive in the
“extreme” condition which is often lethal to other organisms. Studies made in this
line revealed that alkaliphiles deployed a range of adaptive strategies to overcome
the various challenges of life in high pH environments. This chapter highlights some
of the challenges and the most important structural and functional adaptations
that alkaliphiles evolved to circumvent the hurdles and flourish in alkaline habitats.
The fascinating alkaliphiles’ pH homeostasis that effectively maintains a lower
G. Mamo (*)
Indienz AB, Billeberga, Sweden
e-mail: gashaw.mamo1@gmail.com
DOI: 10.1007/10_2019_97
© Springer Nature Switzerland AG 2019
Published online: 5 July 2019
Challenges and Adaptations of Life
in Alkaline Habitats
Gashaw Mamo
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
2 The Grand Challenges to Thrive in Alkaline Habitats from a Neutralophilic
Standpoint . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . 89
3 Adaptation of Alkaliphiles: Circumventing the Challenges of Alkalinity . . . . . . . . . . . . . . . . . 92
3.1 pH Homeostasis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
3.2 Protective Cell Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
3.3 Bioenergetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
3.4 Coping Intracellular Alkalinization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
3.5 Production of Extracellular Biomolecules Which Are Operationally Stable
in Alkaline Milieu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
3.6 Adaptation to Low Nutrient Bioavailability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
4 Adaptations of Eukaryotes to High pH Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Abstract A vast array of organisms is known thriving in high pH environments.
The biotechnological, medical, and environmental importance of this remarkable
group of organisms has attracted a great deal of interest among researchers and
industrialists. One of the most intriguing phenomena of alkaliphiles that engrossed
researchers’ attention is their adaptation to high pH and ability to thrive in the
“extreme” condition which is often lethal to other organisms. Studies made in this
line revealed that alkaliphiles deployed a range of adaptive strategies to overcome
the various challenges of life in high pH environments. This chapter highlights some
of the challenges and the most important structural and functional adaptations
that alkaliphiles evolved to circumvent the hurdles and flourish in alkaline habitats.
The fascinating alkaliphiles’ pH homeostasis that effectively maintains a lower
G. Mamo (*)
Indienz AB, Billeberga, Sweden
e-mail: gashaw.mamo1@gmail.com