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Alkaliphilic Bacteria and Thermophilic Actinomycetes as New Sources of Antimicrobial Compounds
Published in Devarajan Thangadurai, Jeyabalan Sangeetha, Industrial Biotechnology, 2017
Suchitra B. Borgave, Meghana S. Kulkarni, Pradnya P. Kanekar, Dattatraya G. Naik
One of the key features on alkaliphily is associated with the cell surface, which discriminates and maintains the intracellular neutral environment separate from the extracellular alkaline environment. In addition, surface located and excreted enzymes resistant to the effects of extreme pH, the pH gradient reversed to carry out ATP synthesis. Alkaliphilic bacteria compensate the reversal of the pH gradient by having a high membrane potential or by coupling Na+ expulsion to electron transport for pH homeostasis and energy transduction. Alkaliphilic bacteria are considered for production of enzymes such as protese, amylase, lipase, xylanase, catalase, pectinase, pullulanase, chitinase which have potential applications in various fields of biotechnology. Alkaliphiles also produce polyhydroxyalkanoates (PHAs) which are bacterial polyesters having biodegradable nature and properties close to plastics from petrochemical routes. Some alkaliphilic bacteria produce exopolysaccharides which find a wide range of applications in food, pharmaceutical, petroleum and other industries (Sutherland, 1990).
Application of Extremophiles in the Area of Bioenergy
Published in Pratibha Dheeran, Sachin Kumar, Extremophiles, 2022
Alkaliphile are the microorganisms which grow and function very efficiently at basic environmental condition with pH 9 or above but their growth cease at neutral pH. Alkaliphiles generally include prokaryotes, eukaryotes, and archaea. Alkaliphiles are generally found in a normal environmental condition such as garden soil, high pH hotsprings, shallow hydrothermal system, and sewage. Unlike acidophiles, the cellular activity of alkaliphiles involves H+ influx to drive ATP synthesis. Alkaliphiles secrete alkaline cellulases and/or alkaline proteases which has applications in biological detergent industries.
Seasonal Dynamics of Bacterial and Fungal Lineages in Extreme Environments
Published in Suhaib A. Bandh, Javid A. Parray, Nowsheen Shameem, Climate Change and Microbial Diversity, 2023
Nafeesa Farooq Khan, Uzma Zehra, Zafar A. Reshi, Manzoor Ahmad Shah, Tawseef Rehman Baba
In addition to other adaptations similar halophiles, alkaliphiles show high pH adaptability (Kanekar et al., 2012; Pikuta et al., 2008; Michels and Bakker, 1985). Since they thrive in a low H+ environment, alkaliphiles change the cell’s biochemical processes and influence the cell membrane’s morphological configurations against the external environment’s strong pH (Dhakar and Pandey, 2016) to combat the imbalance of H+ ions (Elleuche et al., 2014). Also, significantly larger Na+ extrusion produces a higher salt generated power which has been important to most of the bacterial ATP synthases being energized (Dhakar and Pandey, 2016; Tiquia-Arashiro et al., 2016). Perhaps the most prevalent adjustment is exerted in using antiporters (sodium/hydrogen and potassium/hydrogen type) driving H+ relocation inside and outside the cell (Dhakar and Pandey, 2016), for example, Natranaerobius thermophilus and Desulfovibrio vulgaris are typical anaerobes that use Na+/H+ antiporters, whereas Bacillus psuedofirmus and also Synchococcus elongatus altogether represent Na+(K+)/ Na+H+ channel transport (Krulwich et al., 2011; Mesbah et al., 2009, 2011). They further utilize teichurono/(ic) or polyglutamic acids (Aono et al., 1992, 1993), from acidic secondary walls, to attract H+ and keep away OH−, required to drive ATP synthesis. Thus alkaliphiles are able to hydrolyze amino acids, retain meager content of alkali amino acids, enriching negatively charged cell membrane constituents, and have greater unsaturated fats and channel proteins in membrane as possible methods to counteract raised pH (Preiss et al., 2015; Slonczewski et al., 2009; Mamo, 2019; DeCaen et al., 2014).
A systematic review on MICP technique for developing sustainability in concrete
Published in European Journal of Environmental and Civil Engineering, 2023
Santosh Ashok Kadapure, Umesh B. Deshannavar, Basavaraj G. Katageri, Poonam S. Kadapure
The pH of concrete is around 12–13. In these alkaline conditions, the selected bacteria should survive or undergo in dormant stage. The bacteria which can undergo in dormant stage or survive at higher pH are called alkaliphiles. Extreme alkaliphiles adapts to harsh environment through the evolutionary modification of lipid, protein structure and mechanisms to maintain the proton motive force in an alkaline environment. Sporosarcina pasteurii the most common bacteria used in MICP technique has optimum pH of 8 and calcite formation was found to decrease in the pH range of 8.7 to 9.5. Above this pH, activity of the enzyme is found to decrease which retards biomineralization process and low quantity of calcite formation may take place. At lower pH, carbonate gets dissolved with less amount of calcite precipitation (Wang et al., 2016).
Removal of alkalinity and metal toxicity from incinerated biomedical waste ash by using Bacillus halodurans
Published in Bioremediation Journal, 2022
Harsimranpreet Kaur, Rafat Siddique, Anita Rajor
Alkaliphilic microorganisms can play a crucial role because of its biotechnological applications due to enzymes viz. proteases, cellulases, xylanases that are stable at high pH (>9.5) and temperature (>50 °C) (Kumar et al. 2014; Gupta et al. 2008; Engle et al. 1995). The alkaliphiles microorganisms have great potential in bioremediation and dealing with toxicity. The enzymes present in the alkaliphiles enable them to resist the alkaline environment to biodegrade certain xenobiotics. The cell surface of alkaliphile can maintain the intracellular pH values near neutral in the alkaline environment of pH 10–13. The presence of Na + ions in the growth medium plays a pivotal role in the adaptation of alkaliphilic Bacillus species at high pH values. This method is called bioremediation, in which the bacteria stabilizes the content of the toxic metal through its natural metabolic process.
A Review on Bioflotation of Coal and Minerals: Classification, Mechanisms, Challenges, and Future Perspectives
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Kaveh Asgari, Qingqing Huang, Hamid Khoshdast, Ahmad Hassanzadeh
Solution pH is one of the most critical and decisive parameters of the flotation process. This factor has a crucial effect not only on the growth and adaptation of the bacterial population but also on the efficiency of the bioflotation process. Table 5 shows a summary of conducted investigations on the effects of pH on the bioflotation process. Bacteria typically live and grow over a wide range of pH based on their nature and type and are defined as acidophiles, neutrophils, and alkaliphiles (Qusheng and Matthew 2018). Alkaliphiles are organisms that grow optimally between a pH of 8 and 10.5, neutrophils grow best at neutral pH close to 7.0 and acidophiles grow optimally at a low pH range of 1 to 3.