EC Microbiology

Research Article Volume 21 Issue 6 - 2025

An Assessment of the Physicochemical Properties and Identification of Associated Haloalkaliphilic Bacteria in Buhera Soda Pans, Eastern Zimbabwe

Nyaradzai Moyo1, Thembekile Ncube2 and Ngonidzashe Mangoma1*

1Department of Applied Biology and Biochemistry, National University of Science and Technology, Ascot, Bulawayo, Zimbabwe

2Research and Internationalization Office, National University of Science and Technology, Ascot, Bulawayo, Zimbabwe

*Corresponding Author: Ngonidzashe Mangoma, Department of Applied Biology and Biochemistry, National University of Science and Technology, Ascot, Bulawayo, Zimbabwe.
Received: May 22, 2025; Published:July 01, 2025




Soda pans and lakes are naturally-occurring aquatic environments characterised by stable alkaline pH, moderate to high salinity, high carbonate and sodium ion content. The elevated alkalinity and salinity of soda pans and lakes make them amenable to inhabitation by unique microbiomes dominated by extremophilic microorganisms that thrive under saline and/or alkaline conditions. The extremophilic inhabitants of soda pans and lakes include the salt-loving halophiles, alkali-loving alkaliphiles and dual-extremophilic haloalkaliphiles.

This study sought to determine the physicochemical profile, as well as isolate and characterise haloalkaliphilic bacteria from a previously uncharacterised soda pan located in Buhera, Zimbabwe. Soda pan water and sediment samples were collected and analysed for pH, salinity and carbonate and bicarbonate ion content. Haloalkaliphilic bacteria were isolated from the water and sediment samples using saline-alkaline broth (for enrichment) and agar (for isolation) with pH and salinity set at 10 and 3% NaCl (w/v), respectively, with the cultures being incubated aerobically at 30°C. The isolates were characterised using a range of morphological and biochemical tests. The effect of varying pH and salinity on the growth of the isolates was investigated. The isolates were also screened for their ability to produce extracellular lipase, amylase and protease. For molecular characterisation of the organisms, genomic DNA was extracted, followed by 16S rRNA gene PCR amplification and sequencing. The sequence reads were then used for the taxonomic placement and phylogenetic profiling of the isolates.

Physicochemical analysis indicated that the soda pan was characterised by alkaline pH in the range 9.46 - 10.44, moderate salinity averaging 3.60 g/l, and carbonate and bicarbonate ion content of 3400 mg/l and 1325 mg/l, respectively. Six haloalkaliphilic isolates were obtained, with three being members of the Halomonas genus, one belonging to genus Marinospirillum, and another one to genus Alkalibacterium. One isolate could not be conclusively identified based on its 16S rRNA gene sequence. All isolates appeared to belong to two bacterial phyla, that is Pseudomonadota and Bacillota. The isolates were shown to be capable of producing at least one of the three enzymes; lipase, amylase and protease. All organisms were shown to have alkaline optimum pH for growth, with 5% NaCl appearing to be the most common optimum salinity for most isolates.

These findings lay a strong foundation for the further and more detailed exploration of this promising extreme microbial habitat.

 Keywords: Soda Pans; Haloalkaliphilic Bacteria; Extremophile; Hydrolases

  1. Rampelotto PH. "Extremophiles and extreme environments”. Life 3 (2013): 482-485.
  2. Gupta A., et al. “Microbes and environment”. In: Principles and applications of environmental biotechnology for a sustainable future (2017): 43-84.
  3. Boros E., et al. "Multiple extreme environmental conditions of intermittent soda pans in the Carpathian Basin (Central Europe)”. Limnologica 62 (2017): 38-46.
  4. Horikoshi K. "Alkaliphiles: some applications of their products for biotechnology”. Microbiology and Molecular Biology Reviews4 (1999): 735-750.
  5. Slonczewski Joan L., et al. "Cytoplasmic pH measurement and homeostasis in bacteria and archaea”. Advances in Microbial Physiology 55 (2009): 1-79, 317.
  6. Oren A. "Life in magnesium-and calcium-rich hypersaline environments: salt stress by chaotropic ions”. Polyextremophiles: life under multiple forms of stress. Dordrecht: Springer Netherlands (2013): 215-232.
  7. Boros E and Kolpakova M. "A review of the defining chemical properties of soda lakes and pans: An assessment on a large geographic scale of Eurasian inland saline surface waters”. PLoS One8 (2018): e0202205.
  8. Banciu HL and Muntyan MS. "Adaptive strategies in the double-extremophilic prokaryotes inhabiting soda lakes”. Current Opinion in Microbiology 25 (2015): 73-79.
  9. Baati H., et al. "Isolation and characterization of moderately halophilic bacteria from Tunisian solar saltern”. Current Microbiology3 (2010): 157-161.
  10. Kumar S., et al. "Screening and isolation of halophilic bacteria producing industrially important enzymes”. Brazilian Journal of Microbiology4 (2012): 1595-1603.
  11. Musikoyo EO., et al. "Bacteria with industrial potential from Lake Nakuru, Kenya”. African Journal of Aquatic Science2 (2015): 205-213.
  12. Nyakeri E., et al. "Isolation and characterization of enzyme producing bacteria from Lake Magadi, an extreme soda lake in Kenya”. Journal of Microbiology and Experimentation 2 (2018): 57-68.
  13. Parihar J and Bagaria A. "The extremes of life and Extremozymes: diversity and perspectives”. Acta Scientific Microbiology1 (2019): 107-119.
  14. Indian Institute of Technology Kanpur. Methods of Sampling and Test (Physical and Chemical) for Water and Wastewater, Part 23 - Alkalinity: Amendment Number 2. India: Kanpur (2006).
  15. Edwards U., et al. "Isolation and direct complete nucleotide determination of entire genes. Characterization of a gene coding for 16S ribosomal RNA”. Nucleic Acids Research19 (1989): 7843-7853.
  16. Tamura K., et al. "MEGA11: molecular evolutionary genetics analysis version 11”. Molecular Biology and Evolution 7 (2021): 3022-3027.
  17. https://blast.ncbi.nlm.nih.gov
  18. Tamura K and Nei M. "Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees”. Molecular Biology and Evolution 3 (1993): 512-526.
  19. USGS: Saline water and salinity (2024).
  20. Tarawneh KA., et al. "Isolation and characterization of halophilic bacteria from the dead sea coast, Jordan”. Advances in Environmental Biology 2 (2008): 63-69.
  21. Akhwale JK., et al. "Isolation, characterization and analysis of bacteriophages from the haloalkaline lake Elmenteita, Kenya”. PloS one4 (2019): e0215734.
  22. Felföldi T. "Microbial communities of soda lakes and pans in the Carpathian Basin: a review”. Biologia Futura4 (2020): 393-404.
  23. Sorokin DY., et al. "Natronosporangium hydrolyticum nov., sp. nov., a haloalkaliphilic polyhydrolytic actinobacterium from a soda solonchak soil in Central Asia”. Systematic and Applied Microbiology 45.3 (2022): 126307.
  24. Mangoma N., et al. "Metagenomic insights into the microbial community of the Buhera soda pans, Zimbabwe”. BMC Microbiology1 (2024): 510.
  25. Mangoma N., et al. "Exploring the diversity and phenotypic properties of culturable haloalkaliphilic bacteria from soda pans in Buhera, Zimbabwe”. Academia Biology2 (2025).
  26. Ye J-W and Chen GQ. "Halomonas as a chassis”. Essays in Biochemistry2 (2021): 393-403.
  27. Yin Y-L., et al. "Halomonas salinarum nov., a moderately halophilic bacterium isolated from saline soil in Yingkou, China”. Archives of Microbiology 204.8 (2022): 466.
  28. Satomi M., et al. "Marinospirillum nov., with descriptions of Marinospirillum megaterium sp. nov., isolated from kusaya gravy, and transfer of Oceanospirillum minutulum to Marinospirillum minutulum comb. nov”. (1998): 1341-1348.
  29. Yuan F., et al. "The richness and diversity of catalases in bacteria”. Frontiers in Microbiology 12 (2021): 645477.
  30. Grant WD. "Alkaline environments and biodiversity”. Extremophiles 3 (2009): 21.
  31. Duckworth AW., et al. "Phylogenetic diversity of soda lake alkaliphiles”. FEMS Microbiology Ecology3 (1996): 181-191.
  32. El Hidri D., et al. "Cultivation‐dependant assessment, diversity, and ecology of haloalkaliphilic bacteria in arid saline systems of southern Tunisia”. BioMed Research International (2013): 648141.
  33. Melton ED., et al. "Complete genome sequence of Desulfurivibrio alkaliphilus strain AHT2 T, a haloalkaliphilic sulfidogen from Egyptian hypersaline alkaline lakes”. Standards in Genomic Sciences1 (2016): 67.
  34. Kulkarni S., et al. "Alkaliphiles: diversity and bioprospection”. Microbial diversity in the genomic era. Academic Press (2019): 239-263.
  35. Deshmukh KB., et al. "Bacterial diversity of Lonar soda lake of India”. Indian Journal of Microbiology1 (2011): 107-111.
  36. Mwirichia R., et al. "Isolation and characterisation of bacteria from the haloalkaline Lake Elmenteita, Kenya”. Extremophiles 4 (2010): 339-348.
  37. Mesbah NM and Wiegel J. "Life under multiple extreme conditions: diversity and physiology of the halophilic alkalithermophiles”. Applied and Environmental Microbiology12 (2012): 4074-4082.
  38. Ma Y., et al. "Bacterial diversity of the Inner Mongolian Baer Soda Lake as revealed by 16S rRNA gene sequence analyses”. Extremophiles 1 (2004): 45-51.
  39. https://bacterio.net
  40. Yumoto I., et al. "Alkalibacterium indicireducens nov., an obligate alkaliphile that reduces indigo dye”. International Journal of Systematic and Evolutionary Microbiology 58.4 (2008): 901-905.

Ngonidzashe Mangoma., et al. “An Assessment of the Physicochemical Properties and Identification of Associated Haloalkaliphilic Bacteria in Buhera Soda Pans, Eastern Zimbabwe”. EC Microbiology  21.7 (2025): 01-11.

ECronicon Journal

Our Services

Quick Links

Information

Creative Commons LicenseOpen Access by ECronicon is licensed under a Creative Commons Attribution 4.0 International License
Based on a work at www.ecronicon.net