PROBLEMS OF NON-STERILE CULTIVATION OF EXTREMELY HALOPHILIC MICROORGANISMS

• Published in: International Multidisciplinary Scientific GeoConference : SGEM Vol. 20; no. 6.2; pp. 105 - 112
• Main Authors: Kalenov, Sergei V, Belov, Alexey A, Lyapkin, Evgeniy I, Sachavskii, Aleksandr A, Panfilov, Victor I
• Format: Conference Proceeding
• Language: English
• Published: Sofia Surveying Geology & Mining Ecology Management (SGEM) 01.01.2020
• Subjects: Archaea; Bacteria; Biological activity; Biotechnology; Carotenoids; Charcoal; Contaminants; Contamination; Cultivation; Density; Economics; Experiments; Halobacterium salinarum; Halomonas; Halophiles; Halophilic archaea; Halophilic bacteria; Laboratories; Microflora; Microorganisms; Photosystem; Polyhydroxyalkanoates; Polysaccharides; Saccharides; Salinity tolerance; Salts; Sterility; Viruses
• ISSN: 1314-2704
• DOI: 10.5593/sgem2020V/6.2/s08.14

Modern industrial biotechnology considers extremophilic microorganisms and, in particular, extreme halophiles as promising producers for the bioeconomy of the future. Extremely halophilic bacteria and archaea can be used for the production of carotenoids, polyhydroxyalkanoates, polysaccharides, osmoprotectors, thermostable enzymes, photosystem proteins, and can also be sources of unique biologically active substances for medical purposes. The implementation of large-scale industrial processes with minimal requirements for sterility conditions is a possible advantage of using extremely halophilic producers from an economic point of view. However, the practice of long-term continuous and high-density cultivation of extreme halophiles in laboratory conditions has revealed the possibility of contamination and intensive development of extraneous microflora, as well as viral infection. The sources of contamination in these cases were the non-sterile salts and air used. In this work, in non-sterile experiments under various cultivation regimes with the extremely halophilic archaea Halobacterium salinarum and the highly halotolerant bacterium Halomonas utahensis, the contaminating microflora, which in some cases replaced the original culture, was isolated and characterized. The influence of viruses on the processes of high-density cultivation was also studied. The influence of various factors on the development of contaminants, which belonged to the genera Natronococcus, Alkalibacillus, Halomonas, Chromohalobacter, Lysinibacillus and Bacillus, was established. The latter two bacteria, not having a high halotolerance, successfully multiplied in model experiments and to one degree or another suppressed the growth of Halobacterium salinarum or Halomonas utahensis during coculture. On the basis of the studies carried out, approaches are proposed that reduce the negative effects of contamination during non-sterile cultivation of extreme halophiles.