Some ecological and physiological studies on bacteria isolated from salt‐affected soils of Egypt

Abstract

Members of Bacillaceae, Rhizobiaceae, actinomycetes and others were isolated from cultivated and non-cultivated saline soils. The high population of bacteria and actinomycetes were almost coincided with the relatively high levels of organic matter whatever the degree of soil salinity. Bacillus stearothermophilus and B. subtilis were more frequently isolated than other Bacillus species. Most of Rhizobium isolates were salt tolerant being able to grow in media containing 3% and 6% NaCl. The abilities of different bacterial isolates to attack citrus pectin, soluble and insoluble forms of cellulose were also tested.

Studies on Non-Symbiotic Diazotrophic Bacterial Populations of Coastal Arable Saline Soils of India

“…These variations seemed to be related to the physicochemical characteristics of soils, the inherent type and diversity of microorganisms occurring in these soils [18,19,20].It was interesting to note that inspite of rise in salinity, even up to the levels of 26 and 28 dSm -1 in S3 and S4 soils, respectively, during the summer season, the soils supported considerable diazotrophic populations. The total count of bacteria is usually negatively correlated with the total soluble salts of saline soils [21], but positively correlated with organic carbon contents [21,22]. However, these soils might have their own bacterial communities, which have adapted to saline environments.…”

Isolation and Characterization of Halophilic Bacteria from Sundarban Soil

“…Halophilic and halo tolerant microorganisms are able to thrive and grow in saline and hypersaline environments [2]. These microorganisms are being the object of basic studies in relation to the origin of life in our planet and the molecular mechanisms of adaptation to saline and hyper-saline conditions.…”

Osmotolerant Microbial Resources of Saline Ecologies of India: Dynamics and Potential

“…oxidized sulphur which tolerated ≥ 10 % or more NaCl (Mishra et al 2009(Mishra et al , 2011(Mishra et al , 2012a (Mishra et al 2009(Mishra et al , 2011(Mishra et al , 2012aThatoi et al 2012). Bhitarkanika contains large amount of C and other nutrients which support different microbial communities responsible for major nutrient transformations (Holguin et al 2001;Mishra et al 2009;, 2012a and supported report of Zahran et al (1992) that the Gram-positive bacteria are well represented in the saline habitat and the Bacillus sp. and Micrococcus sp.…”

“…Usually, the natural saline environments (4-30 % NaCl level) are widely distributed in arid and semiarid regions, contain Na + (predominant), K + , Mg 2+ and Ca 2+ cations; higher free chlorides (mainly), few sulfates, nitrates, carbonates and bicarbonate anions and electrical conductivity (EC) > 4 dS/m, exchangeable sodium (%) (ES) > 15 and pH 8.5-10.7, but poor in soil structure, nitrogen, phosphorus and zinc contents (Zahran 1997;Zahran et al 1992). The pH of hypersaline ecosystems is usually < 8.5 as the soluble salts are mainly neutral and exchangeable sodium is < 15 %, presence of variable amounts of ammonia and nitrate, and the divalent cations like Mg 2+ and Ca 2+ concentrations are either low or absent (Zahran 1997;Zahran et al 1992). In limited organic matter containing hypersaline soil, sulfate acts as electron acceptor during anaerobic mineralization which prevails in the organic poor Indian saline soils.…”