Diversity of cultivated aerobic poly-hydrolytic bacteria in saline alkaline soils

Abstract

Alkaline saline soils, known also as “soda solonchaks”, represent a natural soda habitat which differs from soda lake sediments by higher aeration and lower humidity. The microbiology of soda soils, in contrast to the more intensively studied soda lakes, remains poorly explored. In this work we investigate the diversity of culturable aerobic haloalkalitolerant bacteria with various hydrolytic activities from soda soils at different locations in Central Asia, Africa, and North America. In total, 179 pure cultures were obtained by using media with various polymers at pH 10 and 0.6 M total Na+. According to the 16S rRNA gene sequence analysis, most of the isolates belonged to Firmicutes and Actinobacteria. Most isolates possessed multiple hydrolytic activities, including endoglucanase, xylanase, amylase and protease. The pH profiling of selected representatives of actinobacteria and endospore-forming bacteria showed, that the former were facultative alkaliphiles, while the latter were mostly obligate alkaliphiles. The hydrolases of selected representatives from both groups were active at a broad pH range from six to 11. Overall, this work demonstrates the presence of a rich hydrolytic bacterial community in soda soils which might be explored further for production of haloalkalistable hydrolases.

Wenzhouxiangella Strain AB-CW3, a Proteolytic Bacterium From Hypersaline Soda Lakes That Preys on Cells of Gram-Positive Bacteria

“…In addition to S. aureus, another two Gram-positive organisms were tested as substrate for AB-CW3 -Micrococcus luteus (DSM 20030) and the haloalkaliphilic actinobacterium Isoptericola sp. DS111 (Sorokin et al, 2017b). Isoptericola grows as a suspension of individual cells.…”

“…To investigate whether it was also able to grow with other Gram-positive bacteria, AB-CW3 was incubated with cells of Micrococcus and Isoptericola. The latter is a halo-alkaliphilic Actinobacterium isolated from a saline soda soil in the same area as AB-CW3 (Sorokin et al, 2017b). Both Micrococcus and Isoptericola supported growth of AB-CW3.…”

The Effects of Saline Stress on the Growth of Two Shrub Species in the Qaidam Basin of Northwestern China

“…Several studies have suggested two main reasons for the decrease in net photosynthetic rate under saline-alkaline stress, namely stomatal restriction caused by partial closure of stomata and decreased cell viability [34][35][36]. The decrease in intercellular carbon dioxide concentration and stomatal conductance were the main reasons for the decreased photosynthesis rates [37].…”