Mitigation of soil salinization and alkalization by bacterium-induced inhibition of evaporation and salt crystallization

• Published in: The Science of the total environment 2021-02, Vol.755 (Pt 1), p.142511, Article 142511
• Main Authors: Wang, Ziyan, Tan, Wenjuan, Yang, Dengqin, Zhang, Keqing, Zhao, Liwei, Xie, Zhengguo, Xu, Tao, Zhao, Yuwei, Wang, Xiaonan, Pan, Xiangliang, Zhang, Daoyong
• Format: Article
• Language: English
• Subjects: Bacillus subtilis BSN-1; Bacteria; Ca2; China; Crystallization; Evaporation crystallization; HPO42; Saline soil; Sodium Chloride; Soil
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.142511

Soil salinization and alkalization is one of the most devastating environmental problems, threatening the sustainable development of agriculture. Bio-amelioration using microorganisms such as bacteria is a promising method for the remediation of calcareous sodic and saline-sodic soil due to its high efficiency, low cost and environmental-friendly characteristics. In the present study, a salt resistant bacterium, Bacillus subtilis BSN-1, was isolated from arid region in Xinjiang, China, and its effects on salt crystallization during evaporation crystallization of saline-alkali soil solution were examined. It was found that the fermentation products of B. subtilis BSN-1, such as glutamic acid, significantly lowered the pH of saline soil solution because of the ionization of carboxyl. The complexation between Ca2+ and fermentation products inhibited the precipitation of Ca–P compounds as well, since the binding sites supplied for Ca2+ is one or two orders of magnitude than that for HPO42−. Moreover, the increased content of active phosphate is attributed to the chelation and adsorption exerted through carboxyl and amide bonds. These findings demonstrated that Bacillus subtilis BSN-1 suppressed the crystallization of phosphate and therefor increased the content of active phosphate, which may provide a promising solution for amendment and remediation of saline-alkali soil. [Display omitted] •Bacillus subtilis BSN-1 lowered the pH of soil due to ionization of glutamic acid.•The inoculation of B. subtilis BSN-1 inhibited the precipitation of Ca–P compounds.•Content of active phosphate was increased in the presence of B. subtilis BSN-1.