An Exploration of Seaweed Polysaccharides Stimulating Denitrifying Bacteria for Safer Nitrate Removal

• Published in: Molecules (Basel, Switzerland) Vol. 26; no. 11; p. 3390
• Main Authors: Zhang, Hui, Song, Lin, Chen, Xiaolin, Li, Pengcheng
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 03.06.2021; MDPI
• Subjects: Accumulation; Agriculture; Algae; Alginic acid; Bacillus subtilis; Bacteria; Biomass; Bioremediation; Carrageenan; Denitrification; Denitrifying bacteria; Fertilizers; growth promotion; Growth rate; Microorganisms; Molecular weight; Nitrate removal; Nitrates; Nitrogen; Nitrogen dioxide; Nitrogen removal; Nutrient removal; Polysaccharides; Pseudomonas putida; Saccharides; Salinization; seaweed polysaccharides; Seaweeds; Sodium alginate; Soil microorganisms; Soil remediation; Soil salinity; Sustainability; Sustainable agriculture; Toxicity; Water pollution treatment
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26113390

Excessive use of nitrogen fertilizer in intensively managed agriculture has resulted in abundant accumulation of nitrate in soil, which limits agriculture sustainability. How to reduce nitrate content is the key to alleviate secondary soil salinization. However, the microorganisms used in soil remediation cause some problems such as weak efficiency and short survival time. In this study, seaweed polysaccharides were used as stimulant to promote the rapid growth and safer nitrate removal of denitrifying bacteria. Firstly, the growth rate and NO3−-N removal capacity of three kinds of denitrifying bacteria, Bacillus subtilis (BS), Pseudomonas stutzeri (PS) and Pseudomonas putida (PP), were compared. The results showed that Bacillus subtilis (BS) had a faster growth rate and stronger nitrate removal ability. We then studied the effects of Enteromorpha linza polysaccharides (EP), carrageenan (CA), and sodium alginate (AL) on growth and denitrification performance of Bacillus subtilis (BS). The results showed that seaweed polysaccharides obviously promoted the growth of Bacillus subtilis (BS), and accelerated the reduction of NO3−-N. More importantly, the increased NH4+-N content could avoid excessive loss of nitrogen, and less NO2−-N accumulation could avoid toxic effects on plants. This new strategy of using denitrifying bacteria for safely remediating secondary soil salinization has a great significance.