Caixia Jiang, Handong Liu, Xiaolan Liu, Yue Li, Juntong Wang, Xiqun Zheng
Soil salinization poses a key challenge to global agriculture, and there is an urgent need for cost-effective amelioration measures. Microbial fermentation-derived proteases were employed to hydrolyze corn proteins, enriching the polypeptide fractions and enhancing their efficacy as biostimulants. This approach effectively promoted soybean seedling growth and improved tolerance to abiotic stresses. Results revealed that, compared with corn steep liquor, the contents of organic matter, small peptides, and amino acid nitrogen in fermented corn steep liquor increased significantly. Specifically, the proportion of protein components with a molecular weight < 1 kDa rose from 46.84 % to 62.34 %. After application, the phenotypic growth of soybean seedlings was significant, and the leaves' antioxidant and nitrogen metabolism-related enzyme activities were enhanced. The nutrient content and the abundance of beneficial microbial communities in the rhizosphere soil increased, with some bacteria exhibiting greater dominance in carbon and nitrogen cycling and energy metabolism. This study innovated a new pattern of resource utilization of corn processing by-products, aiming to promote synergistic greening of agriculture and the corn processing industry. • Novel fermentation technology was developed for corn steep liquor fermentate (CSLF). • The peptide components enriched in CSLF enhance its efficacy as a biostimulant. • CSLF stimulates plants' antioxidant defense mechanism to boost stress resistance. • CSLF can promote the growth of soybean seedlings in soda saline-alkali soil. • CSLF altered the composition of rhizosphere soil microbial community.