title: Production of a water-soluble fertilizer containing amino acids by solid-state fermentation of soybean meal and evaluation of its efficacy on the rapeseed growth.
abstract: Soybean meal is a by-product of soybean oil extraction and contains approximately 44% protein. We performed solid-state fermentation by using Bacillus subtilis strain N-2 to produce a water-soluble fertilizer containing amino acids. Strain N-2 produced a high yield of protease, which transformed the proteins in soybean meal into peptide and free amino acids that were dissolved in the fermentation products. Based on the Plackett-Burman design, the initial pH of the fermentation substrate, number of days of fermentation, and the ratio of liquid to soybean meal exhibited significant effects on the recovery of proteins in the resulting water-soluble solution. According to the predicted results of the central composite design, the highest recovery of soluble proteins (99.072%) was achieved at the optimum conditions. Under these conditions, the resulting solution contained 50.42% small peptides and 7.9% poly-γ-glutamic acid (γ-PGA). The water-soluble fertilizer robustly increased the activity of the rapeseed root system, chlorophyll content, leaf area, shoot dry weight, root length, and root weight at a concentration of 0.25% (w/v). This methodology offers a value-added use of soybean meal.
authors: College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
authors: Jianlei
authors: J
authors: Wang
authors: College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
authors: Zhemin
authors: Z
authors: Liu
authors: College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
authors: Yue
authors: Y
authors: Wang
authors: College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
authors: Wen
authors: W
authors: Cheng
authors: College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao 266003, China. Electronic address: mousun@ouc.edu.cn.
authors: Haijin
authors: H
authors: Mou
mesh_terms: D000383:Agriculture; D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D000704:Analysis of Variance; D029741:Brassica rapa / Q000187:drug effects / Q000254:growth & development*; D005285:Fermentation; D005308:Fertilizers; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D012107:Research Design; D013025:Glycine max / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D005308:Fertilizers
keywords: Bacillus subtilis; Protease; Solid-state fermentation; Soybean meal; Water-soluble fertilizer