Aspergillus niger Enhances Organic and Inorganic Phosphorus Release from Wheat Straw by Secretion of Degrading Enzymes and Oxalic Acid

Abstract

To explore the mechanisms of crop straw degradation and phosphorus (P) release by phosphate-solubilizing fungi (PSF), a typical PSF Aspergillus niger (A. niger, ANG) was investigated for the degradation of wheat straw (WST) in this work. The results revealed that A. niger significantly increased wheat straw degradation (30%) compared with no A. niger treatment (7.7%). Meanwhile, more than 92% of total P was released from WST by A. niger, much higher than from WST treatment (69.5%). Although the ratios of inorganic P release between WST and WST + ANG treatments were similar (17.6 vs 19.7%), a significant difference occurred between their release of organic P, i.e., WST (51.9%) vs WST + ANG (72.5%). The high enzyme activity of β-1,4glucanase and β-glucosidase produced by A. niger contributed to the wheat straw degradation and organic P release compared with no A. niger treatment. Oxalic acid secreted by A. niger dominated the release of inorganic P from WST. Our findings suggested that A. niger is an efficient microbial agent for crop straw degradation and P release, which could be a candidate in the pathway of straw return.

Determination of organic acids for predicting sourness intensity of tea beverage by liquid chromatography–tandem mass spectrometry and chemometrics methods

“…Post‐fermented Pu‐erh tea is a microbially‐fermented tea, of which Aspergillus niger is the dominant fungi in the fermentation. Wang and coworkers demonstrated that oxalic acid was significantly secreted by Aspergillus niger in crop straw degradation [32]. DeBolt et al.…”

“…Post-fermented Pu-erh tea is a microbially-fermented tea, of which Aspergillus niger is the dominant fungi in the fermentation. Wang and coworkers demonstrated that oxalic acid was significantly secreted by Aspergillus niger in crop straw degradation [32]. DeBolt et al suggested that TA biosynthesis begins with L-ascorbic acid, and in an indirect pathway, OxA and L-threonate are considered intermediates for the generation of TA [33].…”

Probiotic Potential, Antibacterial and Antioxidant Capacity of Aspergillus luchuensis YZ-1 Isolated from Liubao Tea

“…The pH of the fermentation supernatant decreased sharply within 48 h, probably due to the rapid production and accumulation of organic acids during this period [12,37], while the pH decreased slowly after 48 h probably related to the slowed growth rate of the fungus at this time. After 72 h, the pH increased slowly again, which may be related to the autolysis of the fungus.…”

Organic amendments with high proportion of heterocyclic compounds promote soil microbiome shift and microbial use efficiency of straw-C

“…Fungi can degrade complex organic macromolecules into numerous small molecules using secretory extracellular enzymes such as cellulase and laccase ( Clocchiatti et al, 2020 ). Except for the stronger ability of fungi to secrete extracellular enzymes, the large amounts of organic acids secreted by fungi also degrade straw ( Wang et al, 2022 ). The simpler organic compounds are then used by bacteria for growth, contributing to the microbial CUE ( Zhao et al, 2019 ).…”