Serous cystadenofibroma of the fallopian tube: case report and literature review.

UNLABELLED: Promoting the resource utilization of phosphogypsum (PG) is an urgent challenge, and its potential use as a soil amendment has attracted increasing attention. In this study, representative organic acids, the oxalate-producing fungus Aspergillus niger, and the oxalate-degrading bacterium Azospirillum brasilense OX-1 were used, together with a 45-day pot experiment with Suaeda salsa, to investigate the mineral transformation of PG and its potential for soil-based applications. Among the three organic acids tested under identical conditions, only oxalic acid induced the transformation of CaSO4·2H2O in PG into whewellite. During A. niger cultivation, the pH decreased from 5.12 on day 0 to 2.82 on day 8, accompanied by a progressive decrease in the PG mineral phase and the formation of whewellite and weddellite. Calcium oxalate generated from PG through either chemical oxalic acid treatment or A. niger-mediated transformation was further converted to calcite by OX-1. In the pot experiment, the combined PG and OX-1 treatment resulted in the highest mean plant height (11.03 ± 0.67 cm) and stem diameter (0.81 ± 0.07 mm), compared with 4.67 ± 0.40 cm and 0.32 ± 0.19 mm, respectively, in the control. The combined application of PG and OX-1 also significantly altered soil pH, available phosphorus, and other physicochemical properties. These findings provide experimental evidence for the stepwise biological transformation of PG and indicate its potential value as a soil amendment. Further studies are needed to determine whether these transformation processes can occur sequentially in the rhizosphere and to evaluate their long-term environmental effects.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s13205-026-05064-8.