Fungus and bacteria turn factory waste into plant food
Meng L, Xiao D, Liu X, Cao Y, Lian B
Soil Health
Fertilizer factories produce mountains of phosphogypsum waste every year, and this microbe-driven process could turn that waste into something that helps salty, marginal soils grow plants instead of sitting in toxic stockpiles.
Phosphogypsum is a leftover byproduct from making fertilizer, and there's a huge pile of it worldwide with nowhere useful to go. Researchers found that a mold called Aspergillus niger and a soil bacterium can work together in stages, first turning the gypsum's calcium into oxalate crystals, then converting those into calcite, essentially recycling waste rock into soil-friendly minerals. When they tested the treated gypsum in pots with a salt-tolerant plant, the seedlings grew nearly three times taller and had thicker stems than plants in untreated soil.
Key Findings
Oxalic acid converted phosphogypsum's calcium sulfate into whewellite, while Aspergillus niger fungus dropped culture pH from 5.12 to 2.82 over 8 days while producing whewellite and weddellite crystals
The bacterium Azospirillum brasilense OX-1 further converted the calcium oxalate crystals into calcite, completing a stepwise biotransformation of the waste mineral
Combined phosphogypsum and OX-1 treatment in a 45-day pot trial produced seedlings averaging 11.03 mm tall with 0.81 mm stem diameter, versus 4.67 mm and 0.32 mm in untreated controls
chevron_right Technical Summary
Scientists turned industrial waste gypsum into a plant-friendly soil amendment using fungi and bacteria, and in pot trials it more than doubled seedling height and stem thickness compared to untreated soil.
Abstract Preview
Original paper
Biotransformation of phosphogypsum and its potential for soil-based applications: a preliminary study.
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 ...
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