Effect of lignin carbon material on phosphorus solubilisation performance of Bacillus megaterium

Secondary salinisation significantly compromises soil quality because of the over-application of chemical fertilisers. The combined application of biochar and microorganisms enhanced soil physicochemical properties and improved soil remediation efficiency. However, different types of biochar had varying effects on microbial growth and reproduction. A phosphate-solubilising bacterial agent (BM-LPC) was obtained by low-temperature carbonisation/activation lignin-based porous carbon (LPC) in situ culture/adsorption Bacillus megaterium (BM). The maximum soluble phosphorus capacity of BM-LPC was 744.29 mg/L when 1 % LPC was added. This was a 22 % increase compared with BM alone. The maximum adsorption of BM by LPC was 3.66 × 10⁹ colony-forming units (CFU)/g. At 150 days, the viable bacterial count of BM-LPC was 2.09 × 10⁹ CFU/g. The abundances of -OH, -COOH, -NH₂, and CO groups on the surface of LPC provided a stable environment for BM, which in turn, enhanced the solubilisation of phosphorus and extended the viability of BM. The findings of this study can help increase the added value of industrial lignin and provide a theoretical basis for soil remediation research.