Work

Unlocking bioenergy potential in heavy metal polluted soils: synergistic advanced solid-state fermentation and combustion for valorization of sweet sorghum

Year: 2025

Type: article

Abstract: BACKGROUND: A novel co-disposal strategy integrating advanced solid-state fermentation (ASSF) and combustion was proposed to address the dual challenges of safe utilization and value-added conversion of heavy metal-enriched sweet sorghum (Sorghum bicolor (L.) Moench) biomass from phytoremediation. RESULTS: Controlled field experiments demonstrated that Cd, Pb, and Cu concentrations in sweet sorghum organs increased significantly with elevated soil metal levels, following distinct accumulation patterns: roots > stems > leaves > grains for Cd and Cu, versus roots > leaves > stems > grains for Pb. Despite high metal loads in stalks (up to 7.00 ± 0.85 mg/kg Cd, 19.51 ± 2.1 mg/kg Pb, and 44.06 ± 3.4 mg/kg Cu), ASSF performance was not significantly inhibited, achieving a sugar utilization rate of 96.69 ± 0.81% and an ethanol conversion efficiency of 91.8 ± 1.2%. Subsequent combustion of fermentation residues at optimized condition (900 °C) effectively concentrated heavy metals in specific byproducts: Cd and Pb were primarily enriched in fly ash, with concentrations of 63.3 ± 18.09 mg/kg and 799.84 ± 97.25 mg/kg, respectively, whereas Cu accumulated in bottom ash at a concentration of 238.60 ± 67.13 mg/kg. This partitioning enables targeted metals recovery from fly ash while permitting the safe reuse of bottom ash as a soil amendment to improve soil environment. CONCLUSIONS: Our findings provide a closed-loop solution linking phytoremediation, bioenergy production, and resource recovery and utilization, offering both technical and economic viability for sustainable management of heavy metal-contaminated farmland.

Source: BMC Plant Biology

DOI: 10.1186/s12870-025-08005-4

Authors: Z. C. Xue, J. Liu, C. M. Zhang, P. Lv, Z. Y. Jiao, S. Z. Li

Institutions: Hebei Minzu Normal University, Xuzhou Vocational College of Bioengineering, Hebei Academy of Agriculture and Forestry Sciences, Tsinghua University

Language: English

Topic: Biofuel production and bioconversion

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Affordable and clean energy, Life on land, Zero hunger

Open Access status: gold

Estimated APC paid: $3,090