Malic acid soil enrichment to enhance microbial biofilm-mediated carbon sequestration

Overview

This research explores a novel strategy for enhancing soil carbon sequestration by enriching soil with malic acid (MA), a natural compound found in plant seed and root exudates. The central hypothesis is that MA enrichment increases biofilm formation among beneficial soil microbes, which in turn enhances the ability of plants to assimilate and sequester atmospheric carbon. Preliminary work has demonstrated that MA at 0.5% concentration increases biofilm formation in Bacillus amyloliquefaciens ALB629, a beneficial bacterium shown to improve carbon sequestration in common bean plants. The research also investigates whether elevated atmospheric CO2 amplifies this effect, offering a potential dual-benefit approach for sustainable agriculture and climate change mitigation.

Technical specifications

Research approach:

• Common bean plants (n=12 per treatment) grown in 1L pots under four conditions: control soil, soil with 0.5% malic acid, soil under elevated CO2 (1200 ppm), and soil with 0.5% malic acid under elevated CO2 (1200 ppm)
• Growth chambers equipped with a LI-830 CO2 Gas Analyzer system to maintain precise atmospheric CO2 levels
• Infrared gas analysis (IRGA) to measure carbon assimilation weekly, beginning at the V3 phenological stage
• Rhizosphere microbiome profiling using 16S and ITS primers for bacterial and fungal community characterization
• Total soil biofilm quantification via glass slide technique

Key scientific basis:

• Plants recruit beneficial microbes through root and seed exudates
• Certain microbial taxa produce biofilms that improve soil fitness and plant carbon uptake
• Malic acid acts as a targeted soil additive to stimulate biofilm-producing beneficial microbes
• Biofilm-enhanced microbes may thrive better when reintroduced to agricultural environments

Technology readiness level

This research is at an early experimental stage (TRL 2-3), building on validated preliminary findings that MA enrichment increases biofilm formation in a specific beneficial bacterium. The current proposal seeks to expand these findings to a broader microbiome context, identifying which bacterial and fungal taxa respond to MA enrichment with enhanced biofilm production and carbon sequestration. Future work will isolate and characterize novel microbial candidates with superior biofilm-forming capabilities for potential agricultural application. The research is conducted at the University of Florida with available growth chamber infrastructure and CO2 monitoring capabilities.