Lignin-Degrading Microorganisms in Tropical Forest Soil Under Fluctuating Redox Conditions Characterized

Scientists from different research institutions in the United States (including the Lawrence Berkeley National Lab, Joint Genome Institute (United States Department of Energy, DOE), Joint BioEnergy Institute and the University of California, Berkeley) report the use of "lignin-baited ‘bio-traps', to investigate the microbes and enzymes responsible for lignin decomposition in Puerto Rico tropical forest soils." Exploration of microbial diversity with lignin-degrading capability in these soils may eventually lead to the discovery of new enzymes which can effectively be harnessed for biofuel production applications, particularly for biomass delignification during pretreatment.

One of the interesting features of forest soils in Puerto Rico is the fluctuating anoxic and redox conditions; this might suggest the presence of unique microbial lignin-degraders with lignin-degradation mechanisms that are different from "known fungal decomposers and oxygen-dependent enzyme activities". Results showed that "lignin-amended beads [in the biotraps] have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteriaand Proteobacteria, compared to unamended beads. The scientists inferred that bacteria could play a role in anaerobic lignin decomposition in low and fluctuating redox soils. The full paper is published in the open access journal, PLoS ONE (URL above).