Enhanced lignin biodegradation by consortium of white rot fungi: microbial synergistic effects and product mapping

Abstract

Background As one of the major components of lignocellulosic biomass, lignin has been considered as the most abundant renewable aromatic feedstock in the world. Comparing with thermal or catalytic strategies for lignin degradation, biological conversion is a promising approach featuring with mild conditions and diversity, and has received great attention nowadays. Results In this study, a consortium of white rot fungi composed of Lenzites betulina and Trametes versicolor was employed to enhance the ligninolytic enzyme activity of laccase (Lac) and manganese peroxidase (MnP) under microbial synergism. The maximum enzymatic activity of Lac and MnP was individually 18.06 U mL−1 and 13.58 U mL−1 along with a lignin degradation rate of 50% (wt/wt), which were achieved from batch cultivation of the consortium. The activities of Lac and MnP obtained from the consortium were both improved more than 40%, as compared with monocultures of L. betulina or T. versicolor under the same culture condition. The enhanced biodegradation performance was in accordance with the results observed from scanning electron microscope (SEM) of lignin samples before and after biodegradation, and secondary-ion mass spectrometry (SIMS). Finally, the analysis of heteronuclear single quantum coherence (HSQC) NMR and gas chromatography–mass spectrometry (GC–MS) provided a comprehensive product mapping of the lignin biodegradation, suggesting that the lignin has undergone depolymerization of the macromolecules, side-chain cleavage, and aromatic ring-opening reactions. Conclusions Our results revealed a considerable escalation on the enzymatic activity obtained in a short period from the cultivation of the L. betulina or T. versicolor due to the enhanced microbial synergistic effects, providing a potential bioconversion route for lignin utilization.

Variations in lignin monomer contents and stable hydrogen isotope ratios in methoxy groups during the biodegradation of garden biomass

“…As expected, the biodegradation efficiency in the co-culture (PM + AF experiment) was generally higher than that of the single strains, with a final DWL value as high as 26.7% and a fitted slope of 1.75 ( P < 0.001) for NDL . Usually, a multi-species symbiotic mixture is the best approach to promote diverse enzyme production and synergistic effects 43 . This could be why co-cultivation of different species can trigger more responses to chemical signals than would be possible with a single fungus or bacterium 44 .…”

Endophytes in Lignin Valorization: A Novel Approach

“…For instance, mixed bacterial culture was found to be more efficient in converting Kraft lignin into vanillin ( Baghel and Anandkumar, 2019 ). Similarly, laccase (Lac) and Manganese peroxidase (MnP) activity of Lenzites betulina and Trametes versicolor was enhanced by 40% after taking a consortium as compared to monocultures under the same culture conditions ( Cui et al, 2021 ). In another extensive study, out of several screened consortia from wooden antiques for lignocellulose deconstruction, four different consortia (J-1, J-6, J-8 and J-15) exhibited degradation ability of lignin.…”

Advances in Catalytic Depolymerization of Lignin

“…The ligninolytic enzymatic activity of laccase (LAC) and manganese peroxidase (MnP) was found to be enhanced by the synergistic action of microorganisms in batch culture of a consortium consisting of Lenzites betulina and Trametes versicolor, with maximum enzymatic activities of 18.06 U/mL for LAC and 13.58 U/mL for MnP and the lignin degradation rate of 50 % (wt/wt). [27] By co-culturing T. reesei with the Coprinus comatus, the LAC activity was increased by 2.6-fold compared to the monocultures of C. comatus. [28] In nature, some fungi and bacteria depolymerize lignin by using powerful oxidative enzymes.…”