(599f) Investigation and Modeling Natural Biodegradation System in Soil; Application for Designing An Efficient Biological Pretreatment Technology for Biofuel Production

Chandoor, M. - Presenter, Washington State University
Singh, D. - Presenter, Washington State University
Chen, S. - Presenter, Washington State University

During the process of lignocellulosic biomass conversion to Biofuel, the greatest challenge now remains in the efficiency of conversion of the biomass into hydrolysable sugars. As the C-5 andC-6 sugar components are attached and protected by lignin matrix, getting the sugars depend primarily on the level of deconstruction of lignin. The natural biodegradation process of lignocellulosic biomass in the soil provides an excellent platform to investigate how the biomass is converted. The process is essential for maintaining the carbon-cycle in the natural atmosphere, which reflects that the study on the biomass degradation in soil can be a safest model to imprint the lignocellulosic degradation process for obtaining Biofuel.

It is a complex mechanism which involves soil as a support media for the growth and interaction of different sets of microcosm including algae, fungi and bacteria. This work presents the microcosm involved in the biodegradation processes occurring in the soil and detailed structural characterization of biomass reflecting the mechanism of biodegradation process. Understanding of the degradation mechanism in soil will provide important information to improve the current biomass pretreatment technology. In addition to this, the potential lignin degrading microbes/and or microcosm may be useful for the lignocellulosic biodegradation process as well as for the bioremediation of hazardous organic compounds.

In this study, we used wood chips and wheat straw as substrates in the soil. It has characteristics such as carbon content of 2.285 gm/Kg, sulfur content of 0.026 gm /kg and nitrogen content of 0.171 gm/kg. The 3 gms of lignocellulosic samples were incubated with 440 gms of soil at 20 oC for four months and the moisture level was maintained to 15% which issame as in natural condition. The sampling of the biomass was done in every four weeks. The presentation will include three different categories of study. The analysis of structural changes/modification of lignin and the sequential cleavage bond in the structure of lignin observed during the incubation of wood chips and wheat straw in soil for every set of four weeks until about twenty weeks by NMR, FTIR and GC-MS analysis. The second will be the isolation and characterization of the microcosm involved in the lignin degradation process in soil. In this, the strains were isolated from the biomass and characterized on the basis of their ability to decolorize Azo dye. Dye discoloration assay was observed in A647 nm after the strains were grown in LB media with dye concentration of 0.002% incubating at 28 oC for 24 hrs. Interestingly, some of the strains showed high discoloration activity within 16 hrs. The mechanism behind the discoloration and the strains identification is under investigation.

The modeling of the lignin degrading soil system is based on the physical and biochemical conditions in the soil would ultimately provide to design a novel method of pretreatment. As the process is taking place mainly due to the interaction between different sets of microcosm, our presentation would provide a new perspective of pretreatment technology.