Project description:Lignin is a universal waste product of the agricultural industry and is currently seen as a potential feedstock for more sustainable manufacturing. While it is the second most abundant biopolymer in the world, most of it is currently burned as it is a very recalcitrant material. Many recent studies, however, have demonstrated the viability of biocatalysis to improve the value of this feedstock and convert it into more useful chemicals, such as polyhydroxybutyrate, and clean fuels like hydrogen and n-butanol. Rhodopseudomonas palustris is a gram-negative bacterium which demonstrates a plethora of desirable metabolic capabilities, including aromatic catabolism useful for lignin degradation. This study uses a multi-omics approach, including the first usage of CRISPRi in R. palustris, to investigate the lignin consumption mechanisms of R. palustris, the essentiality of redox homeostasis to lignin consumption, elucidate a potential lignin catabolic superpathway, and enable more economically viable sustainable lignin valorization processes.
Project description:Very little is known about the mechanism controlling petiole rigidity in sacred lotus (Nelumbo nucifera Gaertn.). To investigate the mechanism controlling the lotus petiole rigidity, morphological and proteomic analyses were performed. Anatomically, there is a great variation between the petioles of floating and vertical leaves. The number of vascular bundles, ligneous cells and thickness of cell wall were higher in the initial vertical leaf petiole (IVP) compared to the initial floating leaf petiole (IFP). A total of 4855 proteins were quantified through comparative proteomic analysis, among which 421 proteins expressed 1.5 folds higher in IFP and 483 proteins expressed 1.5 folds higher in IVP. Protein function categories indicated hundreds of proteins involved in cell wall organization and biosynthesis, and cell wall assembly. Functional enrichment analysis for the differentially abundant proteins indicated the enrichment of 105 proteins in 6 different pathways, while 43 out the total proteins were enriched in lignin biosynthesis pathway. In consistent with genes and proteins expressions in lignin biosynthesis, the contents of lignin monomers precursors were significantly different in IFP and IVP. These findings support the involvement of lignin in lotus petioles rigidity.