Naturally p-Hydroxybenzoylated Lignins in Palms

Fachuang Lu; Steven D. Karlen; Matt Regner; Hoon Kim; Sally A. Ralph; Run-Cang Sun; Ken-ichi Kuroda; Mary Ann Augustin; Raymond Mawson; Henry Sabarez; Tanoj Singh; Gerardo Jimenez-Monteon; Sarani Zakaria; Stefan Hill; Philip J. Harris; Wout Boerjan; Curtis G. Wilkerson; Shawn D. Mansfield; John Ralph

doi:10.1007/s12155-015-9583-4

Naturally p-Hydroxybenzoylated Lignins in Palms

Formally Refereed

Authors:

Fachuang Lu, Steven D. Karlen, Matt Regner, Hoon Kim, Sally A. Ralph, Run-Cang Sun, Ken-ichi Kuroda, Mary Ann Augustin, Raymond Mawson, Henry Sabarez, Tanoj Singh, Gerardo Jimenez-Monteon, Sarani Zakaria, Stefan Hill, Philip J. Harris, Wout Boerjan, Curtis G. Wilkerson, Shawn D. Mansfield, John Ralph

Year:

2015

Type:

Scientific Journal

Station:

Forest Products Laboratory

DOI:

https://doi.org/10.1007/s12155-015-9583-4

Source:

BioEnergy Research

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Abstract

The industrial production of palm oil concurrently generates a substantial amount of empty fruit bunch (EFB) fibers that could be used as a feedstock in a lignocellulose based biorefinery. Lignin byproducts generated by this process may offer opportunities for the isolation of value-added products, such as p-hydroxybenzoate (pBz), to help offset operating costs. Analysis of the EFB lignin by nuclear magnetic resonance (NMR) spectroscopy clearly revealed the presence of bound acetate and pBz, with saponification revealing that 1.1 wt% of the EFB was pBz; with a lignin content of 22.7 %, 4.8 % of the lignin is pBz that can be obtained as a pure component for use as a chemical feedstock. Analysis of EFB lignin by NMR and derivatization followed by reductive cleavage (DFRC) showed that pBz selectively acylates the γ-hydroxyl group of S units. This selectivity suggests that pBz, analogously with acetate in kenaf, p-coumarate in grasses, and ferulate in a transgenic poplar augmented with a feruloyl-CoAmonolignol transferase (FMT), is incorporated into the growing lignin chain via its γ-p-hydroxybenzoylated monolignol conjugate. Involvement of such conjugates in palm lignification is proven by the observation of novel phydroxybenzoylated non-resinol β–β-coupled units in the lignins. Together, the data implicate the existence of phydroxybenzoyl- CoA:monolignol transferases that are involved in lignification in the various willows (Salix spp.), poplars and aspen (Populus spp., family Salicaceae), and palms (family Arecaceae) that have p-hydroxybenzoylated lignins. Even without enhancing the levels by breeding or genetic engineering, current palm oil EFB ‘wastes’ should be able to generate a sizeable stream of p-hydroxybenzoic acid that offers opportunities for the development of value-added products derived from the oil palm industry.

Keywords

Lignin acylation, Transferase, NMR, DFRC method, Poplar, p-Hydroxybenzoic acid, Monolignol

Citation

Lu, Fachuang; Karlen, Steven D.; Regner, Matt; Kim, Hoon; Ralph, Sally A.; Sun, Run-Cang; Kuroda, Ken-ichi; Augustin, Mary Ann; Mawson, Raymond; Sabarez, Henry; Singh, Tanoj; Jimenez-Monteon, Gerardo; Zakaria, Sarani; Hill, Stefan; Harris, Philip J.; Boerjan, Wout; Wilkerson, Curtis G.; Mansfield, Shawn D.; Ralph, John. 2015. Naturally p-Hydroxybenzoylated Lignins in Palms. BioEnergy Research. 8(3): 934-952.