Dr. Li Shuai’s research work was published in Science Advances. A collaborative study on an unusual catechyl lignin (C-lignin) present in the seed coats of vanilla (Vanilla planifolia) and various members of the Cactaceae family of the genus Melocactus was recently published in the prestigious journal Science Advances (DOI: 10.1126/sciadv.aau2968). The research work was conducted as a joint effort of several universities and institutes, including University of Wisconsin-Madison, Virginia Tech, University of North Texas, Oak Ridge National Lab, and Kyoto University.

Lignin, a major component of lignocellulosic biomass, is crucial to plant growth and development but is a major impediment to efficient biomass utilization in various processes. Valorizing lignin is increasingly realized as being essential. However, rapid condensation of lignin during acidic extraction leads to the formation of recalcitrant condensed units that, along with similar units and structural heterogeneity in native lignin, drastically limits product yield and selectivity. Catechyl lignin (C-lignin), which is essentially a benzodioxane homopolymer without condensed units, might represent an ideal lignin for valorization, as it circumvents these issues. The study discovered that C-lignin is highly acid-resistant. Hydrogenolysis of C-lignin resulted in the cleavage of all benzodioxane structures to produce catechyl-type monomers in near-quantitative yield with a selectivity of 90% to a single monomer. The monomer could be directly used to replace petroleum-derived phenol. There is therefore considerable potential for economic hydrogenolysis of C-lignin-rich waste biomass resources only now being structurally characterized, such as Jatropha (Jatropha curcas) seed coats and candlenut (Aleurites moluccanus) shells, and via genetic engineering if high levels of C-lignin could be expressed in traditional biomass sources. Such an approach toward significantly valorizing lignins and biomass in biorefining processes would aid process economics.