科研之友
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摘要
Lignin depolymerization mainly involves redox reactions relying on the effective electron transfer. Even though electron mediators were previously used for delignification of paper pulp, no study has established a bioprocess to fragment and solubilize the lignin with an effective laccase-mediator system, in particular, for subsequent microbial bioconversion. Efficient lignin depolymerization was achieved by screening proper electron mediators with laccase to attain a nearly 6-fold increase of kraft lignin solubility compared to the control kraft lignin without laccase treatment. Chemical analysis suggested the release of a low molecular weight fraction of kraft lignin into the solution phase. Moreover, NMR analysis revealed that an efficient enzyme-mediator system can promote the lignin degradation. More importantly, the fundamental mechanisms guided the development of an efficient lignin bioconversion process, where solubilized lignin from laccase-HBT treatment served as a superior substrate for bioconversion by Rhodococcus opacus PD630. The cell growth was increased by 106 fold, and the lipid titer reached 1.02 g/L. Overall, the study has manifested that an efficient enzyme-mediator-microbial system can be exploited to establish a bioprocess to solubilize lignin, cleave lignin linkages, modify the structure, and produce substrates amenable to bioconversion.
- 出版日期2017-3
