Sustainable Electrochemical Depolymerization of Lignin in Reusable Ionic Liquids

Lignin’s aromatic building blocks provide a chemical resource that is, in theory, ideal for substitution of aromatic petrochemicals. Moreover, degradation and valorization of lignin has the potential to generate many high-value chemicals for technical applications. In this study, electrochemical degradation of alkali and Organosolv lignin was performed using the ionic liquids 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and triethylammonium methanesulfonate. The extensive degradation of the investigated lignins with simultaneous almost full recovery of the electrolyte materials provided a sustainable alternative to more common lignin degradation processes. We demonstrate here that both the presence (and the absence) of water during electrolysis and proton transport reactions had significant impact on the degradation efficiency. Hydrogen peroxide radical formation promoted certain electrochemical mechanisms in electrolyte systems “contaminated” with water and increased yields of low molecular weight products significantly. The proposed mechanisms were tentatively confirmed by determining product distributions using a combination of liquid chromatography-mass spectrometry and gas-chromatography-mass spectrometry, allowing measurement of both polar versus non-polar as well as volatile versus non-volatile components in the mixtures

Highly Efficient CYP167A1 (EpoK) dependent Epothilone B Formation and Production of 7-Ketone Epothilone D as a New Epothilone Derivative

Since their discovery in the soil bacterium Sorangium cellulosum, epothilones have emerged as a valuable substance class with promising anti-tumor activity. Because of their benefits in the treatment of cancer and neurodegenerative diseases, epothilones are targets for drug design and pharmaceutical research. The final step of their biosynthesis – a cytochrome P450 mediated epoxidation of epothilone C/D to A/B by CYP167A1 (EpoK) – needs significant improvement, in particular regarding the efficiency of its redox partners. Therefore, we have investigated the ability of various hetero- and homologous redox partners to transfer electrons to EpoK. Hereby, a new hybrid system was established with conversion rates eleven times higher and Vmax of more than seven orders of magnitudes higher as compared with the previously described spinach redox chain. This hybrid system is the most efficient redox chain for EpoK described to date. Furthermore, P450s from So ce56 were identified which are able to convert epothilone D to 14-OH, 21-OH, 26-OH epothilone D and 7-ketone epothilone D. The latter one represents a novel epothilone derivative and is a suitable candidate for pharmacological tests. The results revealed myxobacterial P450s from S. cellulosum So ce56 as promising candidates for protein engineering for biotechnological production of epothilone derivatives