- document
-
Köninger, Katharina (author), Grote, Marius (author), Zachos, Ioannis (author), Hollmann, F. (author), Kourist, Robert (author)Oxidoreductases belong to the most-applied industrial enzymes. Nevertheless, they need external electrons whose supply is often costly and challenging. Recycling of the electron donors NADH or NADPH requires the use of additional enzymes and sacrificial substrates. Interestingly, several oxidoreductases accept hydrogen peroxide as electron...journal article 2016
- document
-
Gjonaj, L. (author), Pinkse, M.W.H. (author), Fernandez Fueyo, E. (author), Hollmann, F. (author), Hanefeld, U. (author)Nitrile reductases catalyse a two-step reduction of nitriles to amines. This requires the binding of two NADPH molecules during one catalytic cycle. For the nitrile reductase from E. coli (EcoNR) mass spectrometry studies of the catalytic mechanism were performed. EcoNR is dimeric and has no Rossman fold. It was demonstrated that during...journal article 2016
- document
-
Holtmann, Dirk (author), Hollmann, F. (author)Monooxygenases are promising catalysts because they in principle enable the organic chemist to perform highly selective oxyfunctionalisation reactions that are otherwise difficult to achieve. For this, monooxygenases require reducing equivalents, to allow reductive activation of molecular oxygen at the enzymes' active sites. However, these...journal article 2016
- document
-
Geddes, Alexander (author), Paul, C.E. (author), Hay, Sam (author), Hollmann, F. (author), Scrutton, Nigel S. (author)Understanding the mechanisms of enzymatic hydride transfer with nicotinamide coenzyme biomimetics (NCBs) is critical to enhancing the performance of nicotinamide coenzyme-dependent biocatalysts. Here the temperature dependence of kinetic isotope effects (KIEs) for hydride transfer between "better than nature" NCBs and several ene reductase...journal article 2016
- document
-
Zhou, Pengfei (author), Wang, Xuping (author), Yang, Bo (author), Hollmann, F. (author), Wang, Yonghua (author)Epoxides are important synthetic intermediates for the synthesis of a broad range of industrial products. This study presents a promising solution to the current limitation of enzyme instability. By using simple deep eutectic solvents such as choline chloride/sorbitol, significant stabilization of the biocatalyst has been achieved leading to...journal article 2017
- document
-
Tosstorff, Andreas (author), Kroner, Cora (author), Opperman, Diederik J. (author), Hollmann, F. (author), Holtmann, Dirk (author)Old yellow enzymes are able to catalyze asymmetric C=C reductions. A mediated electroenzymatic process to regenerate the NADPH in combination with an old yellow enzyme was investigated. Due to the fact that the overall process was affected by a broad set of parameters, a design of experiments (DoE) approach was chosen to identify suitable...journal article 2017
- document
-
Zhang, W. (author), Gacs, Jenő (author), Arends, I.W.C.E. (author), Hollmann, F. (author)The aerobic organocatalytic oxidation of alcohols was achieved by using water-soluble sodium anthraquinone sulfonate. Under visible-light activation, this catalyst mediated the aerobic oxidation of alcohols to aldehydes and ketones. The photo-oxyfunctionalization of alkanes was also possible under these conditions.journal article 2017
- document
-
Schmidt, S. (author), Pedroso de Almeida, T. (author), Rother, D (author), Hollmann, F. (author)The one-pot multistep enzymatic oxidation of aliphatic and benzylic alcohols to the corresponding aldehydes combined with their subsequent carboligation to chiral α-hydroxy ketones has been exemplarily evaluated in terms of being a “green” biocatalytic approach. Besides the potential to start from bio-derived alcohols, this concept avoids the...journal article 2017
- document
-
Son, Eun Jin (author), Lee, Sahng Ha (author), Kuk, Su Keun (author), Pesic, M. (author), Choi, Da Som (author), Ko, Jong Wan (author), Kim, Kayoung (author), Hollmann, F. (author), Park, Chan Beum (author)In green plants, solar-powered electrons are transferred through sophistically arranged photosystems and are subsequently channelled into the Calvin cycle to generate chemical energy. Inspired by the natural photosynthetic scheme, a photoelectrochemical cell (PEC) is constructed configured with protonated graphitic carbon nitride (p-g-C<sub>3...journal article 2017
- document
-
Cofactor-Free, Direct Photoactivation of Enoate Reductases for the Asymmetric Reduction of C=C BondsLee, Sahng Ha (author), Choi, Da Som (author), Pesic, M. (author), Lee, Yang Woo (author), Paul, C.E. (author), Hollmann, F. (author), Park, Chan Beum (author)Enoate reductases from the family of old yellow enzymes (OYEs) can catalyze stereoselective trans-hydrogenation of activated C=C bonds. Their application is limited by the necessity for a continuous supply of redox equivalents such as nicotinamide cofactors [NAD(P)H]. Visible light-driven activation of OYEs through NAD(P)H-free, direct...journal article 2017
- document
-
Lan, Dongming (author), Wang, Xuping (author), Zhou, Pengfei (author), Hollmann, F. (author), Wang, Yonghua (author)Deep eutectic solvents act as surfactants in biphasic (hydrophobic/aqueous) reaction mixtures enabling higher interfacial surface areas at lower mechanical stress as compared to simple emulsions. Exploiting this effect the rate of a chemoenzymatic epoxidation reaction was increased more than six-fold.journal article 2017
- document
-
Pesic, M. (author), Fernandez Fueyo, E. (author), Hollmann, F. (author)Old Yellow Enzymes (OYEs) have become practical catalysts for the stereoselective trans-hydrogenation of conjugated C=C-double bonds. Despite their importance, in-depth characterization of their kinetic parameters and factors influencing their activity and stability have largely been neglected in the past years. In this study, we close this...journal article 2017
- document
-
Qi, Jingxian (author), Paul, C.E. (author), Hollmann, F. (author), Tischler, Dirk (author)The oxygen-insensitive azoreductase AzoRo originating from Rhodococcus opacus 1CP was found to be most active at low pH (ca. 4) and high temperature (ca. 50 °C). AzoRo is not an efficient biocatalyst when used at low pH due to stability problems. To overcome this issue, we discovered that AzoRo accepts an alternative electron donor, 1-benzyl...journal article 2017
- document
-
Choi, Da Som (author), Ni, Y. (author), Fernandez Fueyo, E. (author), Lee, Minah (author), Hollmann, F. (author), Park, Chan Beum (author)Peroxygenases are very promising catalysts for oxyfunctionalization reactions. Their practical applicability, however, is hampered by their sensitivity against the oxidant (H<sub>2</sub>O<sub>2</sub>), therefore necessitating in situ generation of H<sub>2</sub>O<sub>2</sub>. Here, we report a photoelectrochemical approach to provide...journal article 2017
- document
-
Wang, Xu Ping (author), Zhou, Peng Fei (author), Li, Zhi Gang (author), Yang, Bo (author), Hollmann, F. (author), Wang, Yong Hua (author)A Ser105Ala mutant of the lipase B from Candida antarctica enables 'perhydrolase-only' reactions. At the example of the chemoenzymatic Baeyer-Villiger oxidation of cyclohexanone, we demonstrate that with this mutant selective oxidation can be achieved in deep eutectic solvent while essentially eliminating the undesired hydrolysis reaction of...journal article 2017
- document
-
Zhou, Pengfei (author), Wang, Xuping (author), Zeng, Chaoxi (author), Wang, Weifei (author), Yang, Bo (author), Hollmann, F. (author), Wang, Yonghua (author)A chemoenzymatic method for the production of epoxidized vegetable oils was developed. The unique combination of the commercial lipase G from Penicillieum camembertii with certain deep eutectic solvents enabled the efficient production of epoxidized vegetable oils.journal article 2017
- document
-
Zhang, W. (author), Bariotaki,, A. (author), Smonou, I. (author), Hollmann, F. (author)Carbon-nanodot-doped g-C3N4 is used as a photocatalyst to promote the aerobic oxidation of alcohols and oxyfunctionalisation of activated hydrocarbons. A critical E-factor analysis of the current reaction system reveals its limitations en route to environmentally acceptable oxidation procedures.journal article 2017
- document
-
Wang, Yonghua (author), Lan, Dongming (author), Durrani, Rabia (author), Hollmann, F. (author)Peroxygenases are promising catalysts for preparative oxyfunctionalization chemistry as they combine the versatility of P450 monooxygenases with simplicity of cofactor-independent enzymes. Though many interesting applications have been reported, today ‘we have only scratched the surface’ and significant efforts are necessary to solve issues...review 2017
- document
-
Younes, S.H.H. (author), Ni, Y. (author), Schmidt, S. (author), Kroutil, Wolfgang (author), Hollmann, F. (author)Alcohol dehydrogenases are well-established catalysts for various reduction reactions. However, the reduction of carboxylic acid derivatives has not yet been reported with these enzymes. In this contribution, we demonstrated that carboxylic acid thioesters could be readily reduced by a range of alcohol dehydrogenases, albeit at significantly...journal article 2017
- document
-
Dong, J. (author), Fernandez Fueyo, E. (author), Li, Jingbo (author), Guo, Zheng (author), Renirie, Rokus (author), Wever, Ron (author), Hollmann, F. (author)The vanadium-dependent chloroperoxidase from Curvularia inaequalis is a stable and efficient biocatalyst for the hydroxyhalogenation of a broad range of alkenes into halohydrins. Up to 1 200 000 TON with 69 s−1 TOF were observed for the biocatalyst. A bienzymatic cascade to yield epoxides as reaction products is presented.journal article 2017