TY - JOUR
T1 - Polymerization of coniferyl alcohol by Mn3+-mediated (enzymatic) oxidation
T2 - Effects of H2O2 concentration, aqueous organic solvents, and pH
AU - Taboada-Puig, Roberto
AU - Lú-Chau, Thelmo
AU - Moreira, María
AU - Feijoo, Gumersindo
AU - Lema, Juan
AU - Fagerstedt, Kurt
AU - Ohra-aho, Taina
AU - Liitiä, Tiina
AU - Heikkinen, Harri
AU - Ropponen, Jarmo
AU - Tamminen, Tarja
PY - 2018
Y1 - 2018
N2 - The objective of this study was to evaluate the ability of one versatile peroxidase and the biocatalytically generated complex Mn(III)-malonate to polymerize coniferyl alcohol (CA) to obtain dehydrogenation polymers (DHPs) and to characterize how closely the structures of the formed DHPs resemble native lignin. Hydrogen peroxide was used as oxidant and Mn2+ as mediator. Based on the yields of the polymerized product, it was concluded that the enzymatic reaction should be performed in aqueous solution without organic solvents at 4.5 ≤ pH ≤ 6.0 and with 0.75 ≤ H2O2:CA ratio ≤ 1. The results obtained from the Mn3+-malonate-mediated polymerization showed that the yield was almost 100%. Reaction conditions had, however, effect on the structures of the formed DHPs, as detected by size exclusion chromatography and pyrolysis-GC/MS. It can be concluded that from the structural point of view, the optimal pH for DHP formation using the presently studied system was 3 or 4.5. Low H2O2/CA ratio was beneficial to avoid oxidative side reactions. However, the high frequency of β–β linkages in all cases points to dimer formation between monomeric CA rather than endwise polymerization.
AB - The objective of this study was to evaluate the ability of one versatile peroxidase and the biocatalytically generated complex Mn(III)-malonate to polymerize coniferyl alcohol (CA) to obtain dehydrogenation polymers (DHPs) and to characterize how closely the structures of the formed DHPs resemble native lignin. Hydrogen peroxide was used as oxidant and Mn2+ as mediator. Based on the yields of the polymerized product, it was concluded that the enzymatic reaction should be performed in aqueous solution without organic solvents at 4.5 ≤ pH ≤ 6.0 and with 0.75 ≤ H2O2:CA ratio ≤ 1. The results obtained from the Mn3+-malonate-mediated polymerization showed that the yield was almost 100%. Reaction conditions had, however, effect on the structures of the formed DHPs, as detected by size exclusion chromatography and pyrolysis-GC/MS. It can be concluded that from the structural point of view, the optimal pH for DHP formation using the presently studied system was 3 or 4.5. Low H2O2/CA ratio was beneficial to avoid oxidative side reactions. However, the high frequency of β–β linkages in all cases points to dimer formation between monomeric CA rather than endwise polymerization.
KW - bjerkandera sp
KW - coniferyl alcohol
KW - dehydrogenated polymer
KW - Mn(III)-malonate
KW - polymerization
KW - versatile peroxidase
UR - http://www.scopus.com/inward/record.url?scp=85031091443&partnerID=8YFLogxK
U2 - 10.1002/btpr.2562
DO - 10.1002/btpr.2562
M3 - Article
SN - 8756-7938
VL - 34
SP - 81
EP - 90
JO - Biotechnology Progress
JF - Biotechnology Progress
IS - 1
ER -