BioChem - DOS

The liquid fraction from hydrothermal pretreatment of wheat straw provides lytic polysaccharide monooxygenases with both electrons and H2O2 co-substrate

Biotechnology for biofuels

Kont, Riin; Pihlajaniemi, Ville; Borisova, Anna S.; Aro, Nina; Marjamaa, Kaisa; Loogen, Judith; Bü chs, Jochen; Eijsink, Vincent G. H.; Kruus, Kristiina; Vä ljamä e, Priit

<P><B>Abstract</B>Background<P>Enzyme-aided valorization of lignocellulose represents a green and sustainable alternative to the traditional chemical industry. The recently discovered lytic polysaccharide monooxygenases (LPMOs) are important components of the state-of-the art enzyme cocktails for cellulose conversion. Yet, these monocopper enzymes are poorly characterized in terms of their kinetics, as exemplified by the growing evidence for that H2O2may be a more efficient co-substrate for LPMOs than O2. LPMOs need external electron donors and one key question of relevance for bioprocess development is whether the required reducing power may be provided by the lignocellulosic substrate.</P>Results<P>Here, we show that the liquid fraction (LF) resulting from hydrothermal pretreatment of wheat straw supports LPMO activity on both chitin and cellulose. The initial, transient activity burst of the LPMO reaction was caused by the H2O2present in the LF before addition of LPMO, while the steady-state rate of LPMO reaction was limited by the LPMO-independent production of H2O2in the LF. H2O2is an intermediate of LF oxidation as evidenced by a slow H2O2accumulation in LF, despite high H2O2production rates. This H2O2scavenging ability of LF is important since high concentrations of H2O2may lead to irreversible inactivation of LPMOs.</P>Conclusions<P>Our results support the growing understanding that fine-tuned control over the rates of H2O2production and consumption in different, enzymatic and non-enzymatic reactions is essential for harnessing the full catalytic potential of LPMOs in lignocellulose valorization.</P></P>

2019

Springer (Biomed Central Ltd.)

cc-by

1754-6834

12

pp.235

10.1186/s13068-019-1578-5

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART109991367

https://biotechnologyforbiofuels.biomedcentral.com/track/pdf/10.1186/s13068-019-1578-5