Towards a comprehensive understanding of reaction mechanisms of « Lytic polysaccharide monooxygénases » (LPMO) for an optimized hydrolysis of recalcitrant lignocellulose

The production of bioethanol from lignocellulosic substrates depends on efficient enzymatic hydrolysis, which is one of the most expensive steps in the process. The Trichoderma reesei enzymatic cocktail is one of the most efficient, but certain substrates, such as softwood or Miscanthus, remain difficult to degrade with a low sugar yield. IFPEN has been working for many years on improving the cellulase cocktail.
It has been shown that Lytic Polysaccharide Mono Oxygenases (LPMO) are capable of boosting cellulase activity. These copper metalloenzymes which oxidize sugar polymers can constitute a way to improve the cocktail of cellulases on recalcitrant substrates such as sotfwoods but their particularities complicate their industrial implementation. Many parameters can indeed impact their activity and capability to enhance cellulase activity, such as the nature of the co-substrate and electron donor, regioselectivity, pH or the type of substrate.
The thesis aims to identify important features of the primary structure of LPMO which influence their reactivities towards cellulose, the necessary reduction of the copper ion, and their interaction with the substrate. To this end, two wild type enzymes and several variants supposed to impact substrate affinity and reactivity will be generated and biochemically characterized. In addition, the capacity of these LPMOs to act in synergy with T. reesei cellulases on a real substrate will be evaluated. 
As the present PhD thesis is part of a collaborative project, the enzymes will moreover be characterized by partner laboratories with expertise in biophysical methods, such as NMR, electrochemistry and EPR (electron paramagnetic resonance) as well as in theoretical modelling.  This multidisciplinary approach, combining fundamental and applied aspects, will thus allow gathering complementary data to acquire essential knowledge on LPMO which is key for improvement of LPMO for industrial processes.
 

IFP Energies nouvelles is a French public-sector research, innovation and training center. Its mission is to develop efficient, economical, clean and sustainable technologies in the fields of energy, transport and the environment. For more information, see our WEB site. IFPEN offers a stimulating research environment, with access to first in class laboratory infrastructures and computing facilities. IFPEN offers competitive salary and benefits packages. All PhD students have access to dedicated seminars and training sessions.

Master’s degree in biology or biochemistry. The candidate should have very good theoretical and practical knowledge of biochemical methods and enzymology. Basic knowledge of structural biology and biophysical methods are desirable.

Fluency in English, basic knowledge of French

Soft skills : Team work, communication skills, curiosity