The sixth report of the Intergovernmental Panel on Climate Change emphasizes that the forest-based sector represents an important potential of mitigation actions in the near term, that could enable to limit part of GHG emissions and contribute to reach several Sustainable Development Goals. At the same time, climatic changes have an impact on forests growth, and even though the European countries still show positive net annual forest increments, the tendency is on reduced wood biomass available in a sustainable manner. Optimisation of the use of the woody biomass is thus becoming of the outmost importance. Biorefineries integrated in the pulp industry are among the main actors that participate in this action. The keynote presentation will discuss about two ways to make these biorefineries more sustainable. Cellulose and energy are the two main products of kraft pulp mills. Extractives, through tall oil and turpentine have been valorised for a very long time in softwood mills. Regarding lignin, most of it end up in the recovery boiler, despite the huge amount of research and development studies that have been and are currently going on to find new valorisation pathways. Hemicelluloses, that compose 20 to 30% of the wood mass, are, by comparison much less studied and valorised. A review on processes that could be used to have access to these complex polysaccharides will be given, as well as several examples of valorisation. Cellulose requires to be bleached for several applications. Most mills are still using chlorine dioxide in their bleaching sequences, the use of which might be questionned from an environmental point of view, especially when it is used in a biorefinery. The use of oxygen based oxidants, like oxygen, ozone and hydrogen peroxyde, at different parts of the processes in a biorefinery will be discussed in a second part.