Plastic-madera (WPCS) composits are products derived from wood fibers and synthetic polymers such as high density polyethylene-HDPE and polypropylene-PP. WPCs are used in handrails, balconies, windows, enclosures, or in the automotive industry, seeking to replace wood, mainly in places where it is scarce or with low mechanical and durability properties. From an environmental and economic point of view, WPCs production allows us to take advantage of residual lignocellulosic materials of agribusiness and HDPE/PP of recycling systems. However, the mechanical and durability properties of the WPCs, often need to be improved for use in high humidity environments, such as the Ecuadorian coast and the East. An option is to make a pretreatment to lignocellulosic materials through processes such as steam explosion, where hemicellulose is removed, the main cause of the low durability of WPCS. This type of thermochemical pretreatment allows waste use to be complete if processes are integrated into biorefinery concepts, to obtain fuels and bioproducts. The objective of this project is to produce WPCs with improved properties using pretted natural fibers by steam explosion and recycling plastics in biorefinery. WPCS will be obtained from the process with improved properties, ethanol for fuel and fertilizers and fungicides from the liquid fraction of thermal pretreatment. The results will allow progress in the concepts of biorefinerias in Ecuador, showing the possibility of producing bioproducts and biofuels from abundant agroindustrial waste in the country.