The depletion of the fossil fuels claims new energies. The utilization of biofuels and bioenergy has emerged as a viable alternative. Especially, the production of energy and several products is becoming widespread in biorefineries, intended for the efficient conversion of biomass and waste through economically viable processes. More deeply, the green biorefinery refers to the utilization of grassland biomass to produce valuable products like proteins, lactic acid or silage after fractionating the biomass into a press cake and a green juice.
This study is a contribution to the Organofinery project and hypothesises the pretreatment of the press cake can yield several organic products, maximizing the profit and the utilization of grasslands, along with studying the suitability of red clover and the press cake for the production of good quality silage, that can be employed for animal feeding and as a method of preservation of the biogas potential.
Enzymatic hydrolysis of the press cake seems to be a promising alternative for the utilization of this sub-product, as several fiber-bound proteins and sugars are released. The loading of TS and the amount of enzyme included are the most important factors for the optimization of the process.
Ensilaging red clover and the press cake appears to be a viable method for maintaining the feeding value of grasses all year round. However, the ensiled biomass must achieve DM contents over 30% in order to avoid clostridia growth and become suitable for animal feeding. Finally, ensilaging the press cake increased the methane potential in comparison to non-ensiled press cake and therefore it constitutes a suitable method for preserving the methane potential.