The biorefinery process for second generation hemicellulose sugars at Sappi involves recovering them from the prehydolysate liquor, and then separating them from the associated lignin and organic acids. There are various levels of processing and purification depending on end uses. The products we are targeting include sugar alcohols such as xylitol (a low energy sugar substitute), lactic acid (used in the production of polylactic acid (PLA), a renewable plastic), glycols (the main applications being for the production of PET for plastic bottles and unsaturated polyester resins and other products.
We are looking into ways to use the sugars (as well as lignin and organic acids) extracted from the wood during the pulping process, including entering into partnerships, to modify these extracts into higher value products for use in a wide variety of applications.
Second generation sugars are attractive because they do not compete with first generation sugars which are sourced from agricultural crops. This is extremely important because of a rapidly growing global population and worldwide pressure on agricultural resources. There is a strong, growing market demand for renewable biochemicals from non-food sources as companies intensify their search for ‘green’ products that offer enhanced sustainability and also offer product value chains with a lower carbon footprint, all of these aimed at a better quality of life for all.
In terms of sustainability, Sappi’s pulp mills have an advantage because the sugars are a co-product from an existing process and removing lignin and sugars can offer benefits in terms of pulp production efficiencies.
Sappi has commissioned the construction of a second-generation sugar extraction demonstration plant at Ngodwana Mill in Mpumalanga Province, South Africa. The demonstration plant will extract hemicellulose sugars and lignin from Sappi’s existing dissolving pulp line. The sugars platform will include beneficiation to higher value organic acids, glycols and sugar alcohols which find application in many everyday products.
New developments in wood processing supports the move to a biobased economy that utilises materials that are renewable and biodegradable and that do not compete with food sources.
Sappi’s patented process, developed with Edinburgh Napier University, reduces the energy required to process woodfibres into nanocellulose thus enhancing our product’s sustainability.
Lignosulphonate is a highly soluble lignin derivative and a product of the sulphite pulping process.
Sappi is focusing on green energy generation in line with our strategic focus to derive value from energy opportunities and in light of sustainability and efficiency drivers.