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Rapport2022Öppen tillgång

Climate impact of some alternative uses for the lignin-rich byproduct from yeast oil production

Karlsson Potter, Hanna; Blomqvist, Johanna; Passoth, Volkmar

Sammanfattning

Yeast oil can be produced from lignocellulosic materials such as straw and forest residues by oleaginous yeasts. In the conversion process, cellulose and hemicellulose are consumed to produce the oil, leaving the lignin fraction of the biomass. Some of this fraction is used for internal energy production in the biorefinery, but the remainder is a byproduct from the process. This study explored the climate impact of alternative uses of the lignin-rich byproduct from a lignocellulosic biorefinery producing biodiesel from straw using oleaginous yeast. Three alternative uses were considered: asphalt amendment (replacing bitumen), pyrolysis oil and soil amendment. The climate impact of the biorefinery system included straw harvesting and related soil organic carbon changes, straw transport, and biorefinery processing, including inputs and energy use. The climate impact was analysed using a time-dependent climate model and the commonly used global warming potential metric. The results showed that straw harvesting and use in the biorefinery for production of biofuels and other products, such as asphalt ingredients, was beneficial for the overall climate impact compared with a fossil reference system, even when soil organic carbon losses due to straw harvesting were included. In a climate impact perspective, the most beneficial use of surplus lignin was as asphalt amendment, especially if the asphalt served as a carbon sink.

Nyckelord

biorefinery; climate impact; lignocellulosic biorefinery; biodiesel; soil organic carbon; bitumen

Publicerad i

Mistra Food Futures Report
2022, nummer: 6ISBN: 978-91-8046-755-1, eISBN: 978-91-8046-754-4Utgivare: Swedish University of Agricultural Sciences