On behalf of Foods of Norway, a calculation for yeast has been carried out by NORSUS. The yeast production is based on the process developed in Foods of Norway. Beyond being a delivery to Foods of Norway, this work is also important for further work in the Livestock project where NORSUS is a partner. The project was carried out during 2020 and the study is based on data input from Borregaard and NORCE, who has been a subcontractor for Foods of Norway.
This report documents the life cycle assessment (LCA) of production of yeast based on BALI sugar from spruce. Environmental impact from the production of BALI (Borregaard Advanced Lignin) sugar is calculated from confidential data from Borregaard. The nitrogen source of yeast production can be either inorganic or organic. In this study, data for ammonia, waste and blood have been used. The data basis for the latter two is based on emissions from the chicken slaughter process where economic allocation has been applied. The prices are confidential and not stated in the report. There is a degree of uncertainty to these prices as they may change in a new market.
The results show that BALI sugar accounts for the largest share of the environmental impact for all impact categories, however sugar is also the raw material that makes up the majority in quantity. Ammonia and other raw materials accounts for smaller impacts. The impact from processing of yeast accounts for a small share of climate change, therwise negligible.
If an organic N-source is used, chemicals and minerals are not required. When using offal and blood as Nsources,
the environmental impacts for yeast are lower compared to yeast where the N-source comes from ammonia. The only exception is for land occupation, were the burden is slightly higher for yeast with offal Nsource. How much lower depends on the value of the N-source (economic allocation).
A possible further development of the LCA may be inclusion of the benefit of using the biogenic CO2 emitted from the fermentation process in other industrial purposes (i.e. greenhouse production). Then the environmental impact from the upstream value chain can be allocated between the product(s) and yeast. The environmental impact of yeast will then be reduced accordingly.